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Resource utilization and its management in splenic trauma
The American Journal of Surgery 187 (2004) 713–719
Scientific paper
Resource utilization and its management in splenic trauma Amalia Cochran, M.D., M.A.a,b, N. Clay Mann, Ph.D., M.S.b, J. Michael Dean, M.D., M.B.A.b, Lawrence J. Cook, M.Stat.b, Richard G. Barton, M.D.a,* a
Department of Surgery, School of Medicine, University of Utah, 30 N. 1900 East, Room 3B110, Salt Lake City, UT 84312, USA b Intermountain Injury Control Research Center, Salt Lake City, UT, USA Manuscript received April 22, 2003; revised manuscript October 18, 2003
Abstract Background: This study compared resource utilization and its management for splenic injury at 2 level-I trauma centers and a pediatric referral center with other facilities in a state currently developing a trauma system. Methods: Management strategy, length of stay, and total charges for children were compared among the pediatric referral center, trauma centers, and other facilities. Adult management, length of stay, and total charges were compared between trauma centers and other facilities. Results: Nonoperative management was more frequent in children at the pediatric referral center than trauma centers or other facilities and was more common in adults at trauma centers than at other facilities. Mean length of stay and total charges for children were significantly greater at the pediatric referral center and trauma centers than at other facilities and for adults at trauma centers than at other facilities. Facility type was associated with length of stay and total charges when injury type and severity were controlled. Conclusions: Nonoperative management of splenic injury is more common at trauma centers, and splenic trauma management may be more costly at trauma centers. © 2004 Excerpta Medica, Inc. All rights reserved. Keywords: Probabilistic data linkage; Resource utilization; Splenic trauma
The spleen is the most commonly injured organ in patients sustaining blunt abdominal trauma [1]. Because of a perception of increased mortality with nonoperative management, splenic injury historically has been managed operatively. Research in the early to mid-20th century demonstrated a variety of immunologic functions of the spleen; this research provided the foundation for a clinical paradigm shift toward splenic preservation after traumatic injury. Pediatric surgeons initiated nonoperative management of splenic injury because children are at higher risk of overwhelming postsplenectomy sepsis than adults [2]. The successful pediatric experience with nonoperative management of splenic injury has been extended to the management of adult trauma patients. The application of nonoperative management has broadened significantly as trauma surgeons have recognized that most splenic injuries can be managed nonoperatively. This management trend is well documented in the trauma literature, which shows a consis-
tent increase in the rate of nonoperative management of splenic injury [3– 6]. The preponderance of studies demonstrates that blunt splenic injury in children is more likely to be managed nonoperatively at a dedicated pediatric facility than at other facilities [4,7,8]. However, 1 recent study showed that dedicated trauma surgeons can obtain a rate of nonoperative management similar to their pediatric surgical colleagues in the care of children with splenic injury [9]. Differences also exist between rural and urban facilities in the management of adults with splenic injuries [8]. In this study, we reviewed the management patterns of blunt splenic injury in a single state. Specifically, we compared the management of splenic injury at Utah’s 2 statedesignated level-I trauma centers and a regional pediatric referral facility with management at all other hospitals in Utah.
Resource utilization in splenic injury * Corresponding author. Tel.: ⫹1-801-581-4314; fax: ⫹1-801-5879149. E-mail address: [email protected]
Trauma centers and trauma systems clearly show improved clinical outcomes in critically injured trauma pa-
0002-9610/04/$ – see front matter © 2004 Excerpta Medica, Inc. All rights reserved. doi:10.1016/j.amjsurg.2003.10.021
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tients [10 –15]. However, the impact of trauma centers on the costs of trauma care remains unclear. The current political and economic milieu of health care demands that patients receive the best care available at the lowest cost. Resource utilization provides an important but seldom used means for evaluating cost-efficiency in trauma care. We identified only 1 published study examining resource utilization in the management of splenic injury [16]. Clancy et al [16] compared the impact of operative versus nonoperative management of splenic injury on length of stay and average hospital charges for adult patients at a single level-II trauma center. We are unaware of any study of resource utilization for splenic injury comparing level-I trauma centers with nondesignated facilities. Our study compared resource utilization in the management of splenic injury at state-designated level-I trauma centers, a regional pediatric referral facility, and all other hospitals in the state of Utah. Length of stay and total charges served as measures of resource utilization.
Methods Study design This study was a retrospective cohort analysis of resource utilization among patients with blunt splenic trauma managed at two level-I trauma centers or a regional pediatric referral center compared with other hospitals. We evaluated pediatric and adult patients separately because the rate of nonoperative management of splenic injury is generally much higher for children [6,17]. We compared management strategy, length of stay, and total charges for children with splenic injury between the regional pediatric referral center, the two level-I trauma centers, and all other hospitals. We also compared the level-I trauma centers with all other community-level hospitals using the same dependent variables for adults. Study population and data sources Utah is a largely rural state with 75% of the population concentrated in a 4-county area known as the Wasatch Front [18]. The Wasatch Front runs approximately 90 miles along the western edge of the Wasatch Mountains, extending from Ogden in the north to Provo in the south. Both of the state-designated level-I facilities and the pediatric referral facility are located in this area. Aside from these 3 facilities, no other hospitals in Utah are verified as trauma centers by the American College of Surgeons. The Utah emergency department (ED), hospital discharge, and death certificate databases for 1996 and 1997 were used in this analysis. The ED and hospital discharge databases were obtained from the Utah Health Data Committee/Office of Health Data Analysis. Appropriate data must be reported to these databases under state law. These
databases include demographic information, International Classification of Diseases-9 Clinical Modification (ICD-9 CM) codes, E-codes, billing information, and hospital charges. The Utah ED database includes patients who present to the ED and who are subsequently are discharged to home or who are transferred to another health care facility for inpatient care. Patients seen in the ED and subsequently admitted to the same facility are included only in the Utah hospital discharge database. We included only inpatient admissions in our analysis. The Utah death certificate database was obtained from the Bureau of Vital Statistics through the University of Utah Resource for Genetic and Epidemiologic Research. This database includes demographic information, up to 4 ICD-9 CM codes, and E-codes as appropriate. We included data from the vital statistics database for identification of 30-day mortality after hospital discharge. The University of Utah Institutional Review Board approved the use of these databases for the purposes of this study. Probabilistic linkage Probabilistic linkage is a technique that uses probability to link records from multiple data sources that apply to the same person or event. This methodology links records among ⱖ2 data sets through calculation of probability weights including adjustments for incomplete or missing data. Jaro [19] previously described computerized probabilistic linkage in some detail. CODES 2000 (Strategic Matching, Inc., Morrisonville, New York) was used to perform probabilistic linkage employing an iterative approach that mathematically links databases not originally designed for linkage. Probabilistic linkage of the ED, hospital discharge, and death certificate databases generated the data set used for statistical analysis. Probabilistic record linkage is accomplished by comparing data fields such as birth date or sex in 2 files. Comparison of numerous data fields leads to a judgment that 2 records refer to the same patient and should be linked. This judgment is based on the cumulative weight of agreement and disagreement among field values. The amount of information contained in a field is related to that field’s impact on the judgment process. For instance, agreement of the sex field alone would not provide sufficient weight to determine that 2 records refer to the same patient, but agreement on Social Security Number nearly guarantees that 2 records refer to the same patient. We performed a 1-to-1 linkage, meaning an individual ED record or death record was allowed to link to only 1 hospital discharge record. Variables included were date of hospital visit, patient date of birth, hospital code, county code, city code, sex, and age. The software cleared patients who were admitted to one hospital then transferred to another. Once we created the database linkage file, we limited the data set based on ICD-9 CM codes from the hospital
A. Cochran et al. / The American Journal of Surgery 187 (2004) 713–719
discharge database that were specific to internal injury to the spleen (865.0 to 865.1 with any fifth digit).
Table 1 Patient characteristics Characteristic
Pediatric patients (n ⫽ 159)
Adult patients (n ⫽ 305)
Sex (% male) Mean ⫾ SD age (years) Mean ⫾ SD ISS Multitrauma (%) Head injury (%) Rate of nonoperative management (%) Deaths (%)
66.0 12.3 ⫾ 4.2 16.1 ⫾ 12.4 45.3 20.7 80.5
64.9 35.9 ⫾ 17.4 21.8 ⫾ 12.7 74.7 14.4 54.1
Data definitions Several variables were generated from the data included in the linked file. ICDMAP-90 software (Johns Hopkins University and Tri-Analytics, Inc., Baltimore, Maryland) was used to calculate abbreviated injury scores (AIS) and the Injury Severity Score (ISS) for all patients included in the analysis. Nonoperative management was defined as the absence of the following ICD-9 CM procedure codes from a patient’s medical record: 41.4 (excision or destruction of lesion or tissue of spleen); 41.5 (total splenectomy); 41.95 (repair or plastic operations on the spleen); and 41.99 (other operations on the spleen). The hospital identification number was used to identify facility type as pediatric referral center, level-I trauma center, or other nondesignated facility. Multitrauma status was defined as any patient with ICD-9 CM codes inconsistent with the presence of isolated abdominal injury. Clinically significant head injury was defined as any patient with a head region AIS ⱖ3. Length of stay and total charges demonstrated nonnormal distributions and were therefore log-transformed for modeling purposes. Statistical analysis We designated patients ⬍18 years old as children for analysis purposes. The Student t test was used to compare the mean age and ISS of children treated at the pediatric referral center with those treated at the level-I trauma centers and all other facilities. Chi-square analyses compared the proportion of male patients, frequency of head injury, presence of isolated abdominal trauma, and the type of management strategy between children managed at the pediatric referral center, those treated at level-I facilities, and those treated elsewhere. The Kruskal-Wallis test was used to analyze the differences in median length of stay and hospital charges between the pediatric referral center, level-I centers, and all other facilities for children who sustained splenic trauma. Data for adult patients were analyzed using the Wilcoxon Rank Sum test comparing level-I trauma centers with all other hospitals. Log-transformed length of stay and total charges were employed as the dependent variables in analysis of variance (ANOVA) models that controlled for patient demographics, injury type, and injury severity. We created separate multivariable ANOVA models for children and adults.
Results One hundred fifty-nine children and 305 adults underwent inpatient management of splenic injury in the state of Utah during 1996 and 1997 (Table 1). The rate of nonoperative management of splenic injury was 81% for children
715
3.1
3.9
ISS ⫽ Injury Severity Score.
and 54% for adults. A greater proportion of adult patients were multitrauma patients, but relatively more children suffered head injuries. Twenty percent of adults sustained a pelvic fracture. Other common injuries in adults included spine fractures (14% of patients) and femur fractures (5% of patients). The mortality rates for patients with traumatic splenic injury were 3% for children and 4% for adults. Pediatric patients Children with splenic injury managed at the pediatric referral center showed several key differences from children managed at level-I facilities or other nondesignated hospitals (Table 2). Children treated at the pediatric referral facility were significantly younger than children treated at either level-I trauma centers or other facilities (P ⱕ0.001). Mean injury severity score of children treated at the pediatric referral center or the level-I trauma centers was significantly higher than that of children managed at other hospitals (P ⬍0.018). Children with head injury in conjunction with their splenic injury were significantly more likely to be treated at the pediatric referral center or the level-I trauma centers (P ⱕ0.001). The incidence of isolated abdominal injury was significantly lower at the pediatric referral center and the level-I trauma centers than at other facilities. Table 2 Pediatric demographic data: pediatric referral center versus level-I trauma centers versus all other facilities Demographic data
Mean ⫾ SD age (years) Sex (% male) Mean ⫾ SD ISS Head injury (%) Isolated abdominal trauma (%)
Pediatric referral center (n ⫽ 48)
Level-I trauma centers (n ⫽ 27)
All other (n ⫽ 84)
P value
9.0 ⫾ 4.4
15.4 ⫾ 2.4
13.1 ⫾ 3.4
ⱕ0.001
64.6 18.1 ⫾ 14.5 22.9 37.5
55.6 20.3 ⫾ 11.1 18.5 37.0
71.4 13.5 ⫾ 11.0 2.4 70.2
0.300 0.018 ⱕ0.001 ⱕ0.001
ISS ⫽ Injury Severity Score.
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Table 3 Pediatric management and resource utilization: pediatric referral center versus level-I trauma centers versus all other facilities
Table 5 Adult management and resource utilization: level I versus nontrauma centers
Management and Pediatric utilization referral center (n ⫽ 48)
Management and utilization
Level I trauma centers (n ⫽ 134)
All other facilities (n ⫽ 171)
Nonoperative management (%) Median LOS days (IQR) Median total charges $1000 (IQR)
61.2
48.5
Level-I trauma centers (n ⫽ 27)
All other (n ⫽ 84)
P value
Nonoperative 93.7 70.4 76.2 0.009 management (%) Median LOS days 5.0 (3.3–10) 5.0 (4.0–9.0) 4.0 (2.0–5.0) ⱕ0.001 (IQR) Median total 11.1 (5.4–23.1) 12.1 (6.5–43.3) 6.7 (4.5–9.9) ⱕ0.001 charges $1000 (IQR) IQR ⫽ interquartile range; LOS ⫽ length of stay.
Children treated at the pediatric referral center were significantly more likely to undergo nonoperative management of their splenic injury than were children treated at the level-I centers or other hospitals (94% vs. 70% vs. 76%, respectively; Table 3). The results demonstrated a longer median length of stay for patients managed at the pediatric referral center and the level-I trauma centers than for the children managed elsewhere (5 days vs. 5 days vs. 4 days, respectively; P ⱕ0.001). Significantly higher median total charges were also incurred at the pediatric referral facility and the level-I trauma centers than at other facilities in the management of pediatric trauma patients with splenic injury ($11,129 vs. $12,070 vs. $6,679, respectively; P ⱕ0.001). Adult patients Mean age, mean ISS, and gender distribution did not differ significantly between adult splenic injury patients treated at level-I trauma centers and those treated elsewhere (Table 4). The prevalence of head injury in conjunction with splenic injury was doubled in patients treated at level-I trauma centers versus those managed at nondesignated facilities. Only 13% of the patients treated for splenic injury at level-I trauma centers had isolated abdominal injuries versus 34% of the patients treated at other hospitals. Table 4 Adult demographic data: level-I versus nontrauma centers Demographic data
Level-I trauma centers (n ⫽ 134)
All other facilities (n ⫽ 171)
P value
Mean ⫾ SD age (years) Sex (% male) Mean ⫾ SD ISS Head injury (%) Isolated abdominal trauma (%)
37.0 ⫾ 16.8 63.4 22.6 ⫾ 12.5 20.0 13.4
35.0 ⫾ 17.8 66.7 21.3 ⫾ 12.9 10.6 34.5
0.330 0.556 0.357 0.024 ⱕ0.001
ISS ⫽ Injury Severity Score.
8.0 (5–12.2) 25.6 (14.4–49.8)
P value
0.027
6.0 (4.0–8.0)
ⱕ0.001
11.3 (7.7–20.1)
ⱕ0.001
Abbreviations as in Table 3.
Adults with splenic injury who received care at level-I trauma centers were more likely to undergo nonoperative management (61% vs. 48%, P ⫽ 0.027; Table 5). Median length of stay was 8 days at the level-I trauma centers and 6 days at other hospitals (P ⱕ0.001). Median total charges at the level-I centers were more than twice the charges at nondesignated facilities ($25,606 vs. $11,345; P ⱕ0.001). Multivariable analysis–resource utilization All of the children who died were treated at the pediatric referral center, resulting in a potential effect of these 5 children on statistical modeling of resource utilization (Table 6). Three of these children died during a 1-day length of stay, and 1 died during a 2-day length of stay. Perhaps most importantly, they all died as a result of traumatic brain injury. The paucity of these deaths makes it difficult to adequately model the impact of mortality, and we therefore excluded from subsequent analyses those children who died. Our concerns about the impact of mortality on modeling of resource utilization in children were also present for adults. We noted that 8 of the adults who died did so during the first 24 hours of their hospitalization, resulting in brief Table 6 Demographic and injury characteristics of deaths Characteristic
Children (n ⫽ 5)
Adults (n ⫽ 12)
Mean ⫾ SD age (years) Sex (% male) Mean ⫾ SD ISS Head injury (%) Multitrauma (%) Operative management of splenic injury (%) Management at pediatric referral center or level-I center (%) Median LOS days (IQR) Median total charges $1000 (IQR)
6.8 ⫾ 3.3 68 48.6 ⫾ 12.3 100 100 40.0
47.1 ⫾ 24.6 80 45.1 ⫾ 15.0 67.0 100 50.0
100
1.5 (1.0–4.5) 23.4 (16.6–41.9)
Abbreviations as in Tables 1 through 5.
41.7
1.89 (1.0–3.5) 13.4 (10.1–32.2)
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Table 7 Multivariable ANOVA results for hospital length-of-stay models Patient type
F
r2
Sex*
Facility type
Operative management
Multitrauma status
Presence of head injury
ISS
Pediatric Adult
17.323† 15.899†
0.414 0.255
0.021 (0.075) 0.008 (0.136)
0.136 (0.001) 0.056 (0.001)
0.001 (0.778) 0.039 (0.001)
0.021 (0.076) 0.017 (0.027)
0.059 (0.003) 0.045 (0.001)
0.183 (0.001) 0.025 (0.008)
* Independent variables are presented as partial eta2 (P value). † ⱕ0.001 ANOVA ⫽ analysis of variance; ISS ⫽ Injury Severity Score.
but costly hospital stays for these severely injured patients (Table 6). All adults who died were multitrauma patients, and the majority had sustained severe head injuries. As with our pediatric patients, we chose to exclude them from the multivariable ANOVA modeling. Table 7 lists the ANOVA model results for length of stay. Length of stay for both children and adults was associated with facility type when other patient and facility factors included in the model were controlled (P ⱕ0.001 for both). Head injury and admission ISS also demonstrated independent associations with length of stay for children. Our pediatric ANOVA model accounted for 41% of the variance overall. Operative management of splenic injury, multitrauma status, head injury, and ISS were independently associated with length of stay for adults. Multicollinearity between the independent variables included in the models was minimal. The overall r2 of the adult length-of-stay model was 0.25. Table 8 lists the multivariate ANOVA results for total charges. Facility type remained independently associated with total charges for both children and adults (P ⱕ0.001 for both). In addition, operative management of splenic injury, presence of head injury, and ISS showed statistically significant associations with total charges for both children and adults. The complete pediatric model was statistically significant and had an r2 of 0.49. Adult total charges were also associated with multitrauma status when all other included patient and facility factors were controlled. The r2 for this model was 0.40.
Comments The rate of nonoperative management of splenic injury in adults failed to match that of pediatric patients, likely for
physiologic as well as anatomic reasons [6,17]. Our results substantiated persistent differences in the management of splenic injury of adults and children. The demonstrated association between facility type and resource utilization for patients with traumatic splenic injury is novel and provides an important basis for the future study of resource utilization in trauma care. Nearly all previous studies found that children with splenic injury received different management at pediatric trauma centers than at regional hospitals, with pediatric centers displaying a higher rate of splenic preservation [4,7]. Our analysis reconfirms that children are more likely to undergo nonoperative management of splenic injury at a regional referral center than at an adult facility regardless of the adult facility’s trauma designation. Adult trauma patients with splenic injury included in previous studies were more likely to undergo operative management at a trauma than a nontrauma center [6,20,21]. Our results also showed that management of adult patients at level-I facilities is associated with increased rates of nonoperative management of splenic injury. Explanations posited for the higher rates of nonoperative management at level-I trauma centers include increased experience in trauma care, greater institutional commitment to trauma care, and better monitoring capabilities. Immediate availability of house staff for evaluation and care of patients may also enhance the rate of nonoperative management at teaching facilities. The primary justification for the development of trauma systems and centers has been improvement in clinical outcomes. Resource utilization in trauma care has been an area of burgeoning interest, particularly following the closure of a number of hospitals to trauma care in the 1980s and 1990s. In an environment of limited resources for trauma care,
Table 8 Multivariable ANOVA results for hospital total charge models Patient type
F
r2
Sex*
Facility type
Operative management
Multitrauma status
Presence of head injury
ISS
Pediatric Adult
23.824† 30.467†
0.493 0.396
0.073 (0.100) 0.000 (0.933)
0.073 (0.001) 0.150 (0.001)
0.036 (0.020) 0.094 (0.001)
0.000 (0.955) 0.042 (0.001)
0.090 (0.001) 0.055 (0.001)
0.183 (0.001) 0.030 (0.003)
* Independent variables are presented as partial eta2 (P value). † ⱕ0.001. ANOVA ⫽ analysis of variance; ISS ⫽ Injury Severity Score.
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improved cost-efficiency in trauma care is of paramount importance [22,23]. Although implementation and maintenance of trauma systems are costly activities, previous research has shown that trauma events treated within established systems of trauma care are 5% to 13% less costly per episode than events treated outside of established systems [24]. In contrast, our study demonstrated increased charges at designated trauma centers for the management of blunt splenic injury. The increased charges and prolonged lengths of stay at trauma centers in our study are proxies for increased resource utilization at these facilities in the care of the trauma patient. Care at trauma centers may be more costly because the presence of full-time specialist coverage and high-level technical support, both of which are necessary for care of the most severely injured patients [22]. Furthermore, the “average” trauma patient at a trauma center tends to be sicker and incur a longer hospitalization than patients at other facilities [25]. Pediatric patients treated at the pediatric referral facility or level-I trauma centers in our analysis were more severely injured as measured by ISS. In adults, the ISS of patients treated at level-I facilities and other facilities did not differ significantly. However, ISS may not adequately capture closed-head injury [26]. Facility type was consistently significant in our ANOVA modeling of length of stay and total charges for both pediatric and adult splenic injury patients. These differences in length of stay and total charges persisted even when the effects of ISS and head injury were controlled. Thus, injury severity and complexity may not provide a complete explanation of the increased resource utilization found at the pediatric referral center and the level-I trauma centers. Variation in management strategy played a significant but minor role in both length of stay and total charges incurred by trauma patients with splenic injury. Clancy et al [16] found no significant difference in length of stay or total charges between patients with splenic injury managed nonoperatively versus those managed surgically. Length of stay in our study tended to be longer for adults and children who underwent surgery for management of their splenic injury; total charges were also higher for those patients who were managed operatively, although this difference was only significant in adults. The independent effects of operative management on resource utilization demonstrated in our model may be confounded by other factors we have not successfully identified. One possible, although less palatable explanation for greater resource utilization at the level-I facilities may lie in their role as trauma teaching facilities. Inefficiencies in care provided in the teaching setting are assumed and are the bases for indirect medical education payments [27,28]. This inherent inefficiency has been ascribed to additional tests and procedures ordered by residents and reduced decreased productivity of hospital personnel who work with residents. Furthermore, patient cases at teaching facilities are often more complicated and require higher acuity of care than
patients treated at other facilities [29]. Available research addresses the indirect costs of graduate medical education in primary care and internal medicine; to the best of our knowledge, the indirect costs of resident training have not been evaluated specifically for surgery or trauma. One study comparing total costs per case in teaching and nonteaching hospitals demonstrated a 22.5% increase in actual costs at teaching hospitals over nonteaching, urban community hospitals [29]. The difference in total costs between nonteaching, urban community hospitals and academic medical centers in this same study was 82.9% [29]. In our study, total charges at the pediatric referral facility were 3 times those at other facilities, and charges for both adult and children were doubled at the level-I trauma centers compared with the other facilities. Although education may play a role in the increased use of resources at the level-I trauma centers, it was unlikely to be responsible for the entire difference. This study had several limitations. The retrospective use of administrative databases confined the data items that were available for analysis. Information unavailable from the databases included grading of splenic injury, use of management protocols, or specifics regarding operative management techniques. Several types of outcome data— including return to work or school, incidence of rehospitalization for complications, or short- and long-term quality of life after injury—might have been more robust than charge data. Any or all of these items would have supported a more rich analysis, but they also would have required access to medical records at each facility. The predictive ability of our multivariable models may also have been constrained by the absence of the previously described factors as independent variables. Data entry and coding are fraught with problems and may have influenced the adequacy of the data in the selected databases. ISS is sometimes not an adequate measure of injury severity and is particularly unreliable for patients with multiple, severe injuries within 1 region or in patients with head injury [26,30]. We addressed this consideration by using region-specific AIS scores and reviewing patient ICD-9 CM codes to establish both head injury and multitrauma status. Another limitation of our study was the reliability and completeness of the ICD-9 CM codes for diseases and procedures included in the databases. Erroneous entry of a splenic injury code would have resulted in inappropriate inclusion of a patient, whereas exclusion of a splenic injury diagnosis code from the available fields would have resulted in inappropriate exclusion of a patient. Our ability to determine the role of the splenic injury and its subsequent management on patient death was also dependent on accurate and complete entry of diagnostic codes from the death certificate. Although all early deaths were putatively attributable to head injury, we were unable to identify whether secondary physiologic effects resulting from nonoperative management may have played a role. Perhaps the key limitation of our analysis is its provision of a snapshot for a 2-year period that may no longer be
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representative of management patterns, length of stay, or charges for the included facilities. The prolonged time to availability of statewide databases is an unavoidable administrative issue, but it certainly provides a foundation for future analysis conducted in a similar manner to verify the consistency of these results over time. This study provides the groundwork for several avenues of future research. Confirmation of our results by similar studies in other states with nascent trauma systems would be of benefit. Study of other traumatic injuries comparing resource utilization by facility type would also clarify the generalizability of our findings. Finally, a broader study of the true costs of trauma care, particularly as these relate to education, would provide a significant contribution to the literature.
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[11] Cales RH, Trunkey DD. Preventable trauma deaths: a review of trauma care systems development. JAMA 1985;254:1059 – 63. [12] Champion HR, Sacco WJ, Copes WS. Improvement in outcome from trauma center care. Arch Surg 1992;127:333– 8. [13] Mann NC, Mullins RJ, MacKenzie EJ, et al. A systematic review of published evidence regarding trauma system effectiveness. J Trauma 1999;47(suppl):S25–33. [14] West J, Cales RH, Gazzinga A. Impact of regionalization: the Orange County experience. Arch Surg 1983;118:740 – 4. [15] Shackford S, Machersie R, Hoyt D. Impact of a trauma system on outcome of severely injured patients. Arch Surg 1987;122:523–7. [16] Clancy TV, Weintritt DC, Ramshaw DG, et al. Splenic salvage in adults at a level II community hospital trauma center. Am Surg 1996;62:1045–9. [17] Powell M, Courcoulas A, Gardner M, et al. Management of blunt splenic trauma: significant differences between adults and children. Surgery 1997;122:654 – 60. [18] Utah Governor’s Office of Planning and Budget. State of Utah Economic and Demographic Data, 2002. Available at: http://www. governor.utah.gov/dea/ERG2002.html. Accessed May 2004. [19] Jaro MA. Advances in record linkage methodology as applied to matching the 1985 census of Tampa, Florida. J Am Stat Assoc 1989;84:414 –9. [20] Rutledge R, Hunt JP, Lentz CW, et al. A statewide, population-based time-series analysis of the increasing frequency of nonoperative management of abdominal solid organ injury. Ann Surg 1995;222:311– 26. [21] Clancy TV, Ramshaw DG, Maxwell JG, et al. Management outcomes in splenic injury: a statewide trauma center review. Ann Surg 1997; 226:17–24. [22] Elliott DC, Rodriguez A. Cost effectiveness in trauma care. Surg Clin North Am 1996;6:47– 62. [23] Jacobs LM. Economic effects of managed care. Surg Clin North Am 1999;79:1249 –57. [24] Miller TR, Levy DT. Effect of regional trauma care systems on cost. Arch Surg 1990;30:188 –93. [25] Schwab CW, Young G, Civil I, et al. DRG reimbursement for trauma: the demise of the trauma center (the use of ISS grouping as an early predictor of total hospital cost). J Trauma 1988;28:939 – 46. [26] Valadka A. Injury to the cranium. In: Mattox KL, Feliciano DV, Moore EE, editors. Trauma. 4th ed. New York, NY: McGraw Hill; 2000:383. [27] Nasca TJ, Veloski JJ, Monnier JA, et al. Minimum instructional and program-specific administrative costs of educating residents in internal medicine. Arch Intern Med 2001;161:760 – 6. [28] Hogan AJ, Franzini L, Boex JR. Estimating the cost of primary care training in ambulatory settings. Health Econ 2000;9:715–26. [29] Mechanic R, Coleman K Dobson A. Teaching hospital costs: implications for academic mission in a competitive market. JAMA 1998; 280:1015–9. [30] Van Natta TL, Morris JA Jr. Injury scoring and trauma outcomes. In: Mattox KL, Feliciano DV, Moore EE, editors. Trauma. 4th ed. New York, NY: McGraw Hill; 2000:71, 73.
Scientific paper
Resource utilization and its management in splenic trauma Amalia Cochran, M.D., M.A.a,b, N. Clay Mann, Ph.D., M.S.b, J. Michael Dean, M.D., M.B.A.b, Lawrence J. Cook, M.Stat.b, Richard G. Barton, M.D.a,* a
Department of Surgery, School of Medicine, University of Utah, 30 N. 1900 East, Room 3B110, Salt Lake City, UT 84312, USA b Intermountain Injury Control Research Center, Salt Lake City, UT, USA Manuscript received April 22, 2003; revised manuscript October 18, 2003
Abstract Background: This study compared resource utilization and its management for splenic injury at 2 level-I trauma centers and a pediatric referral center with other facilities in a state currently developing a trauma system. Methods: Management strategy, length of stay, and total charges for children were compared among the pediatric referral center, trauma centers, and other facilities. Adult management, length of stay, and total charges were compared between trauma centers and other facilities. Results: Nonoperative management was more frequent in children at the pediatric referral center than trauma centers or other facilities and was more common in adults at trauma centers than at other facilities. Mean length of stay and total charges for children were significantly greater at the pediatric referral center and trauma centers than at other facilities and for adults at trauma centers than at other facilities. Facility type was associated with length of stay and total charges when injury type and severity were controlled. Conclusions: Nonoperative management of splenic injury is more common at trauma centers, and splenic trauma management may be more costly at trauma centers. © 2004 Excerpta Medica, Inc. All rights reserved. Keywords: Probabilistic data linkage; Resource utilization; Splenic trauma
The spleen is the most commonly injured organ in patients sustaining blunt abdominal trauma [1]. Because of a perception of increased mortality with nonoperative management, splenic injury historically has been managed operatively. Research in the early to mid-20th century demonstrated a variety of immunologic functions of the spleen; this research provided the foundation for a clinical paradigm shift toward splenic preservation after traumatic injury. Pediatric surgeons initiated nonoperative management of splenic injury because children are at higher risk of overwhelming postsplenectomy sepsis than adults [2]. The successful pediatric experience with nonoperative management of splenic injury has been extended to the management of adult trauma patients. The application of nonoperative management has broadened significantly as trauma surgeons have recognized that most splenic injuries can be managed nonoperatively. This management trend is well documented in the trauma literature, which shows a consis-
tent increase in the rate of nonoperative management of splenic injury [3– 6]. The preponderance of studies demonstrates that blunt splenic injury in children is more likely to be managed nonoperatively at a dedicated pediatric facility than at other facilities [4,7,8]. However, 1 recent study showed that dedicated trauma surgeons can obtain a rate of nonoperative management similar to their pediatric surgical colleagues in the care of children with splenic injury [9]. Differences also exist between rural and urban facilities in the management of adults with splenic injuries [8]. In this study, we reviewed the management patterns of blunt splenic injury in a single state. Specifically, we compared the management of splenic injury at Utah’s 2 statedesignated level-I trauma centers and a regional pediatric referral facility with management at all other hospitals in Utah.
Resource utilization in splenic injury * Corresponding author. Tel.: ⫹1-801-581-4314; fax: ⫹1-801-5879149. E-mail address: [email protected]
Trauma centers and trauma systems clearly show improved clinical outcomes in critically injured trauma pa-
0002-9610/04/$ – see front matter © 2004 Excerpta Medica, Inc. All rights reserved. doi:10.1016/j.amjsurg.2003.10.021
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tients [10 –15]. However, the impact of trauma centers on the costs of trauma care remains unclear. The current political and economic milieu of health care demands that patients receive the best care available at the lowest cost. Resource utilization provides an important but seldom used means for evaluating cost-efficiency in trauma care. We identified only 1 published study examining resource utilization in the management of splenic injury [16]. Clancy et al [16] compared the impact of operative versus nonoperative management of splenic injury on length of stay and average hospital charges for adult patients at a single level-II trauma center. We are unaware of any study of resource utilization for splenic injury comparing level-I trauma centers with nondesignated facilities. Our study compared resource utilization in the management of splenic injury at state-designated level-I trauma centers, a regional pediatric referral facility, and all other hospitals in the state of Utah. Length of stay and total charges served as measures of resource utilization.
Methods Study design This study was a retrospective cohort analysis of resource utilization among patients with blunt splenic trauma managed at two level-I trauma centers or a regional pediatric referral center compared with other hospitals. We evaluated pediatric and adult patients separately because the rate of nonoperative management of splenic injury is generally much higher for children [6,17]. We compared management strategy, length of stay, and total charges for children with splenic injury between the regional pediatric referral center, the two level-I trauma centers, and all other hospitals. We also compared the level-I trauma centers with all other community-level hospitals using the same dependent variables for adults. Study population and data sources Utah is a largely rural state with 75% of the population concentrated in a 4-county area known as the Wasatch Front [18]. The Wasatch Front runs approximately 90 miles along the western edge of the Wasatch Mountains, extending from Ogden in the north to Provo in the south. Both of the state-designated level-I facilities and the pediatric referral facility are located in this area. Aside from these 3 facilities, no other hospitals in Utah are verified as trauma centers by the American College of Surgeons. The Utah emergency department (ED), hospital discharge, and death certificate databases for 1996 and 1997 were used in this analysis. The ED and hospital discharge databases were obtained from the Utah Health Data Committee/Office of Health Data Analysis. Appropriate data must be reported to these databases under state law. These
databases include demographic information, International Classification of Diseases-9 Clinical Modification (ICD-9 CM) codes, E-codes, billing information, and hospital charges. The Utah ED database includes patients who present to the ED and who are subsequently are discharged to home or who are transferred to another health care facility for inpatient care. Patients seen in the ED and subsequently admitted to the same facility are included only in the Utah hospital discharge database. We included only inpatient admissions in our analysis. The Utah death certificate database was obtained from the Bureau of Vital Statistics through the University of Utah Resource for Genetic and Epidemiologic Research. This database includes demographic information, up to 4 ICD-9 CM codes, and E-codes as appropriate. We included data from the vital statistics database for identification of 30-day mortality after hospital discharge. The University of Utah Institutional Review Board approved the use of these databases for the purposes of this study. Probabilistic linkage Probabilistic linkage is a technique that uses probability to link records from multiple data sources that apply to the same person or event. This methodology links records among ⱖ2 data sets through calculation of probability weights including adjustments for incomplete or missing data. Jaro [19] previously described computerized probabilistic linkage in some detail. CODES 2000 (Strategic Matching, Inc., Morrisonville, New York) was used to perform probabilistic linkage employing an iterative approach that mathematically links databases not originally designed for linkage. Probabilistic linkage of the ED, hospital discharge, and death certificate databases generated the data set used for statistical analysis. Probabilistic record linkage is accomplished by comparing data fields such as birth date or sex in 2 files. Comparison of numerous data fields leads to a judgment that 2 records refer to the same patient and should be linked. This judgment is based on the cumulative weight of agreement and disagreement among field values. The amount of information contained in a field is related to that field’s impact on the judgment process. For instance, agreement of the sex field alone would not provide sufficient weight to determine that 2 records refer to the same patient, but agreement on Social Security Number nearly guarantees that 2 records refer to the same patient. We performed a 1-to-1 linkage, meaning an individual ED record or death record was allowed to link to only 1 hospital discharge record. Variables included were date of hospital visit, patient date of birth, hospital code, county code, city code, sex, and age. The software cleared patients who were admitted to one hospital then transferred to another. Once we created the database linkage file, we limited the data set based on ICD-9 CM codes from the hospital
A. Cochran et al. / The American Journal of Surgery 187 (2004) 713–719
discharge database that were specific to internal injury to the spleen (865.0 to 865.1 with any fifth digit).
Table 1 Patient characteristics Characteristic
Pediatric patients (n ⫽ 159)
Adult patients (n ⫽ 305)
Sex (% male) Mean ⫾ SD age (years) Mean ⫾ SD ISS Multitrauma (%) Head injury (%) Rate of nonoperative management (%) Deaths (%)
66.0 12.3 ⫾ 4.2 16.1 ⫾ 12.4 45.3 20.7 80.5
64.9 35.9 ⫾ 17.4 21.8 ⫾ 12.7 74.7 14.4 54.1
Data definitions Several variables were generated from the data included in the linked file. ICDMAP-90 software (Johns Hopkins University and Tri-Analytics, Inc., Baltimore, Maryland) was used to calculate abbreviated injury scores (AIS) and the Injury Severity Score (ISS) for all patients included in the analysis. Nonoperative management was defined as the absence of the following ICD-9 CM procedure codes from a patient’s medical record: 41.4 (excision or destruction of lesion or tissue of spleen); 41.5 (total splenectomy); 41.95 (repair or plastic operations on the spleen); and 41.99 (other operations on the spleen). The hospital identification number was used to identify facility type as pediatric referral center, level-I trauma center, or other nondesignated facility. Multitrauma status was defined as any patient with ICD-9 CM codes inconsistent with the presence of isolated abdominal injury. Clinically significant head injury was defined as any patient with a head region AIS ⱖ3. Length of stay and total charges demonstrated nonnormal distributions and were therefore log-transformed for modeling purposes. Statistical analysis We designated patients ⬍18 years old as children for analysis purposes. The Student t test was used to compare the mean age and ISS of children treated at the pediatric referral center with those treated at the level-I trauma centers and all other facilities. Chi-square analyses compared the proportion of male patients, frequency of head injury, presence of isolated abdominal trauma, and the type of management strategy between children managed at the pediatric referral center, those treated at level-I facilities, and those treated elsewhere. The Kruskal-Wallis test was used to analyze the differences in median length of stay and hospital charges between the pediatric referral center, level-I centers, and all other facilities for children who sustained splenic trauma. Data for adult patients were analyzed using the Wilcoxon Rank Sum test comparing level-I trauma centers with all other hospitals. Log-transformed length of stay and total charges were employed as the dependent variables in analysis of variance (ANOVA) models that controlled for patient demographics, injury type, and injury severity. We created separate multivariable ANOVA models for children and adults.
Results One hundred fifty-nine children and 305 adults underwent inpatient management of splenic injury in the state of Utah during 1996 and 1997 (Table 1). The rate of nonoperative management of splenic injury was 81% for children
715
3.1
3.9
ISS ⫽ Injury Severity Score.
and 54% for adults. A greater proportion of adult patients were multitrauma patients, but relatively more children suffered head injuries. Twenty percent of adults sustained a pelvic fracture. Other common injuries in adults included spine fractures (14% of patients) and femur fractures (5% of patients). The mortality rates for patients with traumatic splenic injury were 3% for children and 4% for adults. Pediatric patients Children with splenic injury managed at the pediatric referral center showed several key differences from children managed at level-I facilities or other nondesignated hospitals (Table 2). Children treated at the pediatric referral facility were significantly younger than children treated at either level-I trauma centers or other facilities (P ⱕ0.001). Mean injury severity score of children treated at the pediatric referral center or the level-I trauma centers was significantly higher than that of children managed at other hospitals (P ⬍0.018). Children with head injury in conjunction with their splenic injury were significantly more likely to be treated at the pediatric referral center or the level-I trauma centers (P ⱕ0.001). The incidence of isolated abdominal injury was significantly lower at the pediatric referral center and the level-I trauma centers than at other facilities. Table 2 Pediatric demographic data: pediatric referral center versus level-I trauma centers versus all other facilities Demographic data
Mean ⫾ SD age (years) Sex (% male) Mean ⫾ SD ISS Head injury (%) Isolated abdominal trauma (%)
Pediatric referral center (n ⫽ 48)
Level-I trauma centers (n ⫽ 27)
All other (n ⫽ 84)
P value
9.0 ⫾ 4.4
15.4 ⫾ 2.4
13.1 ⫾ 3.4
ⱕ0.001
64.6 18.1 ⫾ 14.5 22.9 37.5
55.6 20.3 ⫾ 11.1 18.5 37.0
71.4 13.5 ⫾ 11.0 2.4 70.2
0.300 0.018 ⱕ0.001 ⱕ0.001
ISS ⫽ Injury Severity Score.
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Table 3 Pediatric management and resource utilization: pediatric referral center versus level-I trauma centers versus all other facilities
Table 5 Adult management and resource utilization: level I versus nontrauma centers
Management and Pediatric utilization referral center (n ⫽ 48)
Management and utilization
Level I trauma centers (n ⫽ 134)
All other facilities (n ⫽ 171)
Nonoperative management (%) Median LOS days (IQR) Median total charges $1000 (IQR)
61.2
48.5
Level-I trauma centers (n ⫽ 27)
All other (n ⫽ 84)
P value
Nonoperative 93.7 70.4 76.2 0.009 management (%) Median LOS days 5.0 (3.3–10) 5.0 (4.0–9.0) 4.0 (2.0–5.0) ⱕ0.001 (IQR) Median total 11.1 (5.4–23.1) 12.1 (6.5–43.3) 6.7 (4.5–9.9) ⱕ0.001 charges $1000 (IQR) IQR ⫽ interquartile range; LOS ⫽ length of stay.
Children treated at the pediatric referral center were significantly more likely to undergo nonoperative management of their splenic injury than were children treated at the level-I centers or other hospitals (94% vs. 70% vs. 76%, respectively; Table 3). The results demonstrated a longer median length of stay for patients managed at the pediatric referral center and the level-I trauma centers than for the children managed elsewhere (5 days vs. 5 days vs. 4 days, respectively; P ⱕ0.001). Significantly higher median total charges were also incurred at the pediatric referral facility and the level-I trauma centers than at other facilities in the management of pediatric trauma patients with splenic injury ($11,129 vs. $12,070 vs. $6,679, respectively; P ⱕ0.001). Adult patients Mean age, mean ISS, and gender distribution did not differ significantly between adult splenic injury patients treated at level-I trauma centers and those treated elsewhere (Table 4). The prevalence of head injury in conjunction with splenic injury was doubled in patients treated at level-I trauma centers versus those managed at nondesignated facilities. Only 13% of the patients treated for splenic injury at level-I trauma centers had isolated abdominal injuries versus 34% of the patients treated at other hospitals. Table 4 Adult demographic data: level-I versus nontrauma centers Demographic data
Level-I trauma centers (n ⫽ 134)
All other facilities (n ⫽ 171)
P value
Mean ⫾ SD age (years) Sex (% male) Mean ⫾ SD ISS Head injury (%) Isolated abdominal trauma (%)
37.0 ⫾ 16.8 63.4 22.6 ⫾ 12.5 20.0 13.4
35.0 ⫾ 17.8 66.7 21.3 ⫾ 12.9 10.6 34.5
0.330 0.556 0.357 0.024 ⱕ0.001
ISS ⫽ Injury Severity Score.
8.0 (5–12.2) 25.6 (14.4–49.8)
P value
0.027
6.0 (4.0–8.0)
ⱕ0.001
11.3 (7.7–20.1)
ⱕ0.001
Abbreviations as in Table 3.
Adults with splenic injury who received care at level-I trauma centers were more likely to undergo nonoperative management (61% vs. 48%, P ⫽ 0.027; Table 5). Median length of stay was 8 days at the level-I trauma centers and 6 days at other hospitals (P ⱕ0.001). Median total charges at the level-I centers were more than twice the charges at nondesignated facilities ($25,606 vs. $11,345; P ⱕ0.001). Multivariable analysis–resource utilization All of the children who died were treated at the pediatric referral center, resulting in a potential effect of these 5 children on statistical modeling of resource utilization (Table 6). Three of these children died during a 1-day length of stay, and 1 died during a 2-day length of stay. Perhaps most importantly, they all died as a result of traumatic brain injury. The paucity of these deaths makes it difficult to adequately model the impact of mortality, and we therefore excluded from subsequent analyses those children who died. Our concerns about the impact of mortality on modeling of resource utilization in children were also present for adults. We noted that 8 of the adults who died did so during the first 24 hours of their hospitalization, resulting in brief Table 6 Demographic and injury characteristics of deaths Characteristic
Children (n ⫽ 5)
Adults (n ⫽ 12)
Mean ⫾ SD age (years) Sex (% male) Mean ⫾ SD ISS Head injury (%) Multitrauma (%) Operative management of splenic injury (%) Management at pediatric referral center or level-I center (%) Median LOS days (IQR) Median total charges $1000 (IQR)
6.8 ⫾ 3.3 68 48.6 ⫾ 12.3 100 100 40.0
47.1 ⫾ 24.6 80 45.1 ⫾ 15.0 67.0 100 50.0
100
1.5 (1.0–4.5) 23.4 (16.6–41.9)
Abbreviations as in Tables 1 through 5.
41.7
1.89 (1.0–3.5) 13.4 (10.1–32.2)
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Table 7 Multivariable ANOVA results for hospital length-of-stay models Patient type
F
r2
Sex*
Facility type
Operative management
Multitrauma status
Presence of head injury
ISS
Pediatric Adult
17.323† 15.899†
0.414 0.255
0.021 (0.075) 0.008 (0.136)
0.136 (0.001) 0.056 (0.001)
0.001 (0.778) 0.039 (0.001)
0.021 (0.076) 0.017 (0.027)
0.059 (0.003) 0.045 (0.001)
0.183 (0.001) 0.025 (0.008)
* Independent variables are presented as partial eta2 (P value). † ⱕ0.001 ANOVA ⫽ analysis of variance; ISS ⫽ Injury Severity Score.
but costly hospital stays for these severely injured patients (Table 6). All adults who died were multitrauma patients, and the majority had sustained severe head injuries. As with our pediatric patients, we chose to exclude them from the multivariable ANOVA modeling. Table 7 lists the ANOVA model results for length of stay. Length of stay for both children and adults was associated with facility type when other patient and facility factors included in the model were controlled (P ⱕ0.001 for both). Head injury and admission ISS also demonstrated independent associations with length of stay for children. Our pediatric ANOVA model accounted for 41% of the variance overall. Operative management of splenic injury, multitrauma status, head injury, and ISS were independently associated with length of stay for adults. Multicollinearity between the independent variables included in the models was minimal. The overall r2 of the adult length-of-stay model was 0.25. Table 8 lists the multivariate ANOVA results for total charges. Facility type remained independently associated with total charges for both children and adults (P ⱕ0.001 for both). In addition, operative management of splenic injury, presence of head injury, and ISS showed statistically significant associations with total charges for both children and adults. The complete pediatric model was statistically significant and had an r2 of 0.49. Adult total charges were also associated with multitrauma status when all other included patient and facility factors were controlled. The r2 for this model was 0.40.
Comments The rate of nonoperative management of splenic injury in adults failed to match that of pediatric patients, likely for
physiologic as well as anatomic reasons [6,17]. Our results substantiated persistent differences in the management of splenic injury of adults and children. The demonstrated association between facility type and resource utilization for patients with traumatic splenic injury is novel and provides an important basis for the future study of resource utilization in trauma care. Nearly all previous studies found that children with splenic injury received different management at pediatric trauma centers than at regional hospitals, with pediatric centers displaying a higher rate of splenic preservation [4,7]. Our analysis reconfirms that children are more likely to undergo nonoperative management of splenic injury at a regional referral center than at an adult facility regardless of the adult facility’s trauma designation. Adult trauma patients with splenic injury included in previous studies were more likely to undergo operative management at a trauma than a nontrauma center [6,20,21]. Our results also showed that management of adult patients at level-I facilities is associated with increased rates of nonoperative management of splenic injury. Explanations posited for the higher rates of nonoperative management at level-I trauma centers include increased experience in trauma care, greater institutional commitment to trauma care, and better monitoring capabilities. Immediate availability of house staff for evaluation and care of patients may also enhance the rate of nonoperative management at teaching facilities. The primary justification for the development of trauma systems and centers has been improvement in clinical outcomes. Resource utilization in trauma care has been an area of burgeoning interest, particularly following the closure of a number of hospitals to trauma care in the 1980s and 1990s. In an environment of limited resources for trauma care,
Table 8 Multivariable ANOVA results for hospital total charge models Patient type
F
r2
Sex*
Facility type
Operative management
Multitrauma status
Presence of head injury
ISS
Pediatric Adult
23.824† 30.467†
0.493 0.396
0.073 (0.100) 0.000 (0.933)
0.073 (0.001) 0.150 (0.001)
0.036 (0.020) 0.094 (0.001)
0.000 (0.955) 0.042 (0.001)
0.090 (0.001) 0.055 (0.001)
0.183 (0.001) 0.030 (0.003)
* Independent variables are presented as partial eta2 (P value). † ⱕ0.001. ANOVA ⫽ analysis of variance; ISS ⫽ Injury Severity Score.
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improved cost-efficiency in trauma care is of paramount importance [22,23]. Although implementation and maintenance of trauma systems are costly activities, previous research has shown that trauma events treated within established systems of trauma care are 5% to 13% less costly per episode than events treated outside of established systems [24]. In contrast, our study demonstrated increased charges at designated trauma centers for the management of blunt splenic injury. The increased charges and prolonged lengths of stay at trauma centers in our study are proxies for increased resource utilization at these facilities in the care of the trauma patient. Care at trauma centers may be more costly because the presence of full-time specialist coverage and high-level technical support, both of which are necessary for care of the most severely injured patients [22]. Furthermore, the “average” trauma patient at a trauma center tends to be sicker and incur a longer hospitalization than patients at other facilities [25]. Pediatric patients treated at the pediatric referral facility or level-I trauma centers in our analysis were more severely injured as measured by ISS. In adults, the ISS of patients treated at level-I facilities and other facilities did not differ significantly. However, ISS may not adequately capture closed-head injury [26]. Facility type was consistently significant in our ANOVA modeling of length of stay and total charges for both pediatric and adult splenic injury patients. These differences in length of stay and total charges persisted even when the effects of ISS and head injury were controlled. Thus, injury severity and complexity may not provide a complete explanation of the increased resource utilization found at the pediatric referral center and the level-I trauma centers. Variation in management strategy played a significant but minor role in both length of stay and total charges incurred by trauma patients with splenic injury. Clancy et al [16] found no significant difference in length of stay or total charges between patients with splenic injury managed nonoperatively versus those managed surgically. Length of stay in our study tended to be longer for adults and children who underwent surgery for management of their splenic injury; total charges were also higher for those patients who were managed operatively, although this difference was only significant in adults. The independent effects of operative management on resource utilization demonstrated in our model may be confounded by other factors we have not successfully identified. One possible, although less palatable explanation for greater resource utilization at the level-I facilities may lie in their role as trauma teaching facilities. Inefficiencies in care provided in the teaching setting are assumed and are the bases for indirect medical education payments [27,28]. This inherent inefficiency has been ascribed to additional tests and procedures ordered by residents and reduced decreased productivity of hospital personnel who work with residents. Furthermore, patient cases at teaching facilities are often more complicated and require higher acuity of care than
patients treated at other facilities [29]. Available research addresses the indirect costs of graduate medical education in primary care and internal medicine; to the best of our knowledge, the indirect costs of resident training have not been evaluated specifically for surgery or trauma. One study comparing total costs per case in teaching and nonteaching hospitals demonstrated a 22.5% increase in actual costs at teaching hospitals over nonteaching, urban community hospitals [29]. The difference in total costs between nonteaching, urban community hospitals and academic medical centers in this same study was 82.9% [29]. In our study, total charges at the pediatric referral facility were 3 times those at other facilities, and charges for both adult and children were doubled at the level-I trauma centers compared with the other facilities. Although education may play a role in the increased use of resources at the level-I trauma centers, it was unlikely to be responsible for the entire difference. This study had several limitations. The retrospective use of administrative databases confined the data items that were available for analysis. Information unavailable from the databases included grading of splenic injury, use of management protocols, or specifics regarding operative management techniques. Several types of outcome data— including return to work or school, incidence of rehospitalization for complications, or short- and long-term quality of life after injury—might have been more robust than charge data. Any or all of these items would have supported a more rich analysis, but they also would have required access to medical records at each facility. The predictive ability of our multivariable models may also have been constrained by the absence of the previously described factors as independent variables. Data entry and coding are fraught with problems and may have influenced the adequacy of the data in the selected databases. ISS is sometimes not an adequate measure of injury severity and is particularly unreliable for patients with multiple, severe injuries within 1 region or in patients with head injury [26,30]. We addressed this consideration by using region-specific AIS scores and reviewing patient ICD-9 CM codes to establish both head injury and multitrauma status. Another limitation of our study was the reliability and completeness of the ICD-9 CM codes for diseases and procedures included in the databases. Erroneous entry of a splenic injury code would have resulted in inappropriate inclusion of a patient, whereas exclusion of a splenic injury diagnosis code from the available fields would have resulted in inappropriate exclusion of a patient. Our ability to determine the role of the splenic injury and its subsequent management on patient death was also dependent on accurate and complete entry of diagnostic codes from the death certificate. Although all early deaths were putatively attributable to head injury, we were unable to identify whether secondary physiologic effects resulting from nonoperative management may have played a role. Perhaps the key limitation of our analysis is its provision of a snapshot for a 2-year period that may no longer be
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representative of management patterns, length of stay, or charges for the included facilities. The prolonged time to availability of statewide databases is an unavoidable administrative issue, but it certainly provides a foundation for future analysis conducted in a similar manner to verify the consistency of these results over time. This study provides the groundwork for several avenues of future research. Confirmation of our results by similar studies in other states with nascent trauma systems would be of benefit. Study of other traumatic injuries comparing resource utilization by facility type would also clarify the generalizability of our findings. Finally, a broader study of the true costs of trauma care, particularly as these relate to education, would provide a significant contribution to the literature.
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