Association Between Emergency Physician Length of Stay Rankings and Patient Characteristics

Objective Emergency physicians are commonly compared by their patients' length of stay (LOS). We test the hypothesis that LOS is associated with patient characteristics and that accounting for these features impacts physician LOS rankings. Methods This was a retrospective observational study of all encounters at an emergency department in 2010 to 2015. We compared the characteristics of patients seen by physicians in different quartiles of LOS. Primary outcome was variation in patient characteristics at time of physician assignment (age, sex, comorbidities, Emergency Severity Index [ESI], and chief complaint) across LOS quartiles. We also quantified the change in LOS rankings after accounting for difference in characteristics of patients seen by different physicians. Results A total of 264,776 encounters seen by 62 attending physicians met inclusion criteria. Physicians in the longest LOS quartile saw patients who were older (age = 49.1 vs 48.6 years, difference = +0.5 years, 95% confidence interval [CI] = 0.3 to 0.7) with more comorbidities (Gagne score = 1.3 vs. 0.9, difference = +0.4, 95% CI = 0.4 to 0.4) and higher acuity (ESI = 2.8 vs. 2.9, difference = -0.1, 95% CI = 0.1 to 0.1) than physicians in the shortest LOS quartile. The odds ratio (OR) of physicians in the longest LOS quartile seeing patients over age 50 compared to the shortest LOS quartile was 1.1 (95% CI = 1.0 to 1.1); the OR of physicians in the longest LOS quartile seeing patients with ESI of 1 or 2 was also 1.1 (95% CI = 1.0 to 1.1). Accounting for variation in patient characteristics seen by different physicians resulted in substantial reordering of physician LOS rankings: 62.9% (39/62) of physicians reclassified into a different quartile with mean absolute percentile change of 25.8 (95% CI = 20.3 to 31.3). A total of 62.5% (10/16) of physicians in the shortest LOS quartile and 56.3% (9/16) in the longest LOS quartile moved into a different quartile after accounting for variation in patient characteristics. Conclusions Length of stay was significantly associated with patient characteristics, and accounting for variation in patient characteristics resulted in substantial reordering of relative physician rankings by LOS. Comparisons of emergency physicians by LOS that do not account for patient characteristics should be reconsidered.