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Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (≥65 years old): A study of 453 consecutive elderly spine surgery patients
Journal of Clinical Neuroscience xxx (2017) xxx–xxx
Contents lists available at ScienceDirect
Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn
Case study
Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (65 years old): A study of 453 consecutive elderly spine surgery patients Aladine A. Elsamadicy, Timothy Y. Wang, Adam G. Back, Emily Lydon, Gireesh B. Reddy, Isaac O. Karikari, Oren N. Gottfried ⇑ Department of Neurosurgery, Duke University Medical Center, Durham, NC, United States
a r t i c l e
i n f o
Article history: Received 30 November 2016 Accepted 12 February 2017 Available online xxxx Keywords: Delirium 30-Day readmission Spine surgery
a b s t r a c t In the last decade, costs of U.S. healthcare expenditures have been soaring, with billions of dollars spent on hospital readmissions. Identifying causes and risk factors can reduce soaring readmission rates and help lower healthcare costs. The aim of this is to determine if post-operative delirium in the elderly is an independent risk factor for 30-day hospital readmission after spine surgery. The medical records of 453 consecutive elderly (65 years old) patients undergoing spine surgery at Duke University Medical Center from 2008 to 2010 were reviewed. We identified 17 (3.75%) patients who experienced postoperative delirium according to DSM-V criteria. Patient demographics, comorbidities, and postoperative complication rates were collected for each patient. Elderly patients experiencing postoperative delirium had an increased length of hospital stay (10.47 days vs. 5.70 days, p = 0.009). Complication rates were similar between the cohorts with the post-operative delirium patients having increased UTI and superficial surgical site infections. In total, 12.14% of patients were re-admitted within 30-days of discharge, with post-operative delirium patients experiencing approximately a 4-fold increase in 30-day readmission rates (Delirium: 41.18% vs. No Delirium: 11.01%, p = 0.002). In a multivariate logistic regression analysis, post-operative delirium is an independent predictor of 30-day readmission after spine surgery in the elderly (p = 0.03). Elderly patients experiencing post-operative delirium after spine surgery is an independent risk factor for unplanned readmission within 30-days of discharge. Preventable measures and early awareness of post-operative delirium in the elderly may help reduce readmission rates. Ó 2017 Elsevier Ltd. All rights reserved.
1. Introduction In the last decade, costs of U.S. healthcare expenditures have dramatically increased, with billions of dollars spent on hospital readmissions. Centers for Medicare & Medicaid Services (CMS) estimates that in 2004, over $17 billion was spent on potentially preventable, unplanned readmissions [1]. In 2013, approximately 18% of Medicare patients were readmitted to the hospital within 30 days, amounting to almost $26 billion billed towards Medicare [2,3]. Under the Patient Protection and Affordable Care Act, the Hospital Readmissions Reduction Program (HRRP) allows for CMS to penalize hospitals on Medicare reimbursements for 30-day readmission rates [3]. As a result, hospital administration now ⇑ Corresponding author at: Department of Neurosurgery, Duke University Medical Center, Duke South Zone Blue, Durham, NC 27705, United States. E-mail address: [email protected] (O.N. Gottfried).
tracks 30-day readmission rates as a metric of clinical performance and quality of care. Identifying causes and risk factors of 30-day readmission in the elderly population is necessary to reduce soaring readmission rates and healthcare costs. Post-operative delirium is a risk factor that has been associated with increased in-hospital mortality, complications, and length of hospital stay after surgery [4–6]. Hospitalized elderly patients have an increased susceptibility to neurocognitive disorders, such as delirium and dementia, which are frequently overlooked and commonly misdiagnosed [7,8]. Recently, there has been an increase in elderly patients undergoing elective spine surgery, as well as increased rates of postoperative delirium following spine surgery [9]. In a retrospective study of 578,457 patients who underwent lumbar spine surgery, Fineberg et al. found an overall incidence rate of post-operative delirium to be 8.4 events per 1000 and that older age (65 years old) was an independent predictor
http://dx.doi.org/10.1016/j.jocn.2017.02.040 0967-5868/Ó 2017 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Elsamadicy AA et al. Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (65 years old): A study of 453 consecutive elderly spine surgery patients. J Clin Neurosci (2017), http://dx.doi.org/10.1016/j. jocn.2017.02.040
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Table 1 Preoperative baseline variables for all patients. Variable
Non-Delirium (n = 436)
Delirium (n = 17)
p-Value
Preoperative Baseline Variables Male (%) White (%) Age at Surgery (Years) BMI (kg/m2) Diabetes (%) Smoker (%) COPD (%) CHF (%) CAD (%) AFib (%) HTN (%) Hypercholesterolemia
46.56 83.46 72.46 ± 5.78 28.38 ± 5.55 19.95 11.70 2.98 5.505 19.04 8.26 66.97 13.76
47.06 88.24 74.35 ± 5.02 28.86 ± 8.63 23.53 0.00 5.88 17.65 41.18 17.65 47.06 23.53
0.96 0.97 0.14 0.82 0.75 0.23 0.41 0.06 0.05 0.17 0.11 0.27
Operative Variables Median # of Fusion Levels [IQR] Operative Time (min) EBL (mL) UOP
2[1–4] 233.13 ± 110.26 599.53 ± 953.07 582.99 ± 486.344
3[2–6] 258.41 ± 81.23 1150.00 ± 1706.82 786.56 ± 606.86
0.08 0.23 0.21 0.20
Postoperative Variables LOS (Days) UTI (%) Pneumonia (%) Deep Surgical Site Infection (%) Superficial Surgical Site Infection (%) Other Infection (%) Sepsis Acute Renal Failure (%) DVT (%) PE (%) MI (%) Cardio Pulmonary Arrest (%) 30-Day Readmission rate (%)
5.70 ± 6.33 11.70 3.67 2.75 1.15 8.72 3.44 0.69 0.23 0.92 3.44 0.92 11.01
10.47 ± 6.65 47.06 11.76 11.76 11.76 23.53 5.88 0.00 5.88 5.88 5.88 0.00 41.18
0.009 0.0005 0.14 0.09 0.02 0.06 0.46 0.73 0.07 0.17 0.46 0.69 0.002
[10]. However, the effects of post-operative delirium on 30-day readmission rates in the elderly remain relatively unknown. The aim of this is to determine if post-operative delirium in the elderly is an independent risk factor for 30-day hospital readmission after spine surgery.
2. Methods In this retrospective study, 453 medical records of consecutive elderly (65 years old) patients undergoing spine surgery at Duke University Medical Center from 2008 to 2010 were reviewed. Institutional Review Board approval was obtained prior to study initiation. We identified 17 (3.75%) patients who experienced postoperative delirium according to DSM-V criteria (Non-Delirium: 436, Delirium: 17). We identified all unplanned readmissions within 30 days of discharge after index spine surgery. Demographic variables evaluated included patient age, gender, race and Body Mass Index (BMI). Co-morbidities included diabetes, chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), coronary artery disease (CAD), atrial fibrillation (AFib), hypertension (HTN), hypercholesterolemia, and smoking status. Preoperative psychiatric history and home-medication use were evaluated for patients who experienced post-operative delirium. Operative variables included number of vertebral levels involved, length of operation, estimated blood loss (EBL), and urinary output (UOP). Post-operative complications included length of hospital stay (LOS), urinary tract infection (UTI), pneumonia, deep and superficial surgical site infections (SSI), sepsis, acute renal failure (ARF), deep venous thrombosis (DVT), pulmonary embolism (PE), myocardial infarction (MI), cardio-pulmonary arrest, and 30-day readmission rate. For patients who experienced post-operative
delirium, the number of post-operative days to delirium and treatment plan were recorded. Parametric data were expressed as means ± standard deviation (SD) and compared using the Student’s t-test. Nonparametric data were expressed as median [interquartile range] and compared via the Mann–Whitney U test. Nominal data were compared with the Chi-square test. Relationship between independent variables and 30-day readmission rates was assessed using a multivariate logistic regression model. All tests were two sided and were statistically significant if the p-value was less than 0.05. Statistical analysis was performed using JMP-12 by SAS. 3. Results 453 elderly (65 years old) patients (Non-Delirium cohort: n = 436, Delirium cohort: n = 17) were included in this study. The proportion of men (46.56% vs. 47.06%, p = 0.96) and white (83.46% vs. 88.24%, p = 0.97) patients were similar between nondelirium and delirium cohorts, respectively, Table 1. There was no significant difference in age between both cohorts (NonDelirium cohort: 72.46 ± 5.78 years vs. Delirium cohort: 74.35 ± 5.02 years, p = 0.14), Table 1. No significant differences in BMI between both groups were observed (Non-Delirium cohort: 28.38 ± 5.55 kg/ m2 vs. Delirium cohort: 28.86 ± 8.63 kg/m2, p = 0.82), Table 1. There were no significant differences between both groups in the prevalence of other co-morbidities such diabetes, COPD, CHF, CAD, AFib, hypercholesterolemia and smoking status, Table 1. The mean ± SD length of operation (min) for the Non-Delirium and Delirium-cohort was 233.13 ± 110.26 min and 258.41 ± 81.23 min (p = 0.23), respectively, Table 1. The mean ± SD estimated blood loss (mL) for the Non-Delirium and Deliriumcohort was 599.53 ± 953.07 mL and 1150.00 ± 1706.82 mL (p = 0.21), respectively, Table 1. The mean ± SD intra-operative
Please cite this article in press as: Elsamadicy AA et al. Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (65 years old): A study of 453 consecutive elderly spine surgery patients. J Clin Neurosci (2017), http://dx.doi.org/10.1016/j. jocn.2017.02.040
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urine output (mL) for the Non-Delirium and Delirium-cohort was 582.99 ± 486.344 mL and 786.56 ± 606.86 mL (p = 0.20), respectively, Table 1. There was no significant difference in the median number of levels operated, p = 0.48, Table 1.
Table 3 Multivariate analysis and Odds Ratio (OR) of Independent predictors of 30-Day readmission after spine surgery in the elderly.
3.1. Post-operative complication profile and 30-day readmission rates Patients experiencing post-operative delirium had a significantly longer LOS compared to patients that did not (NonDelirium cohort: 5.70 ± 6.33 days vs. Delirium cohort: 10.47 ± 6.65 days, p = 0.009), Table 1. Delirium patients also experienced higher rates of UTI (47.06% vs. 11.70%, p = 0.0005) and superficial SSI (11.76% vs. 1.15%, p = 0.02) than the non-delirium patients, Table 1. The prevalence of other post-operative complications was similar between both cohorts (Non-Delirium cohort vs. Delirium cohort): Pneumonia (3.67% vs. 11.76%, p = 0.14), deep SSI (2.75% vs. 1 l.76%, p = 0.09), other infections (8.72% vs. 23.53%, p = 0.06), sepsis (3.44% vs. 5.88%, p = 0.46), ARF (0.69% vs. 0%, p = 0.73), DVT (0.23% vs. 5.88%, p = 0.17), PE (0.92% vs. 5.88%, p = 0.46), MI (3.44% vs 5.88%, p = 0.46), and cardio-pulmonary arrest (0.92% vs. 0%, p = 0.69), Table 1. There was a significant difference in 30-day readmission rates between both groups, with delirium patients having an increased rate compared to nondelirium patients (Delirium cohort: 41.18%% vs. Non-Depressed cohort: 11.01%, p = 0.03), Table 1.
*
Variable
Coefficient
OR
p-Value
Gender Age at Surgery BMI Smoker COPD CHF CAD HTN Fusion Levels Operative Time Length of Stay Post-Op Delirium Post-Op UTI Post-Op Pneumonia
0.1298 0.0099 0.0025 0.2042 0.7813 0.4279 0.1367 0.5898 0.0770 0.0045 0.0878 1.1273 0.4379 1.1893
0.77 0.99 1.00 1.50 4.77 0.42 0.76 3.25 1.08 1.00 0.92 9.53 2.40 10.79
0.42 0.75 0.93 0.41 0.05 0.24 0.52 0.001* 0.20 0.006* 0.02* 0.0009* 0.05 0.002*
Represents statistical significance of p < 0.05.
tion (17.64%), Table 2. The mean ± SD post-operative to delirium was 5.88 ± 7.61 days, Table 2. The most common reason for 30day hospital readmission was altered mental status (57.14%), followed by wound infection (14.28%), pain (14.28%), and UTI (14.28%), Table 2. 3.3. 30-day readmission independent predictors
3.2. Post-operative delirium cohort pre- and post-operative psychiatric characteristics, and causes of 30-day readmission The preoperative psychiatric disorders of the delirium cohort (n = 17) included depression (35.29%) and anxiety (23.53%), with no patient with a history of dementia or other psychiatric illnesses, Table 2. The home-use psychiatric medications included sertraline (17.65%), duloxetine (11.65%), alprazolam (5.88%), and clonazepam (5.88%) with the majority of patients not taking a prescribed psychiatric medication (70.58%), Table 2. Treatment medications and modalities for the post-operative delirium consisted of lorazepam (17.65%), haloperidol (11.76%), risperidone (11.76%), naloxone (5.88%), discontinuing narcotic medication (29.4%), and reorientaTable 2 Preoperative psychiatric disorder diagnosis and home medications, treatment and days from OR to Post-Op Delirium, and causes of 30-Day readmission. Variable
Delirium (n = 17)
Preoperative Psychiatric Disorder Depression (%) 35.29 Anxiety (%) 23.53 Dementia (%) 0% Other Psychiatric Illness (%) 0% Preoperative Psychiatric Home Medications Sertraline (%) 17.65 Duloxetine (%) 11.65 Alprazolam (%) 5.88 Clonazepam (%) 5.88 No Psychiatric Medication (%) 70.58 Treatment and Days to Post-Op Delirium Lorazepam (%) 17.65 Haloperidol (%) 11.76 Risperidone (%) 11.76 Naloxone (%) 5.88 Discontinued Narcotic (%) 29.4 Reorientation (%) 17.64 Days to Post-op Delirium 5.88 ± 7.61 Causes of 30-Day Readmission (n = 7) Altered Mental Status (%) 57.14 Pain (%) 14.28 Wound Infection (%) 14.28 UTI (%) 14.28
In a multivariate binary logistic regression analysis preoperative hypertension (p = 0.001), length of operation (p = 0.006), post-operative delirium (p = 0.0009), and pneumonia (p = 0.002) were independent predictors of readmission within 30-days of hospital discharge, Table 3. Patient age, gender, BMI, smoking, COPD, CHF, CAD, Fusion levels, and post-operative UTI were not statistically significant independent predictors of 30-day readmission. Furthermore, post-operative delirium has an odds-ratio of 9.5 in respect to predicting a 30-day readmission. 4. Discussion In this retrospective study of consecutive elderly (65 years old) patients undergoing spine surgery, we demonstrated that post-operative delirium in the elderly is an independent risk factor for 30-day hospital readmission after spine surgery. Furthermore, we found that altered mental status was the most common reason for 30-day readmission. Previous studies have associated post-operative delirium in elderly patients with increased incidence of post-operative complications and inferior short- and long-term surgical outcomes. In a prospective study of 232 elderly patients undergoing a major elective surgery, Raats et al. demonstrated that post-operative delirium was significantly associated with an increase in length of hospital stay, mortality rate, and adverse events [11]. Analogously, in a study of 144 elderly patients undergoing a major surgery, Robinson et al. found that postoperative delirium was significantly associated with increased length of hospital stay, post-discharge institutionalization, and 6-month mortality rates [12]. Moreover, the authors calculated the average time to onset to be 2.1 ± 0.9 days; while our study patients had a longer time to onset being 5.88 ± 7.61 days [12]. In another retrospective study of 656 patients who underwent cardiac surgery, Mangusan et al. demonstrated that post-operative delirium was associated with an increase in length of hospital stay, prevalence of falls, and need for home health if discharged home [13]. Similarly, in a prospective study of 562 surgical intensive care unit patients, Abelha et al. showed that post-operative delirium was an independent risk
Please cite this article in press as: Elsamadicy AA et al. Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (65 years old): A study of 453 consecutive elderly spine surgery patients. J Clin Neurosci (2017), http://dx.doi.org/10.1016/j. jocn.2017.02.040
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factor for becoming dependent on personal activities for daily living and was significantly associated with increased inpatient and 6-month mortality rates [14]. Furthermore, patients who experienced postoperative delirium showed a greater decline in short form-36 (SF-36) domains after discharge when compared to patients without postoperative delirium, which included: physical function, vitality, and social function [14]. Analogous to these studies, our study demonstrated that elderly patients experiencing post-operative delirium had an increased length of hospital stay and rate of UTIs, compared to elderly patients who did not experience post-operative delirium. While there have been many studies associating postoperative delirium with inferior surgical outcomes, there are only a few studies associating it with increased 30-day readmission rates. In a prospective study of 566 elderly patients who underwent an elective major surgery, Gleason et al. demonstrated that post-operative delirium without major post-operative complications was significantly associated with not only increased length of hospital stay, but also 30-day readmissions [15]. Furthermore, the authors concluded that delirium has a greater effect on the elderly patients than other major complications in regards to length of hospital stay and 30-day readmission rates [15]. Similarly, in a retrospective study of 49 elderly patients who underwent radical cystectomy, Large et al. found that patients who experienced postoperative delirium were more likely to be readmitted (odds ratio 10.7) and undergo reoperation (odds ratio 9.2) [16]. Analogously to these studies, our study demonstrated that elderly patients experiencing post-operative delirium have significantly higher 30-day readmission rates and is an independent risk factor for 30-day readmission (odds ratio 9.53). Postoperative delirium has a significant economic burden on our health system. In a recent study of 66 patients undergoing coronary artery bypass surgery or valve operations, Brown et al. demonstrated that patients who experience post-operative delirium have a significantly higher median hospital charge compared to patients who do not experience post-operative delirium ($51,805 vs. $35,748, respectively) [17]. Similarly, in a study of 242 elderly patients who underwent hip fracture surgery, Zywiel et al. found that $961,131 (Canadian dollars) was spent on care costs attributable to post-operative delirium [18]. In Fineberg et al.’s retrospective study of the of 578,457 patients who underwent lumbar decompression and lumbar fusion, the authors demonstrated that the overall costs for patients with delirium were greater than that of patients without delirium ($29,970 vs. $16,578, respectively) with an average cost increase of $13,392 [10]. Therefore, providing preventative measures of postoperative delirium is essential to lessen the soaring health care costs attributable to post-operative delirium. Overall, post-operative delirium is an oftentimes-misdiagnosed independent risk factor for 30-day hospital readmission in the elderly. Importantly, it has a significant burden on the healthcare system. In our study, we found that discontinuing the patients’ narcotic medication, patient reorientation, and initiation of lorazapam were the most frequent employed treatment methods for the post-operative delirium patients. There is still no clear evidence in the role of medications, such as antipsychotics, in prevention of post-operative delirium [19]. However, there is supporting evidence that demonstrate a multi-component intervention being effective [19]. Further studies are necessary to identify preventable measures of post-operative delirium in the elderly in order to shorten length of hospital stay, reduce rates of 30-day readmission, and decrease health care costs; while, ultimately improving patient care. This study has limitations, ensuing possible implications for its interpretation. The severity of the post-operative delirium was not
known for this study, which could have introduced a selection bias. Furthermore, the pre, peri-, and post-operative variables were retrospectively collected and analyzed for the purposes of this study, therefore are subject to the weaknesses of a retrospective analysis. Additionally, the duration of symptoms post-operatively were not collected and therefore are also subject to selection bias. Despite these limitations, this study has demonstrated that postoperative delirium serves as an independent risk factor for 30day readmission. 5. Conclusion Our study suggests that elderly patients experiencing postoperative delirium after spine surgery is an independent risk factor for unplanned readmission within 30-days of discharge. Preventable measures and early awareness of post-operative delirium in the elderly is may help reduce readmission rates. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. References [1] Jencks SF, Williams MV, Coleman EA. Rehospitalizations among patients in the medicare fee-for-service program. New Engl J Med 2009;360(14):1418–28. [2] US Department of Health and Human Services. New HHS data shows major strides made in patient safety lticas W,DC: Department of Health and Human Services, May 7, 2014.http://innovation.cms.gov/Files/reports/patient-safetyresults.pdf. Accessed March 26, 2016. In. [3] Boozary AS, Manchin 3rd J, Wicker RF. The medicare hospital readmissions reduction program: time for reform. JAMA 2015;314(4):347–8. [4] Rudolph JL, Marcantonio ER. Review articles: postoperative delirium: acute change with long-term implications. Anesth Analg 2011;112(5):1202–11. [5] Rudolph JL, Jones RN, Rasmussen LS, et al. Independent vascular and cognitive risk factors for postoperative delirium. Am J Med 2007;120(9):807–13. [6] Martin BJ, Buth KJ, Arora RC, et al. Delirium as a predictor of sepsis in postcoronary artery bypass grafting patients: a retrospective cohort study. Critical Care 2010;14(5):R171. [7] Leonard M, McInerney S, McFarland J, et al. Comparison of cognitive and neuropsychiatric profiles in hospitalised elderly medical patients with delirium, dementia and comorbid delirium-dementia. BMJ Open 2016;6(3): e009212. [8] Collins N, Blanchard MR, Tookman A, et al. Detection of delirium in the acute hospital. Age Ageing 2010;39(1):131–5. [9] Seo JS, Park SW, Lee YS, et al. Risk factors for delirium after spine surgery in elderly patients. J Korean Neurosurg Soc 2014;56(1):28–33. [10] Fineberg SJ, Nandyala SV, Marquez-Lara A, et al. Incidence and risk factors for postoperative delirium after lumbar spine surgery. Spine 2013;38(20):1790–6. [11] Raats JW, van Eijsden WA, Crolla RM, et al. Risk factors and outcomes for postoperative delirium after major surgery in elderly patients. PLoS One 2015;10(8):e0136071. [12] Robinson TN, Raeburn CD, Tran ZV, et al. Postoperative delirium in the elderly: risk factors and outcomes. Annal Surg 2009;249(1):173–8. [13] Mangusan RF, Hooper V, Denslow SA, et al. Outcomes associated with postoperative delirium after cardiac surgery. Am J Critical Care 2015;24 (2):156–63. [14] Abelha FJ, Luis C, Veiga D, et al. Outcome and quality of life in patients with postoperative delirium during an ICU stay following major surgery. Critical Care 2013;17(5):R257. [15] Gleason LJ, Schmitt EM, Kosar CM, et al. Effect of delirium and other major complications on outcomes after elective surgery in older adults. JAMA Surg 2015;150(12):1134–40. [16] Large MC, Reichard C, Williams JT, et al. Incidence, risk factors, and complications of postoperative delirium in elderly patients undergoing radical cystectomy. Urology 2013;81(1):123–8. [17] Brown CHT, Laflam A, Max L, et al. The impact of delirium after cardiac surgical procedures on postoperative resource use. Ann Thoracic Surg 2016. [18] Zywiel MG, Hurley RT, Perruccio AV, et al. Health economic implications of perioperative delirium in older patients after surgery for a fragility hip fracture. J Bone Joint Surg Am 2015;97(10):829–36. [19] Siddiqi N, Harrison JK, Clegg A, et al. Interventions for preventing delirium in hospitalised non-ICU patients. Cochrane Database System Rev 2016;3. CD005563.
Please cite this article in press as: Elsamadicy AA et al. Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (65 years old): A study of 453 consecutive elderly spine surgery patients. J Clin Neurosci (2017), http://dx.doi.org/10.1016/j. jocn.2017.02.040
Contents lists available at ScienceDirect
Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn
Case study
Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (65 years old): A study of 453 consecutive elderly spine surgery patients Aladine A. Elsamadicy, Timothy Y. Wang, Adam G. Back, Emily Lydon, Gireesh B. Reddy, Isaac O. Karikari, Oren N. Gottfried ⇑ Department of Neurosurgery, Duke University Medical Center, Durham, NC, United States
a r t i c l e
i n f o
Article history: Received 30 November 2016 Accepted 12 February 2017 Available online xxxx Keywords: Delirium 30-Day readmission Spine surgery
a b s t r a c t In the last decade, costs of U.S. healthcare expenditures have been soaring, with billions of dollars spent on hospital readmissions. Identifying causes and risk factors can reduce soaring readmission rates and help lower healthcare costs. The aim of this is to determine if post-operative delirium in the elderly is an independent risk factor for 30-day hospital readmission after spine surgery. The medical records of 453 consecutive elderly (65 years old) patients undergoing spine surgery at Duke University Medical Center from 2008 to 2010 were reviewed. We identified 17 (3.75%) patients who experienced postoperative delirium according to DSM-V criteria. Patient demographics, comorbidities, and postoperative complication rates were collected for each patient. Elderly patients experiencing postoperative delirium had an increased length of hospital stay (10.47 days vs. 5.70 days, p = 0.009). Complication rates were similar between the cohorts with the post-operative delirium patients having increased UTI and superficial surgical site infections. In total, 12.14% of patients were re-admitted within 30-days of discharge, with post-operative delirium patients experiencing approximately a 4-fold increase in 30-day readmission rates (Delirium: 41.18% vs. No Delirium: 11.01%, p = 0.002). In a multivariate logistic regression analysis, post-operative delirium is an independent predictor of 30-day readmission after spine surgery in the elderly (p = 0.03). Elderly patients experiencing post-operative delirium after spine surgery is an independent risk factor for unplanned readmission within 30-days of discharge. Preventable measures and early awareness of post-operative delirium in the elderly may help reduce readmission rates. Ó 2017 Elsevier Ltd. All rights reserved.
1. Introduction In the last decade, costs of U.S. healthcare expenditures have dramatically increased, with billions of dollars spent on hospital readmissions. Centers for Medicare & Medicaid Services (CMS) estimates that in 2004, over $17 billion was spent on potentially preventable, unplanned readmissions [1]. In 2013, approximately 18% of Medicare patients were readmitted to the hospital within 30 days, amounting to almost $26 billion billed towards Medicare [2,3]. Under the Patient Protection and Affordable Care Act, the Hospital Readmissions Reduction Program (HRRP) allows for CMS to penalize hospitals on Medicare reimbursements for 30-day readmission rates [3]. As a result, hospital administration now ⇑ Corresponding author at: Department of Neurosurgery, Duke University Medical Center, Duke South Zone Blue, Durham, NC 27705, United States. E-mail address: [email protected] (O.N. Gottfried).
tracks 30-day readmission rates as a metric of clinical performance and quality of care. Identifying causes and risk factors of 30-day readmission in the elderly population is necessary to reduce soaring readmission rates and healthcare costs. Post-operative delirium is a risk factor that has been associated with increased in-hospital mortality, complications, and length of hospital stay after surgery [4–6]. Hospitalized elderly patients have an increased susceptibility to neurocognitive disorders, such as delirium and dementia, which are frequently overlooked and commonly misdiagnosed [7,8]. Recently, there has been an increase in elderly patients undergoing elective spine surgery, as well as increased rates of postoperative delirium following spine surgery [9]. In a retrospective study of 578,457 patients who underwent lumbar spine surgery, Fineberg et al. found an overall incidence rate of post-operative delirium to be 8.4 events per 1000 and that older age (65 years old) was an independent predictor
http://dx.doi.org/10.1016/j.jocn.2017.02.040 0967-5868/Ó 2017 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Elsamadicy AA et al. Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (65 years old): A study of 453 consecutive elderly spine surgery patients. J Clin Neurosci (2017), http://dx.doi.org/10.1016/j. jocn.2017.02.040
2
A.A. Elsamadicy et al. / Journal of Clinical Neuroscience xxx (2017) xxx–xxx
Table 1 Preoperative baseline variables for all patients. Variable
Non-Delirium (n = 436)
Delirium (n = 17)
p-Value
Preoperative Baseline Variables Male (%) White (%) Age at Surgery (Years) BMI (kg/m2) Diabetes (%) Smoker (%) COPD (%) CHF (%) CAD (%) AFib (%) HTN (%) Hypercholesterolemia
46.56 83.46 72.46 ± 5.78 28.38 ± 5.55 19.95 11.70 2.98 5.505 19.04 8.26 66.97 13.76
47.06 88.24 74.35 ± 5.02 28.86 ± 8.63 23.53 0.00 5.88 17.65 41.18 17.65 47.06 23.53
0.96 0.97 0.14 0.82 0.75 0.23 0.41 0.06 0.05 0.17 0.11 0.27
Operative Variables Median # of Fusion Levels [IQR] Operative Time (min) EBL (mL) UOP
2[1–4] 233.13 ± 110.26 599.53 ± 953.07 582.99 ± 486.344
3[2–6] 258.41 ± 81.23 1150.00 ± 1706.82 786.56 ± 606.86
0.08 0.23 0.21 0.20
Postoperative Variables LOS (Days) UTI (%) Pneumonia (%) Deep Surgical Site Infection (%) Superficial Surgical Site Infection (%) Other Infection (%) Sepsis Acute Renal Failure (%) DVT (%) PE (%) MI (%) Cardio Pulmonary Arrest (%) 30-Day Readmission rate (%)
5.70 ± 6.33 11.70 3.67 2.75 1.15 8.72 3.44 0.69 0.23 0.92 3.44 0.92 11.01
10.47 ± 6.65 47.06 11.76 11.76 11.76 23.53 5.88 0.00 5.88 5.88 5.88 0.00 41.18
0.009 0.0005 0.14 0.09 0.02 0.06 0.46 0.73 0.07 0.17 0.46 0.69 0.002
[10]. However, the effects of post-operative delirium on 30-day readmission rates in the elderly remain relatively unknown. The aim of this is to determine if post-operative delirium in the elderly is an independent risk factor for 30-day hospital readmission after spine surgery.
2. Methods In this retrospective study, 453 medical records of consecutive elderly (65 years old) patients undergoing spine surgery at Duke University Medical Center from 2008 to 2010 were reviewed. Institutional Review Board approval was obtained prior to study initiation. We identified 17 (3.75%) patients who experienced postoperative delirium according to DSM-V criteria (Non-Delirium: 436, Delirium: 17). We identified all unplanned readmissions within 30 days of discharge after index spine surgery. Demographic variables evaluated included patient age, gender, race and Body Mass Index (BMI). Co-morbidities included diabetes, chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), coronary artery disease (CAD), atrial fibrillation (AFib), hypertension (HTN), hypercholesterolemia, and smoking status. Preoperative psychiatric history and home-medication use were evaluated for patients who experienced post-operative delirium. Operative variables included number of vertebral levels involved, length of operation, estimated blood loss (EBL), and urinary output (UOP). Post-operative complications included length of hospital stay (LOS), urinary tract infection (UTI), pneumonia, deep and superficial surgical site infections (SSI), sepsis, acute renal failure (ARF), deep venous thrombosis (DVT), pulmonary embolism (PE), myocardial infarction (MI), cardio-pulmonary arrest, and 30-day readmission rate. For patients who experienced post-operative
delirium, the number of post-operative days to delirium and treatment plan were recorded. Parametric data were expressed as means ± standard deviation (SD) and compared using the Student’s t-test. Nonparametric data were expressed as median [interquartile range] and compared via the Mann–Whitney U test. Nominal data were compared with the Chi-square test. Relationship between independent variables and 30-day readmission rates was assessed using a multivariate logistic regression model. All tests were two sided and were statistically significant if the p-value was less than 0.05. Statistical analysis was performed using JMP-12 by SAS. 3. Results 453 elderly (65 years old) patients (Non-Delirium cohort: n = 436, Delirium cohort: n = 17) were included in this study. The proportion of men (46.56% vs. 47.06%, p = 0.96) and white (83.46% vs. 88.24%, p = 0.97) patients were similar between nondelirium and delirium cohorts, respectively, Table 1. There was no significant difference in age between both cohorts (NonDelirium cohort: 72.46 ± 5.78 years vs. Delirium cohort: 74.35 ± 5.02 years, p = 0.14), Table 1. No significant differences in BMI between both groups were observed (Non-Delirium cohort: 28.38 ± 5.55 kg/ m2 vs. Delirium cohort: 28.86 ± 8.63 kg/m2, p = 0.82), Table 1. There were no significant differences between both groups in the prevalence of other co-morbidities such diabetes, COPD, CHF, CAD, AFib, hypercholesterolemia and smoking status, Table 1. The mean ± SD length of operation (min) for the Non-Delirium and Delirium-cohort was 233.13 ± 110.26 min and 258.41 ± 81.23 min (p = 0.23), respectively, Table 1. The mean ± SD estimated blood loss (mL) for the Non-Delirium and Deliriumcohort was 599.53 ± 953.07 mL and 1150.00 ± 1706.82 mL (p = 0.21), respectively, Table 1. The mean ± SD intra-operative
Please cite this article in press as: Elsamadicy AA et al. Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (65 years old): A study of 453 consecutive elderly spine surgery patients. J Clin Neurosci (2017), http://dx.doi.org/10.1016/j. jocn.2017.02.040
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urine output (mL) for the Non-Delirium and Delirium-cohort was 582.99 ± 486.344 mL and 786.56 ± 606.86 mL (p = 0.20), respectively, Table 1. There was no significant difference in the median number of levels operated, p = 0.48, Table 1.
Table 3 Multivariate analysis and Odds Ratio (OR) of Independent predictors of 30-Day readmission after spine surgery in the elderly.
3.1. Post-operative complication profile and 30-day readmission rates Patients experiencing post-operative delirium had a significantly longer LOS compared to patients that did not (NonDelirium cohort: 5.70 ± 6.33 days vs. Delirium cohort: 10.47 ± 6.65 days, p = 0.009), Table 1. Delirium patients also experienced higher rates of UTI (47.06% vs. 11.70%, p = 0.0005) and superficial SSI (11.76% vs. 1.15%, p = 0.02) than the non-delirium patients, Table 1. The prevalence of other post-operative complications was similar between both cohorts (Non-Delirium cohort vs. Delirium cohort): Pneumonia (3.67% vs. 11.76%, p = 0.14), deep SSI (2.75% vs. 1 l.76%, p = 0.09), other infections (8.72% vs. 23.53%, p = 0.06), sepsis (3.44% vs. 5.88%, p = 0.46), ARF (0.69% vs. 0%, p = 0.73), DVT (0.23% vs. 5.88%, p = 0.17), PE (0.92% vs. 5.88%, p = 0.46), MI (3.44% vs 5.88%, p = 0.46), and cardio-pulmonary arrest (0.92% vs. 0%, p = 0.69), Table 1. There was a significant difference in 30-day readmission rates between both groups, with delirium patients having an increased rate compared to nondelirium patients (Delirium cohort: 41.18%% vs. Non-Depressed cohort: 11.01%, p = 0.03), Table 1.
*
Variable
Coefficient
OR
p-Value
Gender Age at Surgery BMI Smoker COPD CHF CAD HTN Fusion Levels Operative Time Length of Stay Post-Op Delirium Post-Op UTI Post-Op Pneumonia
0.1298 0.0099 0.0025 0.2042 0.7813 0.4279 0.1367 0.5898 0.0770 0.0045 0.0878 1.1273 0.4379 1.1893
0.77 0.99 1.00 1.50 4.77 0.42 0.76 3.25 1.08 1.00 0.92 9.53 2.40 10.79
0.42 0.75 0.93 0.41 0.05 0.24 0.52 0.001* 0.20 0.006* 0.02* 0.0009* 0.05 0.002*
Represents statistical significance of p < 0.05.
tion (17.64%), Table 2. The mean ± SD post-operative to delirium was 5.88 ± 7.61 days, Table 2. The most common reason for 30day hospital readmission was altered mental status (57.14%), followed by wound infection (14.28%), pain (14.28%), and UTI (14.28%), Table 2. 3.3. 30-day readmission independent predictors
3.2. Post-operative delirium cohort pre- and post-operative psychiatric characteristics, and causes of 30-day readmission The preoperative psychiatric disorders of the delirium cohort (n = 17) included depression (35.29%) and anxiety (23.53%), with no patient with a history of dementia or other psychiatric illnesses, Table 2. The home-use psychiatric medications included sertraline (17.65%), duloxetine (11.65%), alprazolam (5.88%), and clonazepam (5.88%) with the majority of patients not taking a prescribed psychiatric medication (70.58%), Table 2. Treatment medications and modalities for the post-operative delirium consisted of lorazepam (17.65%), haloperidol (11.76%), risperidone (11.76%), naloxone (5.88%), discontinuing narcotic medication (29.4%), and reorientaTable 2 Preoperative psychiatric disorder diagnosis and home medications, treatment and days from OR to Post-Op Delirium, and causes of 30-Day readmission. Variable
Delirium (n = 17)
Preoperative Psychiatric Disorder Depression (%) 35.29 Anxiety (%) 23.53 Dementia (%) 0% Other Psychiatric Illness (%) 0% Preoperative Psychiatric Home Medications Sertraline (%) 17.65 Duloxetine (%) 11.65 Alprazolam (%) 5.88 Clonazepam (%) 5.88 No Psychiatric Medication (%) 70.58 Treatment and Days to Post-Op Delirium Lorazepam (%) 17.65 Haloperidol (%) 11.76 Risperidone (%) 11.76 Naloxone (%) 5.88 Discontinued Narcotic (%) 29.4 Reorientation (%) 17.64 Days to Post-op Delirium 5.88 ± 7.61 Causes of 30-Day Readmission (n = 7) Altered Mental Status (%) 57.14 Pain (%) 14.28 Wound Infection (%) 14.28 UTI (%) 14.28
In a multivariate binary logistic regression analysis preoperative hypertension (p = 0.001), length of operation (p = 0.006), post-operative delirium (p = 0.0009), and pneumonia (p = 0.002) were independent predictors of readmission within 30-days of hospital discharge, Table 3. Patient age, gender, BMI, smoking, COPD, CHF, CAD, Fusion levels, and post-operative UTI were not statistically significant independent predictors of 30-day readmission. Furthermore, post-operative delirium has an odds-ratio of 9.5 in respect to predicting a 30-day readmission. 4. Discussion In this retrospective study of consecutive elderly (65 years old) patients undergoing spine surgery, we demonstrated that post-operative delirium in the elderly is an independent risk factor for 30-day hospital readmission after spine surgery. Furthermore, we found that altered mental status was the most common reason for 30-day readmission. Previous studies have associated post-operative delirium in elderly patients with increased incidence of post-operative complications and inferior short- and long-term surgical outcomes. In a prospective study of 232 elderly patients undergoing a major elective surgery, Raats et al. demonstrated that post-operative delirium was significantly associated with an increase in length of hospital stay, mortality rate, and adverse events [11]. Analogously, in a study of 144 elderly patients undergoing a major surgery, Robinson et al. found that postoperative delirium was significantly associated with increased length of hospital stay, post-discharge institutionalization, and 6-month mortality rates [12]. Moreover, the authors calculated the average time to onset to be 2.1 ± 0.9 days; while our study patients had a longer time to onset being 5.88 ± 7.61 days [12]. In another retrospective study of 656 patients who underwent cardiac surgery, Mangusan et al. demonstrated that post-operative delirium was associated with an increase in length of hospital stay, prevalence of falls, and need for home health if discharged home [13]. Similarly, in a prospective study of 562 surgical intensive care unit patients, Abelha et al. showed that post-operative delirium was an independent risk
Please cite this article in press as: Elsamadicy AA et al. Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (65 years old): A study of 453 consecutive elderly spine surgery patients. J Clin Neurosci (2017), http://dx.doi.org/10.1016/j. jocn.2017.02.040
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factor for becoming dependent on personal activities for daily living and was significantly associated with increased inpatient and 6-month mortality rates [14]. Furthermore, patients who experienced postoperative delirium showed a greater decline in short form-36 (SF-36) domains after discharge when compared to patients without postoperative delirium, which included: physical function, vitality, and social function [14]. Analogous to these studies, our study demonstrated that elderly patients experiencing post-operative delirium had an increased length of hospital stay and rate of UTIs, compared to elderly patients who did not experience post-operative delirium. While there have been many studies associating postoperative delirium with inferior surgical outcomes, there are only a few studies associating it with increased 30-day readmission rates. In a prospective study of 566 elderly patients who underwent an elective major surgery, Gleason et al. demonstrated that post-operative delirium without major post-operative complications was significantly associated with not only increased length of hospital stay, but also 30-day readmissions [15]. Furthermore, the authors concluded that delirium has a greater effect on the elderly patients than other major complications in regards to length of hospital stay and 30-day readmission rates [15]. Similarly, in a retrospective study of 49 elderly patients who underwent radical cystectomy, Large et al. found that patients who experienced postoperative delirium were more likely to be readmitted (odds ratio 10.7) and undergo reoperation (odds ratio 9.2) [16]. Analogously to these studies, our study demonstrated that elderly patients experiencing post-operative delirium have significantly higher 30-day readmission rates and is an independent risk factor for 30-day readmission (odds ratio 9.53). Postoperative delirium has a significant economic burden on our health system. In a recent study of 66 patients undergoing coronary artery bypass surgery or valve operations, Brown et al. demonstrated that patients who experience post-operative delirium have a significantly higher median hospital charge compared to patients who do not experience post-operative delirium ($51,805 vs. $35,748, respectively) [17]. Similarly, in a study of 242 elderly patients who underwent hip fracture surgery, Zywiel et al. found that $961,131 (Canadian dollars) was spent on care costs attributable to post-operative delirium [18]. In Fineberg et al.’s retrospective study of the of 578,457 patients who underwent lumbar decompression and lumbar fusion, the authors demonstrated that the overall costs for patients with delirium were greater than that of patients without delirium ($29,970 vs. $16,578, respectively) with an average cost increase of $13,392 [10]. Therefore, providing preventative measures of postoperative delirium is essential to lessen the soaring health care costs attributable to post-operative delirium. Overall, post-operative delirium is an oftentimes-misdiagnosed independent risk factor for 30-day hospital readmission in the elderly. Importantly, it has a significant burden on the healthcare system. In our study, we found that discontinuing the patients’ narcotic medication, patient reorientation, and initiation of lorazapam were the most frequent employed treatment methods for the post-operative delirium patients. There is still no clear evidence in the role of medications, such as antipsychotics, in prevention of post-operative delirium [19]. However, there is supporting evidence that demonstrate a multi-component intervention being effective [19]. Further studies are necessary to identify preventable measures of post-operative delirium in the elderly in order to shorten length of hospital stay, reduce rates of 30-day readmission, and decrease health care costs; while, ultimately improving patient care. This study has limitations, ensuing possible implications for its interpretation. The severity of the post-operative delirium was not
known for this study, which could have introduced a selection bias. Furthermore, the pre, peri-, and post-operative variables were retrospectively collected and analyzed for the purposes of this study, therefore are subject to the weaknesses of a retrospective analysis. Additionally, the duration of symptoms post-operatively were not collected and therefore are also subject to selection bias. Despite these limitations, this study has demonstrated that postoperative delirium serves as an independent risk factor for 30day readmission. 5. Conclusion Our study suggests that elderly patients experiencing postoperative delirium after spine surgery is an independent risk factor for unplanned readmission within 30-days of discharge. Preventable measures and early awareness of post-operative delirium in the elderly is may help reduce readmission rates. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. References [1] Jencks SF, Williams MV, Coleman EA. Rehospitalizations among patients in the medicare fee-for-service program. New Engl J Med 2009;360(14):1418–28. [2] US Department of Health and Human Services. New HHS data shows major strides made in patient safety lticas W,DC: Department of Health and Human Services, May 7, 2014.http://innovation.cms.gov/Files/reports/patient-safetyresults.pdf. Accessed March 26, 2016. In. [3] Boozary AS, Manchin 3rd J, Wicker RF. The medicare hospital readmissions reduction program: time for reform. JAMA 2015;314(4):347–8. [4] Rudolph JL, Marcantonio ER. Review articles: postoperative delirium: acute change with long-term implications. Anesth Analg 2011;112(5):1202–11. [5] Rudolph JL, Jones RN, Rasmussen LS, et al. Independent vascular and cognitive risk factors for postoperative delirium. Am J Med 2007;120(9):807–13. [6] Martin BJ, Buth KJ, Arora RC, et al. Delirium as a predictor of sepsis in postcoronary artery bypass grafting patients: a retrospective cohort study. Critical Care 2010;14(5):R171. [7] Leonard M, McInerney S, McFarland J, et al. Comparison of cognitive and neuropsychiatric profiles in hospitalised elderly medical patients with delirium, dementia and comorbid delirium-dementia. BMJ Open 2016;6(3): e009212. [8] Collins N, Blanchard MR, Tookman A, et al. Detection of delirium in the acute hospital. Age Ageing 2010;39(1):131–5. [9] Seo JS, Park SW, Lee YS, et al. Risk factors for delirium after spine surgery in elderly patients. J Korean Neurosurg Soc 2014;56(1):28–33. [10] Fineberg SJ, Nandyala SV, Marquez-Lara A, et al. Incidence and risk factors for postoperative delirium after lumbar spine surgery. Spine 2013;38(20):1790–6. [11] Raats JW, van Eijsden WA, Crolla RM, et al. Risk factors and outcomes for postoperative delirium after major surgery in elderly patients. PLoS One 2015;10(8):e0136071. [12] Robinson TN, Raeburn CD, Tran ZV, et al. Postoperative delirium in the elderly: risk factors and outcomes. Annal Surg 2009;249(1):173–8. [13] Mangusan RF, Hooper V, Denslow SA, et al. Outcomes associated with postoperative delirium after cardiac surgery. Am J Critical Care 2015;24 (2):156–63. [14] Abelha FJ, Luis C, Veiga D, et al. Outcome and quality of life in patients with postoperative delirium during an ICU stay following major surgery. Critical Care 2013;17(5):R257. [15] Gleason LJ, Schmitt EM, Kosar CM, et al. Effect of delirium and other major complications on outcomes after elective surgery in older adults. JAMA Surg 2015;150(12):1134–40. [16] Large MC, Reichard C, Williams JT, et al. Incidence, risk factors, and complications of postoperative delirium in elderly patients undergoing radical cystectomy. Urology 2013;81(1):123–8. [17] Brown CHT, Laflam A, Max L, et al. The impact of delirium after cardiac surgical procedures on postoperative resource use. Ann Thoracic Surg 2016. [18] Zywiel MG, Hurley RT, Perruccio AV, et al. Health economic implications of perioperative delirium in older patients after surgery for a fragility hip fracture. J Bone Joint Surg Am 2015;97(10):829–36. [19] Siddiqi N, Harrison JK, Clegg A, et al. Interventions for preventing delirium in hospitalised non-ICU patients. Cochrane Database System Rev 2016;3. CD005563.
Please cite this article in press as: Elsamadicy AA et al. Post-operative delirium is an independent predictor of 30-day hospital readmission after spine surgery in the elderly (65 years old): A study of 453 consecutive elderly spine surgery patients. J Clin Neurosci (2017), http://dx.doi.org/10.1016/j. jocn.2017.02.040