Is there a July phenomenon? The effect of July admission on intensive care mortality and length of stay in teaching hospitals

BACKGROUND: It has been suggested that inexperience of new housestaff early in an academic year may worsen patient outcomes. Yet, few studies have evaluated the "July Phenomenon," and no studies have investigated its effect in intensive care patients, a group that may be particularly susceptible to deficiencies in management stemming from housestaff inexperience. OBJECTIVE: Compare hospital mortality and length of stay (LOS) in intensive care unit (ICU) admissions from July to September to admissions during other months, and compare that relationship in teaching and nonteaching hospitals, and in surgical and nonsurgical patients. DESIGN, SETTING, AND PATIENTS: Retrospective cohort analysis of 156,136 consecutive eligible patients admitted to 38 ICUs in 28 hospitals in Northeast Ohio from 1991 to 1997. RESULTS: Adjusting for admission severity of illness using the APACHE III methodology, the odds of death was similar for admissions from July through September, relative to the mean for all months, in major (odds ratio [OR], 0.96; 95% confidence interval [95% CI], 0.91 to 1.02; P = .18), minor (OR, 1.02; 95% CI, 0.93 to 1.10; P = .66), and nonteaching hospitals (OR, 0.96; 95% CI, 0.91 to 1.01; P = .09). The adjusted difference in ICU LOS was similar for admissions from July through September in major (0.3%; 95% CI, -0.7% to 1.2%; P = .61) and minor (0.2%; 95% CI, -0.9% to 1.4%; P = .69) teaching hospitals, but was somewhat shorter in nonteaching hospitals (-0.8%; 95% CI, -1.4% to -0.1%; P = .03). Results were similar when individual months and academic years were examined separately, and in stratified analyses of surgical and nonsurgical patients. CONCLUSIONS: We found no evidence to support the existence of a July phenomenon in ICU patients. Future studies should examine organizational factors that allow hospitals and residency programs to compensate for inexperience of new housestaff early in the academic year.