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Policy encouraging earlier hip fracture surgery can decrease the long-term mortality of elderly patients
Accepted Manuscript Title: Policy encouraging earlier hip fracture surgery can decrease the long-term mortality of elderly patients Author: Kobi Peleg Michael Rozenfeld Irina Radomislensky Ilya Novikov Laurence S. Freedman Avi Israeli PII: DOI: Reference:
S0020-1383(14)00133-8 http://dx.doi.org/doi:10.1016/j.injury.2014.03.009 JINJ 5677
To appear in:
Injury, Int. J. Care Injured
Received date: Revised date: Accepted date:
9-12-2013 6-2-2014 14-3-2014
Please cite this article as: Peleg K, Rozenfeld M, Radomislensky I, Novikov I, Freedman LS, Israeli A, Policy encouraging earlier hip fracture surgery can decrease the long-term mortality of elderly patients, Injury (2014), http://dx.doi.org/10.1016/j.injury.2014.03.009 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Policy encouraging earlier hip fracture surgery can decrease the long-term mortality of elderly patients Kobi Peleg PhD MPH1,2, Michael Rozenfeld MA1,2, Irina Radomislensky1 BSc, Ilya Novikov PhD3, Laurence S. Freedman PhD3,Avi Israeli MD MPH4
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1) National Center for Trauma & Emergency Medicine Research, Gertner Institute for Epidemiology and Health Policy Research, Tel-Hashomer, Israel 2) School of Public Health, Tel-Aviv University, Israel.
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3) Biostatistics Unit, Gertner Institute for Epidemiology and Health Policy Research, Tel-
Hashomer, Israel
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4) Hebrew University, Hadassah School of Public Health, Jerusalem, Israel.
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Correspondence and reprints: Kobi Peleg.
E-mail: [email protected]; Phone: 972-3-5354252; Fax: 972-3-5353393. Address: National Center for Trauma and Emergency Medicine Research, Gertner
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Institute, Tel-Hashomer, Israel, 52621.
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Keywords: hip fracture; earlier surgery; DRG; long-term mortality.
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Policy encouraging earlier hip fracture surgery can decrease the long-term mortality of elderly patients Abstract Background: In April 2004 the Israeli Ministry of Health decided to condition DRG
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payment for hip surgery by time between hospitalization and operation, giving a fine
for every day’s delay beyond 48 hours. An evaluation study performed two years after the reform has shown the positive influence of the reform on patient's survival in the
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hospital. This study evaluates the impact of the reform on the longer-term mortality of
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patients.
Methods: A retrospective study based on data from 9 hospitals of the national trauma registry available for the years 2001-2007, with surveillance on two-year survival
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through data of Ministry of the Interior. The study population includes patients aged 65 and above with an isolated hip fracture following trauma. Mortality curves and Cox Regression were utilized to compare the influence of different parameters on
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long-term mortality.
Results: Earlier surgery had a significant positive impact on survival through the
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whole length of the study period. In the period after the introduction of the new reimbursement system for hip fracture surgeries, a significant decrease in the longer-
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term mortality was observed up to 6 months of follow-up, even when adjusted by
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patients' age, gender and the receiving hospital. After 6 months there was no further decrease in relative risk, though the survival advantage remained with patients hospitalized after the reform.
Conclusions: The reform appears successful in decreasing the longer-term patient mortality after hip fracture through influencing surgical practice.
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Introduction Hip fractures are frequent in the elderly population and are associated with much suffering, decrease in quality of life and increased mortality, while the cost to the healthcare system is high1,2. According to many studies, patients who sustained a hip
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fracture are at much higher risk of dying as compared to other representatives of their age group1-3.
The recommended method of treating a hip fracture is either replacement or fixation
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surgery. Most sources agree that surgery should be performed in the first 24 hours and not later than 48 hours after hospitalization4-7. Many studies have shown that delay of
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surgery can lead to increased morbidity, mortality and length of stay in the hospital4-7. The growing awareness of the effects of delayed surgery of hip fractures on medical
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outcomes brought a change in the system of reimbursement of Israeli hospitals for these surgeries. In April 2004 the Director of the Israel Ministry of Health (IMH) issued a directive to impose a differential pricing on hip fixations, conditioned by time
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of surgery. The directive defined full DRG payment for hip fixations of all patients with diagnosis of isolated hip fracture only if the surgery was performed in the first 48
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hours of hospitalization. In cases of later surgery not justified by medical
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considerations such as clear contraindications, each day of delay would further subtract from the payment. This new policy was introduced for all Israeli hospitals
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performing hip fracture surgeries, while demanding a consistent registration of surgery times.
In 2007 the Israeli National Center for Trauma and Emergency Medicine Research performed a study, sponsored by the National Institute for Health Services Research, whose purpose was to measure the impact of this policy change on volume of delayed surgeries and in-hospital mortality8. The study found an increase of 35% in volume of operations in the first 48 hours of hospitalization and a decrease of one day in median waiting time for hip fixations in the period after the change in the reimbursement system compared to the period before it. In the later period, in-hospital mortality decreased by more than 30%8.
The drop in in-hospital mortality shown by that study demonstrated the short-term advantages that occurred after introduction of the new method of reimbursing hospitals for hip fracture surgeries, but many other studies stress the importance of considering the effects of earlier surgery for hip fracture on longer-term mortality6,9-11.
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Recent studies have shown that in different spans of follow-up after hip fracture surgery, there are variations in the importance of different factors influencing mortality3,12. These factors such as patients' age, gender and the hospital environment should be considered when trying to establish a relationship between time of surgery
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and longer-term mortality. In this study we investigate the longer-term effects of the change in reimbursement
system on mortality following hip fracture, and to what extent the possible changes in
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mortality after the reform could be ascribed to decreased time of surgery.
•
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2. Objectives
To examine whether introduction of differential pricing of hip fracture surgery
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conditioned by time of surgery lowered the long-term mortality of patients aged 65+. •
To find out whether shorter waiting times for hip fracture surgery of patients
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aged 65+ are associated with lower long-term mortality. Materials and Methods
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This is a retrospective study of patients included in the Israeli National Trauma
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Registry (ITR) during the period 2001-2007 (with year 2004 omitted as the year of the policy change). Patients aged 65 and above with an isolated diagnosis of hip fracture
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(ICD-9-CM 820)13 who were hospitalized at all 6 level I trauma centers in Israel and
at 3 regional trauma centers were included in the study. These 9 hospitals were chosen because they were included in the Registry during all 7 years of the study. The data on patients in the registry were linked to mortality data from the population database of the Ministry of the Interior in order to obtain two-year follow-up on their survival. Altogether 10,900 patients met the inclusion criteria. The main outcome measure was longer-term mortality, with emphasis on 6-month, one-year and two-year mortality. Comparisons of interest were: between patients operated in less than 48 hours since arrival, those operated after 48 hours and unoperated patients; and between the period before the change of reimbursement policy (2001-2003) and the period after (2005-2007). In addition to survival analysis of patients over the full two-year follow-up period, we also performed survival analysis of patients over the 6 months to 1 year period and from the one-year to two-
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year period. This was done in order to analyze whether the factors influencing mortality change over time. Chi-square tests were used to compare categorical variables between the period before and after the reimbursement policy change. Survival curves were estimated by the
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Kaplan-Meier method and converted to mortality curves by subtracting survival percentages from 100%; Cox regression was used to estimate Hazard Ratios (HR) comparing the periods before and after reimbursement policy and adjusted for
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patient's age, gender and the receiving hospital. The time of surgery was then inserted into the model in order to estimate to what extent the difference between the two
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policy periods was explained by the decreased waiting time for hip-fracture surgery.
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A value of p<0.05 was considered to be statistically significant.
Results
To compare the long-term mortality before and after the change of reimbursement
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policy, we began our analysis with a comparison of the patients in the two periods (Table 1).
Females represented the majority (71%) in both periods. The age distribution was
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slightly more heterogeneous in the first period, but in both periods almost half of the
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patients belonged to the 75-84 age-group, with mean age of 81 (2001-2004: Me=81.11/Std=7.39; 2005-2007: Me=81.27/Std=7.29). More patients required ICU in
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the second period and 55% of patients in the second period entered a rehabilitation unit, compared to only 45% in the first period. The change in reimbursement policy led to more patients being operated (88% v 86%) and substantially more patients operated in the first 48 hours since hospitalization (53% v 39%). However, even after the reform, about 12% of the patients received conservative treatment. The patients in the second period had greatly reduced LOS and lower in-hospital mortality (2.4% v 3.5%).
The difference in mortality between the two periods reduced after one-month followup, but increased again after three months, the absolute difference in percentage remaining at a stable level of ~2% over 6 to 24 months (which is more than 100 actual patient lives saved just in the hospitals participating in the study). The difference after 6-months follow-up was the most statistically significant of these comparisons. Figure 1 shows the sharp decline in previously stable levels of 6-month mortality one year after the reform stabilizing again at a lower level. 5
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The association of early surgery with patient's survival over two-years of follow-up in both study periods is summarized by mortality curves (Figure 2). Expectedly, patients who did not undergo hip fracture surgery had consistently higher mortality than operated patients. The figure also shows a clear separation between the mortality
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curves according to waiting time to surgery, with patients operated in the first 48 hours since hospitalization having the lower mortality. The influence of these factors was identical in both study periods. The significance of differences between the
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curves was additionally proven by Cox Regression, predicting mortality by time to surgery, adjusted for receiving hospital and patients' age and gender in a 2-year
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follow-up.
We have also found that both among patients operated in less than 48 hours and
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among those operated later there was no difference in mortality between the two study periods (Figure 3).
In order to evaluate the impact of the change in reimbursement policy on patients'
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longer-term mortality, we calculated the Hazard Ratios (HR) over a 6-months followup interval in the post-reform period in reference to the pre-reform period, while adjusting for patient's age, gender, and by the receiving hospital (inserted sequentially
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into the regression model). The results are presented in Table 2, where each
factor.
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consecutive model signifies expansion of the independent variables list by one more
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We have found that 6-month mortality significantly decreased in the period after the change in reimbursement policy. The magnitude of this difference was largest when all adjusting factors were present in the equation, with an estimate that patients hospitalized in the second period were 13% less likely to die after hip fracture than in the first period.
As expected, mortality increased with age and was significantly associated with the receiving hospital; males had significantly higher mortality than females. When the surgery variable was inserted into the model, the effect of period on mortality became insignificant, suggesting that the difference between the before and after reimbursement policy change periods was, in fact, explained by the change in surgery practice (decrease in waiting time and increase in percentage of patients operated upon). When the model was applied to 1-year and 2-year mortality, it showed mixed results. When the period 0-1 year or 2-year was analyzed, the results were similar to the 6
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previously described 0-6 months analysis. Nevertheless, the influence of policy period on mortality decreased in the longer spans of follow-up (HR 0.91 (CI: 0.840.98) over 0-1 year; HR 0.94 (CI: 0.88-1.01) over 0-2 years). The length of follow-up had a similar effect on the influence of gender on mortality (HR 1.75 (CI: 1.61-1.91)
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over 0-1 year; HR 1.69 (CI: 1.58-1.82) over 0-2 years). However, when the model was applied over the 6-month to 1-year period and over the 1 year to 2 years period, there were no differences found in the hazard ratios of
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patients in the two policy periods (HR 1.03 (CI: 0.87-1.21) over 6 months to 1 year;
have no association with mortality over these periods.
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HR 1.04 (CI: 0.91-1.17) at 1 year to 2 years). The receiving hospital was also found to
In order to account for possible gender-related bias in the impact of the
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reimbursement reform we analyzed the interaction between gender and waiting time to hip fracture surgery in both periods in addition to access to rehabilitation care (Table 3).
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The results show that women received significant preference for earlier surgery (as well as for the surgery itself) in both periods. They were also better influenced by the reform as their percentage of early surgeries increased by 14.8% as opposed to a
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13.0% increase among males. In the second period, women also had greater access to
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rehabilitation care (56.8% vs. 53.1%). Males were found to be somewhat younger than females in the second period, but the percentage of patients older than 85 was
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similar in both genders.
Discussion
The goal of our study was to assess the impact of the new reimbursement system, that was aimed at stimulating reduced waiting time for hip fracture surgery, on long-term mortality of patents older than 65. For that goal we sought to compare the clinical outcomes of patients hospitalized due to isolated hip fracture before the new system was implemented to the patients hospitalized in the later period in a two-year followup. Our results have clearly shown that following the reform of reimbursement for hip fracture surgeries in Israel not only did the percentage of earlier surgeries increase, the LOS decrease and in-patient mortality decrease as shown by the previous study8, but also longer-term mortality of patients decreased. The period after the reimbursement reform may have seen some clinical improvements, such as enhanced medication 7
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regiments, advances in surgical implants and, as we have shown in this study – greater access to postoperative rehabilitation. However, the fact that when patient survival was analyzed separately among "operated <48 hours" and "operated 48< hours" populations, no differences were found between the two periods, can suggest that the
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reimbursement reform and the subsequent decrease in waiting times for hip fracture surgery could provide an explanation for the general decrease in long-term mortality in the second period.
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Many previous studies have shown the benefits of earlier hip fracture surgery for
elderly patients' survival and functional recovery4-7. However, there is still no clear
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consensus on the subject, as other studies demonstrated that waiting time for surgery loses its importance when adjusted for other factors, such as patent's age and gender,
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the nature and the severity of previous comorbidities and the variability in levels of receiving hospitals14-17. From our results it can be clearly determined that hip fracture surgery in the first 48 hours since hospitalization was associated with a decrease in
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longer-term mortality of elderly patients even when adjusted for demographic and organizational factors. Though our database did not provide us with information on patients’ comorbidities, the apparent influence of earlier surgery on survival was very
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strong even after adjustment for the available factors.
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We also found that the association of the period before and after the new reimbursement system with patients' survival varied between different periods of
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follow-up. After 3-months follow-up, the reform regained its positive impact on patients' survival, but after adjusting by patient's age, gender and the receiving hospital, the impact after 6 months of follow-up was no longer seen. The most likely explanation for this finding is that as time passes since surgery, the advantages of early surgery dwindles and other external factors that could influence mortality, such as co-morbidity, come into play1,9,10. Previous research has already pointed to the fact that when considering the long-term mortality of hip fracture patients, different factors become dominant at different periods of follow-up3,12.
Special attention was drawn in the literature to the impact of age on mortality risk at different follow-up periods among women, who usually comprise the majority of hip fracture patients3. It was found that the risk for long-term mortality after hip fracture is the greatest among females aged 65-69 years, while in the first year of follow-up the risk is similar for the whole age span of women older than 653. Our study has found that age had a monotonic influence on mortality among both genders regardless 8
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of the length of follow-up period. On the other hand, the influence of gender on mortality decreased through the length of follow-up following the first 6 months after hospitalization, during which males had a hazard ratio of 1.84 as compared to females. The almost two-fold disadvantage of males in survival after hip-fracture is
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well documented in the literature and is usually explained by their inferior previous health condition and higher risk of infection11,18,19. The higher volume of co-
morbidities among male hip fracture patients can also explain the preference that
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females in our study received for earlier hip fracture surgery, as patients who would have greater benefit from the surgery could have been prioritized by the treating
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hospital11,15,17,19. Female patients in our study were also found to have greater access to rehabilitation care in the period after the change in the reimbursement policy. This
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could also be the result of conscious hospital policy change after the reform of the reimbursement system and one of the factors contributing to the observed decrease in mortality12.
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Future research should target the specific policy of the treating hospitals regarding the influence of demographic factors on their priorities for treating hip fracture patients and the possibilities of influencing this prioritization by policy.
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The understanding of driving forces behind hospital policies is especially important
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when trying to influence them by reform20-22. There is always a concern that conditioning the financial reimbursement of hospitals for earlier hip fracture surgeries
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would induce the surgeons to operate patients with contraindication for such surgery. If this was to happen, the reform could lead to an increase rather than decrease in mortality. In population aged 65 years and older it would be common to encounter comorbidities and use of medications that would provide a contraindication for surgery
9,15-17,23
. The fact that even after the conditioning of DRG payments by time of surgery
only about 53% of patients in our study were operated early and about 12% received conservative treatment, may indicate that hospitals still give more weight to clinical considerations even when provided with economic stimuli.
Limitations This study had several limitations that should be taken into consideration when interpreting the results. Our main limitation was the lack of data on co-morbidities in the Israeli Trauma Registry. If that information was available for the study, the found
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differences in mortality could have much more definitively be attributed to the change in reimbursement policy and consequent decrease in waiting times for surgery. An additional limitation is the fact that during the years of the study not all Israeli trauma centers were included in the registry, thus limiting the scope of our
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conclusions to hospitals actually analyzed in the study.
Conclusions
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Our study indicates that a reform of reimbursement for hip fracture surgery
significantly increased the proportion of patients receiving hip-fracture surgery within
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48 hours of admission and thereby decreased the longer-term mortality of elderly patients up to 6 months after surgery. The reform did not influence the mortality rate
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beyond 6 months following surgery, though the advantage in the total percentage of survivors was preserved up to 2 years after surgery. The evidence suggests also that as a result of the reform, hospitals may change their policies of prioritizing patients for
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treatment, while trying to find a balance between the preference for earlier surgeries
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and the clinical contra-indications for such surgeries.
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References 1. Brauer CA, Coca-Perraillon M, Cutler DM. Incidence and mortality of hip fractures in the United States. JAMA. 2009;302(14): 1573-1579. 2. Tsuboi M, Hasegawa Y, Suzuki S, Wingstrand H, Thorngren K. Mortality and
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mobility after hip fracture in Japan: a ten-year follow-up. J Bone Joint Surg Br. 2007; 89(4) 461-6.
3. LeBlanc ES, Hillier TA, Pedula KL, Rizzo JH, Cawthon PM, Fink HA, et al. Hip
Women. Arch Intern Med. 2011;171(20):1831-1837.
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Fracture and Increased Short-term but Not Long-term Mortality in Healthy Older
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4. Smith EB, Parvizi J, Purtill JJ. Delayed surgery for patients with femur and hip fractures-risk of deep venous thrombosis. J Trauma. 2011 Jun;70(6):E113-6.
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5. Simunovic N, Devereaux PJ, Sprague S, Guyatt GH, Schemitsch E, Debeer J, et al. Effect of early surgery after hip fracture on mortality and complications: systematic review and meta-analysis. CMAJ. 2010 Oct 19;182(15):1609-16.
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6. Shiga T, Wajima Z, Ohe Y. Is operative delay associated with increased mortality of hip fracture patients? Systematic review, meta-analysis, and meta-regression.
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Can J Anaesth. 2008 Mar;55(3):146-54.
7. Carretta E, Bochicchio V, Rucci P, Fabbri G, Laus M, Fantini MP. Hip fracture:
Mar;35(3):419-24.
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effectiveness of early surgery to prevent 30-day mortality. Int Orthop. 2011
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8. Peleg K, Savitsky B, Berlovitz Y, ITG, Israeli A. Different reimbursement influences surviving of hip fracture in elderly patients. Injury. 2011
Feb;42(2):128-32.
9. Söderqvist A, Ekström W, Ponzer S, Pettersson H, Cederholm T, Dalén N, et al. Prediction of mortality in elderly patients with hip fractures: a two-year prospective study of 1,944 patients. Gerontology. 2009;55(5):496-504.
10. Kim SM, Moon YW, Lim SJ, Yoon BK, Min YK, Lee DY, et al. Prediction of survival, second fracture, and functional recovery following the first hip fracture surgery in elderly patients. Bone. 2012 Mar 6. [Epub ahead of print] 11. Wehren LE, Hawkes WG, Orwig DL, Hebel JR, Zimmerman SI, Magaziner J. Gender differences in mortality after hip fracture: the role of infection. J Bone Miner Res. 2003 Dec;18(12):2231-7.
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12. Castronuovo E, Pezzotti P, Franzo A, Di Lallo D, Guasticchi G. Early and late mortality in elderly patients after hip fracture: a cohort study using administrative health databases in the Lazio region, Italy. BMC Geriatr. 2011 Aug 5;11:37. 13. Supplementary classification of external causes of injury and poisoning (E880-
Reno, Nevada: Channel publishing; 1994: 1061-1124.
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E999). In: Puckett CD, ed. The educational annotation of ICD-9-CM. 4th ed.
14. Franzo A, Francescutti C, Simon G. Risk factors correlated with post-operative
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mortality for hip fracture surgery in the elderly: a population-based approach. Eur J Epidemiol. 2005;20(12):985-91.
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15. Librero J, Peiró S, Leutscher E, Merlo J, Bernal-Delgado E, Ridao M, et al. Timing of surgery for hip fracture and in-hospital mortality: a retrospective
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population-based cohort study in the Spanish National Health System. BMC Health Serv Res. 2012 Jan 18;12:15.
16. Di Monaco M. Factors affecting functional recovery after hip fracture in the
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elderly. Crit Rev Phys Rehabil Med. 2005;16(3).
17. Vidan MT, Sanchez E, Gracia Y, Maranon E, Vaquero J, Serra JA. Causes and Effects of Surgical Delay in Patients with Hip Fracture: A Cohort Study. Ann
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Intern Med. 2011;155:226-233.
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18. Sterling RS. Gender and Race/Ethnicity Differences in Hip Fracture Incidence, Morbidity, Mortality, and Function. Clin Orthop Relat Res. 2011; 469:1913–1918.
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19. Roche JJW, Wenn RT, Sahota O, Moran, CG. Effect of comorbidities and postoperative complications on mortality after hip fracture in elderly people: prospective observational cohort study. BMJ. 2005; 331(7529): 1374.
20. Forgione DA, Vermeer TE, Surysekar K, Wrieden JA, Plante CA. The impact of DRG-based payment systems on quality of health care in OECD countries. J Health Care Finance. 2004 Fall;31(1):41-54.
21. Pinnarelli L, Nuti S, Sorge C, Davoli M, Fusco D, Agabiti N, et al. What drives hospital performance? The impact of comparative outcome evaluation of patients admitted for hip fracture in two Italian regions. BMJ Qual Saf. 2012 Feb;21(2):127-34. 22. Taheri PA, Butz DA, Greenfield LJ. Academic health systems management: the rationale behind capitated contracts. Ann Surg. 2000 Jun;231(6):849-59.
23. Lalmohamed A, Vestergaard P, Klop C, Grove EL, de Boer A, Leufkens HG, et al. Timing of acute myocardial infarction in patients undergoing total hip or knee 12
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replacement: a nationwide cohort study. Arch Intern Med. 2012
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Sep;172(16):1229-35.
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Figure legends Figure 1: The trend of 6-months mortality through the study period. Figure 2: Mortality Curve: Two-year mortality by waiting time for hip fracture surgery in both study periods (Curves estimated by the Kaplan-Meier method; presented differences are significant (p value<0.01).
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Figure 3: Mortality Curve: Two-year mortality by study period among patients
operated in the first 48 hours and those operated later (Curves estimated by the Kaplan-
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Meier method).
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Figure 1: The trend of 6-months mortality through the study period.
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Figure 2: Mortality Curve: Two-year mortality by waiting time for hip fracture surgery in both study periods.* 2005-2007 (N=5,362)
A
0 1
2 3 4
5 6
7
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Length of follow-up (months)
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2001-2003 (N=5,538)
B
1
2
3 4
5 6
7
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Length of follow-up (months)
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0
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Time to Surgery
Curves estimated by the Kaplan-Meier method; presented differences are significant (p value<0.01).
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*
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Time to Surgery
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Figure 3: Mortality Curve: Two-year mortality by study period among patients operated in the first 48 hours and those operated later.* Time to surgery 48< hours
0 1
2
3 4
5 6
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A
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Length of follow-up (months)
Time to surgery <48 hours
2
3 4
5 6
7
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Length of follow-up (months)
Curves estimated by the Kaplan-Meier method; no significant difference was found.
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*
1
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0
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B
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Table1: Comparison of patients in two study periods (% (n)).
2005-2007
(N=5,538)
(N=5,362)
Male
28.93 (1602)
28.95 (1589)
Female
71.07 (3936)
71.05 (3773)
65-74
19.75 (1094)
18.35 (984)
75-84
45.92 (2543)
49.01 (2628)
85+
34.33 (1901)
32.64 (1750)
Rehabilitation** Yes
45.02 (2493)
55.71 (2987)
Gender
Age**
LOS**
0-3
5.27 (391)
4-6
17.95 (991)
7-13
53.60 (2959)
49.36 (2641)
14+
23.18 (1280)
12.88 (689)
<48 hours
38.59 (2133)
52.80 (2826)
47.24 (2611)
35.24 (1886)
14.17 (783)
11.96 (640)
>48 hours
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No surgery
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(21 values are missing)
6.58 (352)
31.18 (1668)
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(29 values are missing)
Time to surgery**
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Parameter
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2001-2003
3.54 (196)
2.35 (126)
5.40 (299)
5.02 (269)
11.11 (615)
9.88 (530)
15.78 (874)
13.84 (742)
12-month mortality*
20.98 (1162)
19.12 (1025)
24-month mortality*
29.79 (1650)
27.68 (1484)
1-month mortality 3-month mortality*
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6-month mortality**
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In-hospital mortality**
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Period
* Significant difference between periods (p value<0.05). ** Significant difference between periods (p value<0.01).
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Table 2: Cox Regression models: 6-month mortality in two policy periods adjusted by receiving hospital, patient's age and gender, and by time of surgery. Model 2
HR, 95% CI Model 3
Model 4
Model 5
0.91, 0.82–0.99 1
0.89, 0.81–0.98 1
0.88, 0.80–0.97 1
0.87, 0.79–0.96 1
0.94, 0.85–1.04 1
0.0001
0.0001
0.0001
Age (adjustment only)* p-value -
-
0.0001
0.0001
0.0001
Gender Male
-
-
-
Female
-
-
-
1.84, 1.66–2.03 1
1.78, 1.61–1.96 1
Time to surgery No surgery
-
-
-
-
>48 hours
-
-
-
-
<48 hours
-
-
-
-
3.88, 3.41–4.41 1.51, 1.34–1.70 1
Period 2005-2007 2001-2003
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+
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(Reference group)
(Reference group)
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Hospital (adjustment only)+ p-value -
0.0001
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(Reference group)
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Model 1
Variable
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All 9 hospitals that contributed data to the study. * Age was inserted as a continuous variable; the mortality grew with age monotonically.
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Table 3: Gender comparison: age structure, access to Rehabilitation Care and waiting time for hip fracture surgery in both policy periods (% (n)).
48 hours<
46.8 (746)
47.5 (1865)
36.1 (573)
34.9 (1313)
No surgery
16.5* (264)
13.2* (519)
14.1* (223)
11.1* (416)
Rehabilitation Yes
44.0 (705)
45.4 (2148)
53.1* (844)
56.8* (2143)
No
56.0 (897)
54.6 (1788)
46.9* (745)
43.2* (1629)
65-74
21.5 (345)
19.0 (749)
21.3* (338)
17.1* (646)
75-84
45.2 (724)
46.2 (1819)
46.1* (732)
50.3* (1896)
85+
33.3 (533)
34.8 (1368)
32.7 (519)
32.6 (1230)
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Age
2005-2007 Male Female 49.8* (791) 54.1* (2035)
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<48 hours
2001-2003 Male Female 36.8* (589) 39.3* (1544)
Parameter Time to surgery
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* Significant difference between genders.
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Acknowledgements This study was funded by a grant from Israel's National Institute for Health Policy and Health Services Research (NIHP). The funding source played no role in the
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investigation itself.
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Conflict of interest statement None of the authors has any Conflicts of Interest to declare.
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S0020-1383(14)00133-8 http://dx.doi.org/doi:10.1016/j.injury.2014.03.009 JINJ 5677
To appear in:
Injury, Int. J. Care Injured
Received date: Revised date: Accepted date:
9-12-2013 6-2-2014 14-3-2014
Please cite this article as: Peleg K, Rozenfeld M, Radomislensky I, Novikov I, Freedman LS, Israeli A, Policy encouraging earlier hip fracture surgery can decrease the long-term mortality of elderly patients, Injury (2014), http://dx.doi.org/10.1016/j.injury.2014.03.009 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Policy encouraging earlier hip fracture surgery can decrease the long-term mortality of elderly patients Kobi Peleg PhD MPH1,2, Michael Rozenfeld MA1,2, Irina Radomislensky1 BSc, Ilya Novikov PhD3, Laurence S. Freedman PhD3,Avi Israeli MD MPH4
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1) National Center for Trauma & Emergency Medicine Research, Gertner Institute for Epidemiology and Health Policy Research, Tel-Hashomer, Israel 2) School of Public Health, Tel-Aviv University, Israel.
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3) Biostatistics Unit, Gertner Institute for Epidemiology and Health Policy Research, Tel-
Hashomer, Israel
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4) Hebrew University, Hadassah School of Public Health, Jerusalem, Israel.
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Correspondence and reprints: Kobi Peleg.
E-mail: [email protected]; Phone: 972-3-5354252; Fax: 972-3-5353393. Address: National Center for Trauma and Emergency Medicine Research, Gertner
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Institute, Tel-Hashomer, Israel, 52621.
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Keywords: hip fracture; earlier surgery; DRG; long-term mortality.
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Policy encouraging earlier hip fracture surgery can decrease the long-term mortality of elderly patients Abstract Background: In April 2004 the Israeli Ministry of Health decided to condition DRG
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payment for hip surgery by time between hospitalization and operation, giving a fine
for every day’s delay beyond 48 hours. An evaluation study performed two years after the reform has shown the positive influence of the reform on patient's survival in the
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hospital. This study evaluates the impact of the reform on the longer-term mortality of
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patients.
Methods: A retrospective study based on data from 9 hospitals of the national trauma registry available for the years 2001-2007, with surveillance on two-year survival
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through data of Ministry of the Interior. The study population includes patients aged 65 and above with an isolated hip fracture following trauma. Mortality curves and Cox Regression were utilized to compare the influence of different parameters on
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long-term mortality.
Results: Earlier surgery had a significant positive impact on survival through the
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whole length of the study period. In the period after the introduction of the new reimbursement system for hip fracture surgeries, a significant decrease in the longer-
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term mortality was observed up to 6 months of follow-up, even when adjusted by
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patients' age, gender and the receiving hospital. After 6 months there was no further decrease in relative risk, though the survival advantage remained with patients hospitalized after the reform.
Conclusions: The reform appears successful in decreasing the longer-term patient mortality after hip fracture through influencing surgical practice.
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Introduction Hip fractures are frequent in the elderly population and are associated with much suffering, decrease in quality of life and increased mortality, while the cost to the healthcare system is high1,2. According to many studies, patients who sustained a hip
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fracture are at much higher risk of dying as compared to other representatives of their age group1-3.
The recommended method of treating a hip fracture is either replacement or fixation
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surgery. Most sources agree that surgery should be performed in the first 24 hours and not later than 48 hours after hospitalization4-7. Many studies have shown that delay of
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surgery can lead to increased morbidity, mortality and length of stay in the hospital4-7. The growing awareness of the effects of delayed surgery of hip fractures on medical
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outcomes brought a change in the system of reimbursement of Israeli hospitals for these surgeries. In April 2004 the Director of the Israel Ministry of Health (IMH) issued a directive to impose a differential pricing on hip fixations, conditioned by time
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of surgery. The directive defined full DRG payment for hip fixations of all patients with diagnosis of isolated hip fracture only if the surgery was performed in the first 48
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hours of hospitalization. In cases of later surgery not justified by medical
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considerations such as clear contraindications, each day of delay would further subtract from the payment. This new policy was introduced for all Israeli hospitals
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performing hip fracture surgeries, while demanding a consistent registration of surgery times.
In 2007 the Israeli National Center for Trauma and Emergency Medicine Research performed a study, sponsored by the National Institute for Health Services Research, whose purpose was to measure the impact of this policy change on volume of delayed surgeries and in-hospital mortality8. The study found an increase of 35% in volume of operations in the first 48 hours of hospitalization and a decrease of one day in median waiting time for hip fixations in the period after the change in the reimbursement system compared to the period before it. In the later period, in-hospital mortality decreased by more than 30%8.
The drop in in-hospital mortality shown by that study demonstrated the short-term advantages that occurred after introduction of the new method of reimbursing hospitals for hip fracture surgeries, but many other studies stress the importance of considering the effects of earlier surgery for hip fracture on longer-term mortality6,9-11.
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Recent studies have shown that in different spans of follow-up after hip fracture surgery, there are variations in the importance of different factors influencing mortality3,12. These factors such as patients' age, gender and the hospital environment should be considered when trying to establish a relationship between time of surgery
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and longer-term mortality. In this study we investigate the longer-term effects of the change in reimbursement
system on mortality following hip fracture, and to what extent the possible changes in
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mortality after the reform could be ascribed to decreased time of surgery.
•
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2. Objectives
To examine whether introduction of differential pricing of hip fracture surgery
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conditioned by time of surgery lowered the long-term mortality of patients aged 65+. •
To find out whether shorter waiting times for hip fracture surgery of patients
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aged 65+ are associated with lower long-term mortality. Materials and Methods
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This is a retrospective study of patients included in the Israeli National Trauma
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Registry (ITR) during the period 2001-2007 (with year 2004 omitted as the year of the policy change). Patients aged 65 and above with an isolated diagnosis of hip fracture
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(ICD-9-CM 820)13 who were hospitalized at all 6 level I trauma centers in Israel and
at 3 regional trauma centers were included in the study. These 9 hospitals were chosen because they were included in the Registry during all 7 years of the study. The data on patients in the registry were linked to mortality data from the population database of the Ministry of the Interior in order to obtain two-year follow-up on their survival. Altogether 10,900 patients met the inclusion criteria. The main outcome measure was longer-term mortality, with emphasis on 6-month, one-year and two-year mortality. Comparisons of interest were: between patients operated in less than 48 hours since arrival, those operated after 48 hours and unoperated patients; and between the period before the change of reimbursement policy (2001-2003) and the period after (2005-2007). In addition to survival analysis of patients over the full two-year follow-up period, we also performed survival analysis of patients over the 6 months to 1 year period and from the one-year to two-
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year period. This was done in order to analyze whether the factors influencing mortality change over time. Chi-square tests were used to compare categorical variables between the period before and after the reimbursement policy change. Survival curves were estimated by the
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Kaplan-Meier method and converted to mortality curves by subtracting survival percentages from 100%; Cox regression was used to estimate Hazard Ratios (HR) comparing the periods before and after reimbursement policy and adjusted for
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patient's age, gender and the receiving hospital. The time of surgery was then inserted into the model in order to estimate to what extent the difference between the two
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policy periods was explained by the decreased waiting time for hip-fracture surgery.
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A value of p<0.05 was considered to be statistically significant.
Results
To compare the long-term mortality before and after the change of reimbursement
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policy, we began our analysis with a comparison of the patients in the two periods (Table 1).
Females represented the majority (71%) in both periods. The age distribution was
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slightly more heterogeneous in the first period, but in both periods almost half of the
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patients belonged to the 75-84 age-group, with mean age of 81 (2001-2004: Me=81.11/Std=7.39; 2005-2007: Me=81.27/Std=7.29). More patients required ICU in
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the second period and 55% of patients in the second period entered a rehabilitation unit, compared to only 45% in the first period. The change in reimbursement policy led to more patients being operated (88% v 86%) and substantially more patients operated in the first 48 hours since hospitalization (53% v 39%). However, even after the reform, about 12% of the patients received conservative treatment. The patients in the second period had greatly reduced LOS and lower in-hospital mortality (2.4% v 3.5%).
The difference in mortality between the two periods reduced after one-month followup, but increased again after three months, the absolute difference in percentage remaining at a stable level of ~2% over 6 to 24 months (which is more than 100 actual patient lives saved just in the hospitals participating in the study). The difference after 6-months follow-up was the most statistically significant of these comparisons. Figure 1 shows the sharp decline in previously stable levels of 6-month mortality one year after the reform stabilizing again at a lower level. 5
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The association of early surgery with patient's survival over two-years of follow-up in both study periods is summarized by mortality curves (Figure 2). Expectedly, patients who did not undergo hip fracture surgery had consistently higher mortality than operated patients. The figure also shows a clear separation between the mortality
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curves according to waiting time to surgery, with patients operated in the first 48 hours since hospitalization having the lower mortality. The influence of these factors was identical in both study periods. The significance of differences between the
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curves was additionally proven by Cox Regression, predicting mortality by time to surgery, adjusted for receiving hospital and patients' age and gender in a 2-year
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follow-up.
We have also found that both among patients operated in less than 48 hours and
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among those operated later there was no difference in mortality between the two study periods (Figure 3).
In order to evaluate the impact of the change in reimbursement policy on patients'
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longer-term mortality, we calculated the Hazard Ratios (HR) over a 6-months followup interval in the post-reform period in reference to the pre-reform period, while adjusting for patient's age, gender, and by the receiving hospital (inserted sequentially
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into the regression model). The results are presented in Table 2, where each
factor.
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consecutive model signifies expansion of the independent variables list by one more
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We have found that 6-month mortality significantly decreased in the period after the change in reimbursement policy. The magnitude of this difference was largest when all adjusting factors were present in the equation, with an estimate that patients hospitalized in the second period were 13% less likely to die after hip fracture than in the first period.
As expected, mortality increased with age and was significantly associated with the receiving hospital; males had significantly higher mortality than females. When the surgery variable was inserted into the model, the effect of period on mortality became insignificant, suggesting that the difference between the before and after reimbursement policy change periods was, in fact, explained by the change in surgery practice (decrease in waiting time and increase in percentage of patients operated upon). When the model was applied to 1-year and 2-year mortality, it showed mixed results. When the period 0-1 year or 2-year was analyzed, the results were similar to the 6
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previously described 0-6 months analysis. Nevertheless, the influence of policy period on mortality decreased in the longer spans of follow-up (HR 0.91 (CI: 0.840.98) over 0-1 year; HR 0.94 (CI: 0.88-1.01) over 0-2 years). The length of follow-up had a similar effect on the influence of gender on mortality (HR 1.75 (CI: 1.61-1.91)
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over 0-1 year; HR 1.69 (CI: 1.58-1.82) over 0-2 years). However, when the model was applied over the 6-month to 1-year period and over the 1 year to 2 years period, there were no differences found in the hazard ratios of
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patients in the two policy periods (HR 1.03 (CI: 0.87-1.21) over 6 months to 1 year;
have no association with mortality over these periods.
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HR 1.04 (CI: 0.91-1.17) at 1 year to 2 years). The receiving hospital was also found to
In order to account for possible gender-related bias in the impact of the
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reimbursement reform we analyzed the interaction between gender and waiting time to hip fracture surgery in both periods in addition to access to rehabilitation care (Table 3).
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The results show that women received significant preference for earlier surgery (as well as for the surgery itself) in both periods. They were also better influenced by the reform as their percentage of early surgeries increased by 14.8% as opposed to a
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13.0% increase among males. In the second period, women also had greater access to
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rehabilitation care (56.8% vs. 53.1%). Males were found to be somewhat younger than females in the second period, but the percentage of patients older than 85 was
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similar in both genders.
Discussion
The goal of our study was to assess the impact of the new reimbursement system, that was aimed at stimulating reduced waiting time for hip fracture surgery, on long-term mortality of patents older than 65. For that goal we sought to compare the clinical outcomes of patients hospitalized due to isolated hip fracture before the new system was implemented to the patients hospitalized in the later period in a two-year followup. Our results have clearly shown that following the reform of reimbursement for hip fracture surgeries in Israel not only did the percentage of earlier surgeries increase, the LOS decrease and in-patient mortality decrease as shown by the previous study8, but also longer-term mortality of patients decreased. The period after the reimbursement reform may have seen some clinical improvements, such as enhanced medication 7
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regiments, advances in surgical implants and, as we have shown in this study – greater access to postoperative rehabilitation. However, the fact that when patient survival was analyzed separately among "operated <48 hours" and "operated 48< hours" populations, no differences were found between the two periods, can suggest that the
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reimbursement reform and the subsequent decrease in waiting times for hip fracture surgery could provide an explanation for the general decrease in long-term mortality in the second period.
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Many previous studies have shown the benefits of earlier hip fracture surgery for
elderly patients' survival and functional recovery4-7. However, there is still no clear
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consensus on the subject, as other studies demonstrated that waiting time for surgery loses its importance when adjusted for other factors, such as patent's age and gender,
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the nature and the severity of previous comorbidities and the variability in levels of receiving hospitals14-17. From our results it can be clearly determined that hip fracture surgery in the first 48 hours since hospitalization was associated with a decrease in
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longer-term mortality of elderly patients even when adjusted for demographic and organizational factors. Though our database did not provide us with information on patients’ comorbidities, the apparent influence of earlier surgery on survival was very
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strong even after adjustment for the available factors.
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We also found that the association of the period before and after the new reimbursement system with patients' survival varied between different periods of
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follow-up. After 3-months follow-up, the reform regained its positive impact on patients' survival, but after adjusting by patient's age, gender and the receiving hospital, the impact after 6 months of follow-up was no longer seen. The most likely explanation for this finding is that as time passes since surgery, the advantages of early surgery dwindles and other external factors that could influence mortality, such as co-morbidity, come into play1,9,10. Previous research has already pointed to the fact that when considering the long-term mortality of hip fracture patients, different factors become dominant at different periods of follow-up3,12.
Special attention was drawn in the literature to the impact of age on mortality risk at different follow-up periods among women, who usually comprise the majority of hip fracture patients3. It was found that the risk for long-term mortality after hip fracture is the greatest among females aged 65-69 years, while in the first year of follow-up the risk is similar for the whole age span of women older than 653. Our study has found that age had a monotonic influence on mortality among both genders regardless 8
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of the length of follow-up period. On the other hand, the influence of gender on mortality decreased through the length of follow-up following the first 6 months after hospitalization, during which males had a hazard ratio of 1.84 as compared to females. The almost two-fold disadvantage of males in survival after hip-fracture is
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well documented in the literature and is usually explained by their inferior previous health condition and higher risk of infection11,18,19. The higher volume of co-
morbidities among male hip fracture patients can also explain the preference that
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females in our study received for earlier hip fracture surgery, as patients who would have greater benefit from the surgery could have been prioritized by the treating
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hospital11,15,17,19. Female patients in our study were also found to have greater access to rehabilitation care in the period after the change in the reimbursement policy. This
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could also be the result of conscious hospital policy change after the reform of the reimbursement system and one of the factors contributing to the observed decrease in mortality12.
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Future research should target the specific policy of the treating hospitals regarding the influence of demographic factors on their priorities for treating hip fracture patients and the possibilities of influencing this prioritization by policy.
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The understanding of driving forces behind hospital policies is especially important
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when trying to influence them by reform20-22. There is always a concern that conditioning the financial reimbursement of hospitals for earlier hip fracture surgeries
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would induce the surgeons to operate patients with contraindication for such surgery. If this was to happen, the reform could lead to an increase rather than decrease in mortality. In population aged 65 years and older it would be common to encounter comorbidities and use of medications that would provide a contraindication for surgery
9,15-17,23
. The fact that even after the conditioning of DRG payments by time of surgery
only about 53% of patients in our study were operated early and about 12% received conservative treatment, may indicate that hospitals still give more weight to clinical considerations even when provided with economic stimuli.
Limitations This study had several limitations that should be taken into consideration when interpreting the results. Our main limitation was the lack of data on co-morbidities in the Israeli Trauma Registry. If that information was available for the study, the found
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differences in mortality could have much more definitively be attributed to the change in reimbursement policy and consequent decrease in waiting times for surgery. An additional limitation is the fact that during the years of the study not all Israeli trauma centers were included in the registry, thus limiting the scope of our
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conclusions to hospitals actually analyzed in the study.
Conclusions
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Our study indicates that a reform of reimbursement for hip fracture surgery
significantly increased the proportion of patients receiving hip-fracture surgery within
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48 hours of admission and thereby decreased the longer-term mortality of elderly patients up to 6 months after surgery. The reform did not influence the mortality rate
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beyond 6 months following surgery, though the advantage in the total percentage of survivors was preserved up to 2 years after surgery. The evidence suggests also that as a result of the reform, hospitals may change their policies of prioritizing patients for
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treatment, while trying to find a balance between the preference for earlier surgeries
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and the clinical contra-indications for such surgeries.
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References 1. Brauer CA, Coca-Perraillon M, Cutler DM. Incidence and mortality of hip fractures in the United States. JAMA. 2009;302(14): 1573-1579. 2. Tsuboi M, Hasegawa Y, Suzuki S, Wingstrand H, Thorngren K. Mortality and
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mobility after hip fracture in Japan: a ten-year follow-up. J Bone Joint Surg Br. 2007; 89(4) 461-6.
3. LeBlanc ES, Hillier TA, Pedula KL, Rizzo JH, Cawthon PM, Fink HA, et al. Hip
Women. Arch Intern Med. 2011;171(20):1831-1837.
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Fracture and Increased Short-term but Not Long-term Mortality in Healthy Older
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4. Smith EB, Parvizi J, Purtill JJ. Delayed surgery for patients with femur and hip fractures-risk of deep venous thrombosis. J Trauma. 2011 Jun;70(6):E113-6.
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5. Simunovic N, Devereaux PJ, Sprague S, Guyatt GH, Schemitsch E, Debeer J, et al. Effect of early surgery after hip fracture on mortality and complications: systematic review and meta-analysis. CMAJ. 2010 Oct 19;182(15):1609-16.
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6. Shiga T, Wajima Z, Ohe Y. Is operative delay associated with increased mortality of hip fracture patients? Systematic review, meta-analysis, and meta-regression.
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Can J Anaesth. 2008 Mar;55(3):146-54.
7. Carretta E, Bochicchio V, Rucci P, Fabbri G, Laus M, Fantini MP. Hip fracture:
Mar;35(3):419-24.
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effectiveness of early surgery to prevent 30-day mortality. Int Orthop. 2011
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8. Peleg K, Savitsky B, Berlovitz Y, ITG, Israeli A. Different reimbursement influences surviving of hip fracture in elderly patients. Injury. 2011
Feb;42(2):128-32.
9. Söderqvist A, Ekström W, Ponzer S, Pettersson H, Cederholm T, Dalén N, et al. Prediction of mortality in elderly patients with hip fractures: a two-year prospective study of 1,944 patients. Gerontology. 2009;55(5):496-504.
10. Kim SM, Moon YW, Lim SJ, Yoon BK, Min YK, Lee DY, et al. Prediction of survival, second fracture, and functional recovery following the first hip fracture surgery in elderly patients. Bone. 2012 Mar 6. [Epub ahead of print] 11. Wehren LE, Hawkes WG, Orwig DL, Hebel JR, Zimmerman SI, Magaziner J. Gender differences in mortality after hip fracture: the role of infection. J Bone Miner Res. 2003 Dec;18(12):2231-7.
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12. Castronuovo E, Pezzotti P, Franzo A, Di Lallo D, Guasticchi G. Early and late mortality in elderly patients after hip fracture: a cohort study using administrative health databases in the Lazio region, Italy. BMC Geriatr. 2011 Aug 5;11:37. 13. Supplementary classification of external causes of injury and poisoning (E880-
Reno, Nevada: Channel publishing; 1994: 1061-1124.
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E999). In: Puckett CD, ed. The educational annotation of ICD-9-CM. 4th ed.
14. Franzo A, Francescutti C, Simon G. Risk factors correlated with post-operative
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mortality for hip fracture surgery in the elderly: a population-based approach. Eur J Epidemiol. 2005;20(12):985-91.
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15. Librero J, Peiró S, Leutscher E, Merlo J, Bernal-Delgado E, Ridao M, et al. Timing of surgery for hip fracture and in-hospital mortality: a retrospective
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population-based cohort study in the Spanish National Health System. BMC Health Serv Res. 2012 Jan 18;12:15.
16. Di Monaco M. Factors affecting functional recovery after hip fracture in the
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elderly. Crit Rev Phys Rehabil Med. 2005;16(3).
17. Vidan MT, Sanchez E, Gracia Y, Maranon E, Vaquero J, Serra JA. Causes and Effects of Surgical Delay in Patients with Hip Fracture: A Cohort Study. Ann
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Intern Med. 2011;155:226-233.
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18. Sterling RS. Gender and Race/Ethnicity Differences in Hip Fracture Incidence, Morbidity, Mortality, and Function. Clin Orthop Relat Res. 2011; 469:1913–1918.
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19. Roche JJW, Wenn RT, Sahota O, Moran, CG. Effect of comorbidities and postoperative complications on mortality after hip fracture in elderly people: prospective observational cohort study. BMJ. 2005; 331(7529): 1374.
20. Forgione DA, Vermeer TE, Surysekar K, Wrieden JA, Plante CA. The impact of DRG-based payment systems on quality of health care in OECD countries. J Health Care Finance. 2004 Fall;31(1):41-54.
21. Pinnarelli L, Nuti S, Sorge C, Davoli M, Fusco D, Agabiti N, et al. What drives hospital performance? The impact of comparative outcome evaluation of patients admitted for hip fracture in two Italian regions. BMJ Qual Saf. 2012 Feb;21(2):127-34. 22. Taheri PA, Butz DA, Greenfield LJ. Academic health systems management: the rationale behind capitated contracts. Ann Surg. 2000 Jun;231(6):849-59.
23. Lalmohamed A, Vestergaard P, Klop C, Grove EL, de Boer A, Leufkens HG, et al. Timing of acute myocardial infarction in patients undergoing total hip or knee 12
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replacement: a nationwide cohort study. Arch Intern Med. 2012
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Sep;172(16):1229-35.
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Figure legends Figure 1: The trend of 6-months mortality through the study period. Figure 2: Mortality Curve: Two-year mortality by waiting time for hip fracture surgery in both study periods (Curves estimated by the Kaplan-Meier method; presented differences are significant (p value<0.01).
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Figure 3: Mortality Curve: Two-year mortality by study period among patients
operated in the first 48 hours and those operated later (Curves estimated by the Kaplan-
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Meier method).
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Figure 1: The trend of 6-months mortality through the study period.
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Figure 2: Mortality Curve: Two-year mortality by waiting time for hip fracture surgery in both study periods.* 2005-2007 (N=5,362)
A
0 1
2 3 4
5 6
7
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Length of follow-up (months)
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2001-2003 (N=5,538)
B
1
2
3 4
5 6
7
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Length of follow-up (months)
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0
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Time to Surgery
Curves estimated by the Kaplan-Meier method; presented differences are significant (p value<0.01).
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*
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Time to Surgery
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Figure 3: Mortality Curve: Two-year mortality by study period among patients operated in the first 48 hours and those operated later.* Time to surgery 48< hours
0 1
2
3 4
5 6
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A
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Length of follow-up (months)
Time to surgery <48 hours
2
3 4
5 6
7
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Length of follow-up (months)
Curves estimated by the Kaplan-Meier method; no significant difference was found.
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*
1
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0
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B
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Table1: Comparison of patients in two study periods (% (n)).
2005-2007
(N=5,538)
(N=5,362)
Male
28.93 (1602)
28.95 (1589)
Female
71.07 (3936)
71.05 (3773)
65-74
19.75 (1094)
18.35 (984)
75-84
45.92 (2543)
49.01 (2628)
85+
34.33 (1901)
32.64 (1750)
Rehabilitation** Yes
45.02 (2493)
55.71 (2987)
Gender
Age**
LOS**
0-3
5.27 (391)
4-6
17.95 (991)
7-13
53.60 (2959)
49.36 (2641)
14+
23.18 (1280)
12.88 (689)
<48 hours
38.59 (2133)
52.80 (2826)
47.24 (2611)
35.24 (1886)
14.17 (783)
11.96 (640)
>48 hours
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No surgery
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(21 values are missing)
6.58 (352)
31.18 (1668)
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(29 values are missing)
Time to surgery**
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Parameter
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2001-2003
3.54 (196)
2.35 (126)
5.40 (299)
5.02 (269)
11.11 (615)
9.88 (530)
15.78 (874)
13.84 (742)
12-month mortality*
20.98 (1162)
19.12 (1025)
24-month mortality*
29.79 (1650)
27.68 (1484)
1-month mortality 3-month mortality*
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6-month mortality**
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In-hospital mortality**
ip t
Period
* Significant difference between periods (p value<0.05). ** Significant difference between periods (p value<0.01).
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Table 2: Cox Regression models: 6-month mortality in two policy periods adjusted by receiving hospital, patient's age and gender, and by time of surgery. Model 2
HR, 95% CI Model 3
Model 4
Model 5
0.91, 0.82–0.99 1
0.89, 0.81–0.98 1
0.88, 0.80–0.97 1
0.87, 0.79–0.96 1
0.94, 0.85–1.04 1
0.0001
0.0001
0.0001
Age (adjustment only)* p-value -
-
0.0001
0.0001
0.0001
Gender Male
-
-
-
Female
-
-
-
1.84, 1.66–2.03 1
1.78, 1.61–1.96 1
Time to surgery No surgery
-
-
-
-
>48 hours
-
-
-
-
<48 hours
-
-
-
-
3.88, 3.41–4.41 1.51, 1.34–1.70 1
Period 2005-2007 2001-2003
d
+
M
(Reference group)
(Reference group)
us
an
Hospital (adjustment only)+ p-value -
0.0001
cr
(Reference group)
ip t
Model 1
Variable
Ac ce p
te
All 9 hospitals that contributed data to the study. * Age was inserted as a continuous variable; the mortality grew with age monotonically.
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Table 3: Gender comparison: age structure, access to Rehabilitation Care and waiting time for hip fracture surgery in both policy periods (% (n)).
48 hours<
46.8 (746)
47.5 (1865)
36.1 (573)
34.9 (1313)
No surgery
16.5* (264)
13.2* (519)
14.1* (223)
11.1* (416)
Rehabilitation Yes
44.0 (705)
45.4 (2148)
53.1* (844)
56.8* (2143)
No
56.0 (897)
54.6 (1788)
46.9* (745)
43.2* (1629)
65-74
21.5 (345)
19.0 (749)
21.3* (338)
17.1* (646)
75-84
45.2 (724)
46.2 (1819)
46.1* (732)
50.3* (1896)
85+
33.3 (533)
34.8 (1368)
32.7 (519)
32.6 (1230)
cr
us
Age
2005-2007 Male Female 49.8* (791) 54.1* (2035)
ip t
<48 hours
2001-2003 Male Female 36.8* (589) 39.3* (1544)
Parameter Time to surgery
Ac ce p
te
d
M
an
* Significant difference between genders.
20
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Acknowledgements This study was funded by a grant from Israel's National Institute for Health Policy and Health Services Research (NIHP). The funding source played no role in the
Ac ce p
te
d
M
an
us
cr
ip t
investigation itself.
21
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Ac ce p
te
d
M
an
us
cr
ip t
Conflict of interest statement None of the authors has any Conflicts of Interest to declare.
22
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