Validation of Length of Hospital Stay as a Surrogate Measure for Injury Severity and Resource Use Among Injury Survivors

Center for Policy and Research in Emergency Medicine, Department of Emergency Medicine, Oregon Health & Science University, Portland, OR, USA.
Academic Emergency Medicine (Impact Factor: 2.01). 02/2010; 17(2):142-50. DOI: 10.1111/j.1553-2712.2009.00647.x
Source: PubMed


While hospital length of stay (LOS) has been used as a surrogate injury outcome when more detailed outcomes are unavailable, it has not been validated. This project sought to validate LOS as a proxy measure of injury severity and resource use in heterogeneous injury populations.
This observational study used four retrospective cohorts: patients presenting to 339 California emergency departments (EDs) with a primary International Classification of Diseases, Ninth Revision (ICD-9), injury diagnosis (years 2005-2006); California hospital injury admissions (a subset of the ED population); trauma patients presenting to 48 Oregon EDs (years 1998-2003); and injured Medicare patients admitted to 171 Oregon and Washington hospitals (years 2001-2002). In-hospital deaths were excluded, as they represent adverse outcomes regardless of LOS. Duration of hospital stay was defined as the number of days from ED admission to hospital discharge. The primary composite outcome (dichotomous) was serious injury (Injury Severity Score [ISS] >or= 16 or ICD-9 ISS <or= 0.90) or resource use (major surgery, blood transfusion, or prolonged ventilation). The discriminatory accuracy of LOS for identifying the composite outcome was evaluated using receiver operating characteristic (ROC) analysis. Analyses were also stratified by age (0-14, 15-64, and >or=65 years), hospital type, and hospital annual admission volume.
The four cohorts included 3,989,409 California ED injury visits (including admissions), 236,639 California injury admissions, 23,817 Oregon trauma patients, and 30,804 Medicare injury admissions. Composite outcome rates for the four cohorts were 2.1%, 29%, 27%, and 22%, respectively. Areas under the ROC curves for overall LOS were 0.88 (California ED), 0.74 (California admissions), 0.82 (Oregon trauma patients), and 0.68 (Medicare patients). In general, the discriminatory value of LOS was highest among children, tertiary trauma centers, and higher volume hospitals, although this finding differed by the injury population and outcome assessed.
Hospital LOS may be a reasonable proxy for serious injury and resource use among injury survivors when more detailed outcomes are unavailable, although the discriminatory value differs by age and the injury population being studied.

Download full-text


Available from: Esther K Choo, Sep 04, 2014
18 Reads
  • Source
    • "Whiplash injury is included in the musculoskeletal injury group, but because this specific condition is common and antidepressants can be prescribed as treatment, whiplash injury was coded as a separate variable. Hospital stay in number of days was categorised as none, one day, and two or more days; hospital stay was considered a proxy for injury severity [13] [14]. And finally, claim delay was calculated as the number of days between the accident date and the date the claim was received by the TAC. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Mental ill health after road traffic injury is common, as is the use of antidepressant medication after injury. Little is known about antidepressant use by injured people prior to their injury. The aim of this study is to describe the nature and extent of antidepressant use before and after road traffic injury. Victorian residents who claimed Transport Accident Commission (TAC) compensation for a non-catastrophic injury that occurred between 2010 and 2012 and provided consent for Pharmaceutical Benefits Scheme (PBS) linkage were included (n=734). PBS records dating from 12 months prior through to 12 months post injury were provided by the Department of Human Services (Canberra). PBS and TAC claims data were linked. Among participants, 12% used antidepressants before injury (84.4Defined Daily Doses/1000person-days) and 17% used antidepressants after injury (114.1DDD/1000p-d). Only 7.7% of the injured cohort commenced antidepressant treatment post injury. Thus, of all post-injury antidepressant use, 45% could potentially be related to the incident injury, with the remaining 55% most probably a continuation of pre-injury use. Pre-injury use was more common among women (109.4 vs. 54.6DDD/1000p-d, p<0.0001), and those with whiplash injury (119.3 vs. 73.1, p=0.03). Cyclists and motorcyclists were less likely to use antidepressants pre-injury than car drivers (18.3 vs. 16.9 vs. 109.3, respectively; p<0.001). Less than half of post-injury antidepressant use could potentially be attributable to the incident injury. These results highlight the importance of obtaining information on pre-injury health status before interpreting post-injury health service use to be an outcome of the injury in question. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Injury 03/2015; 46(7). DOI:10.1016/j.injury.2015.02.023 · 2.14 Impact Factor
  • Source
    • "Previous paediatric injury research has used time spent in hospital as a measure for injury severity, with longer hospital stays indicating more acute injuries [39]. The use of length of stay as a surrogate measure has been validated in paediatric populations where the likelihood of medical fragility and co-morbidities are low [40]. To examine the relationship between HRQL and severity of injury, length of stay was stratified into three categories for the analyses: not admitted, admitted for one to three days, and admitted for four or more days. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Injuries are a leading cause of death and disabilities for children and youth globally. Measuring the health related quality of life of injured children and youth can help gain understanding of the impact of injuries on this population; however, psychometric evaluation of health related quality of life tools among this population is lacking. The purpose of this study was to determine the construct validity of the EQ-5D-3LTM for use among a population of injured young people and to examine the reliability of different modes of administration including paper and pencil, online and telephone. In total, 345 participants (aged 0 -- 16) were recruited from a paediatric hospital in a large urban centre in British Columbia, Canada. To capture a variety of injury types and severity, patients were recruited from in-patient units and the emergency department. Data were collected at the time of recruitment and at one month post injury. Repeated measures analysis (rANOVA) showed that EQ-5D-3LTM scores were different before and after injury and significant between group differences (Visual Analog Scale: F = 4.61, p = 0.011; Descriptive Scale: F = 29.58, p < 0.001), within group differences (Visual Analog Scale: F = 60.02, p < 0.001; Descriptive Scale: F = 92.37, p < 0.001), and interaction between variables (Visual Analog Scale: F = 10.89, p < 0.001; Descriptive Scale: F = 19.25, p < 0.001) were detected, indicating its suitability for assessment of post-injury health related quality of life. Bland-Altman plots confirmed that few differences existed between modes of administration. The EQ-5D-3LTM is an appropriate instrument for collecting health related quality of life data among injured children and can be administered via paper-pencil, online or by telephone.
    Health and Quality of Life Outcomes 09/2013; 11(1):157. DOI:10.1186/1477-7525-11-157 · 2.12 Impact Factor
  • Source
    • "Patients with more severe injuries are expected to stay in the hospital longer than patients with less severe injuries. Newgard et al. validated LOS as a proxy indicator for injury severity in trauma survivors [4]. Our findings do not corroborate with those of the Newgard et al. study. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Earthquakes are the most violent type of natural disasters and injuries are the dominant medical problem in the early phases after earthquakes. However, likely because of poor data availability, high-quality research on injuries after earthquakes is lacking. Length of hospital stay (LOS) has been validated as a proxy indicator for injury severity in high-income settings and could potentially be used in retrospective research of injuries after earthquakes. In this study, we assessed LOS as an adequate proxy indicator for severe injury in trauma survivors of an earthquake. A retrospective analysis was conducted using a database of 1,878 injured patients from the 2008 Wenchuan earthquake. Our primary outcome was severe injury, defined as a composite measure of serious injury or resource use. Secondary outcomes were serious injury and resource use, analysed separately. Non-parametric receiver operating characteristics (ROC) and area under the curve (AUC) analysis was used to test the discriminatory accuracy of LOS when used to identify severe injury. An 0.7<AUC<0.8 was defined as adequate. Our study shows that LOS discriminatory accuracy is poor for the primary outcome. However, LOS discriminatory accuracy is adequate for resource use, excluding critical orthopaedic interventions and debridement. Length of hospital stay was not validated as a proxy indicator for severe injury in earthquake survivors. However, LOS was found to be a proxy for major nonorthopaedic surgery and blood transfusion. These findings can be useful for retrospective research on earthquake-injured patients when detailed hospital records are not available.
    PLoS ONE 04/2013; 8(4):e61371. DOI:10.1371/journal.pone.0061371 · 3.23 Impact Factor
Show more