Effect of work-hours regulations on intensive care unit mortality in United States teaching hospitals

Abstract

Objectives: : To examine the association of the resident work-hours reform with mortality for patients in medical and surgical intensive care units. The United States instituted restrictions on resident work-hours in July 2003. The clinical impact of this reform on critically ill patients is unknown.

Design: : A retrospective cohort study, comparing mortality trends before and after July 1, 2003, in teaching and nonteaching hospitals.

Setting and patients: : The study included 230,151 adult patients admitted to 104 different intensive care units at 40 hospitals participating in the Acute Physiology and Chronic Health Evaluation IV clinical information system from July 1, 2001, to June 30, 2005.

Interventions: : None.

Measurements and main results: : The primary exposure was the date of admission, relative to the implementation of the work-hours regulations. The primary outcome was in-hospital mortality; a secondary outcome was intensive care unit mortality. The analysis included 79,377 patients in 12 academic hospitals; 73,580 patients in 12 community hospitals with residents; and 77,194 patients in 16 nonteaching hospitals. Risk-adjusted mortality improved in hospitals of all teaching levels during the study period. There were no significant differences in the mortality trends between hospitals of different teaching intensities, as demonstrated by nonsignificant interaction between time and teaching status (global test of interaction, p = .56).

Conclusions: : There was a decrease in in-hospital mortality in intensive care unit patients during the years of observation. This decrease was not associated with hospital teaching status, suggesting no net positive or negative association of the resident work-hours regulations with a major patient-centered outcome.

Figure 1

Flow diagram of selection of patient admissions and hospitals for analysis.

Figure 2. Adjusted in-hospital and ICU mortality*, by year

In-hospital mortality is illustrated in (A). ICU mortality is illustrated in (B). *Mortality is adjusted for gender, APACHE III, length of stay prior to ICU admission, and location prior to admission. Error bars represent the upper and lower limits of the 95% confidence intervals.