"July effect": impact of the academic year-end changeover on patient outcomes: a systematic review.

BACKGROUND It is commonly believed that the quality of health care decreases during trainee changeovers at the end of the academic year. PURPOSE To systematically review studies describing the effects of trainee changeover on patient outcomes. DATA SOURCES Electronic literature search of PubMed, Educational Research Information Center (ERIC), EMBASE, and the Cochrane Library for English-language studies published between 1989 and July 2010. STUDY SELECTION Title and abstract review followed by full-text review to identify studies that assessed the effect of the changeover on patient outcomes and that used a control group or period as a comparator. DATA EXTRACTION Using a standardized form, 2 authors independently abstracted data on outcomes, study setting and design, and statistical methods. Differences between reviewers were reconciled by consensus. Studies were then categorized according to methodological quality, sample size, and outcomes reported. DATA SYNTHESIS Of the 39 included studies, 27 (69%) reported mortality, 19 (49%) reported efficiency (length of stay, duration of procedure, hospital charges), 23 (59%) reported morbidity, and 6 (15%) reported medical error outcomes; all studies focused on inpatient settings. Most studies were conducted in the United States. Thirteen (33%) were of higher quality. Studies with higher-quality designs and larger sample sizes more often showed increased mortality and decreased efficiency at time of changeover. Studies examining morbidity and medical error outcomes were of lower quality and produced inconsistent results. LIMITATIONS The review was limited to English-language reports. No study focused on the effect of changeovers in ambulatory care settings. The definition of changeover, resident role in patient care, and supervision structure varied considerably among studies. Most studies did not control for time trends or level of supervision or use methods appropriate for hierarchical data. CONCLUSION Mortality increases and efficiency decreases in hospitals because of year-end changeovers, although heterogeneity in the existing literature does not permit firm conclusions about the degree of risk posed, how changeover affects morbidity and rates of medical errors, or whether particular models are more or less problematic. PRIMARY FUNDING SOURCE National Heart, Lung, and Blood Institute.