Systematic Review: Effects of Resident Work Hours on Patient Safety

Key Summary Points The Accreditation Council for Graduate Medical Education has mandated work hour limitations for all residents in the United States. Evidence about patient safety is insufficient to inform the process of reducing resident work hours. Seven studies have assessed patient safety and interventions to decrease resident work hours. Previous research on interventions to reduce resident work hours is suboptimal and contradictory (some studies suggest improvements in patient safety indicators, while other studies suggest no change or possible harm after interventions were performed). Future research should focus on patient safety indicators as outcomes when interventions to decrease resident work hours are implemented. Several national organizations, including Public Citizen (a consumer watchdog group) (1), the American Medical Student Association (AMSA) (2), and the Committee of Interns and Residents (CIR) (3), have criticized the long hours of residency. Together, these groups unsuccessfully petitioned the Occupational Safety and Health Administration (OSHA) to require resident work hour limitations (1). Some patient safety advocates believe that limiting physician work hours and decreasing fatigue will improve patient safety (4). This widely accepted belief has led to dramatic reform initiated by the Accreditation Council for Graduate Medical Education (ACGME) (5). This reform sought to create a minimum standard for duty hours across all training programs, regardless of specialty. This change occurred nationally on 1 July 2003 (6). The effect of this universal change in resident work hours on patient safety is unknown. A primary concern with the modification of resident work hours is the potential loss of continuity of care (7, 8). Continuity is a core value across specialties, and its preservation has potential benefits and drawbacks for patients, physicians, and the health care system. The trade-off between the positive values of continuity of care and decreasing resident fatigue has important implications for patient safety, both directly (for example, errors) and indirectly (for example, resident health). It is unclear how solutions that provide resident night-float coverage and improve resident mood and satisfaction will affect patient care. The predictable consequence of decreasing hours of care is that multiple physicians must now care for an individual patient; the consequence to patient safety of these several patient hand-offs is unknown. It is difficult to know how to achieve an optimal balance between continuity and fatigue, given that both may have repercussions for patient safety and are optimized in different ways. In the past year, residency programs in all specialties have been investing time and resources to conform to the ACGME's regulations. While the proposed changes to resident work hours have been much debated (7-12), a systematic review of the literature examining the relationship between limiting resident work hours and patient safety will help inform this discussion and guide policymakers (13), program directors, and others who are involved in educating residents. Methods Data Sources We searched the English-language literature about resident work hours for 1966 to March 2004 with MEDLINE, PREMEDLINE (1966 to mid-2002 only), EMBASE, and Current Contents. In March 2004, we re-ran the MEDLINE, EMBASE, and Current Contents searches by using the same strategy. The MEDLINE search was conducted by exploding and combining the following Medical Subject Heading (MeSH) terms: workload; work schedule tolerance; fatigue; mental fatigue; sleep; sleep deprivation; sleep disorders; sleep disorder, circadian rhythm; chronobiology; and personnel staffing and scheduling. We included the following terms in a keyword search: work hours, workload, fatigue, and work schedule. We combined all the keywords and MeSH subheadings. Finally, we combined that list with the combination of the exploded MeSH term education, medical, graduate, and the term internship and residency. The keyword night float was searched separately. We used similar search strategies with the other databases. The list contained more than 1300 references. We hand-searched several journals that are not indexed for 1966 to 2002: Medical Teacher (19791986), Medical Education (19761986), British Journal of Medical Education (19661975), and Teaching and Learning in Medicine (19892002). We also hand-searched several journals (Annals of Internal Medicine, Academic Medicine, Society of General Internal Medicine, Journal of the American Medical Association, and The New England Journal of Medicine) for January to March 2004 to ensure that important relevant articles that were not yet indexed would be included. We identified 8 additional studies of interventions to limit resident work hours. One of these studies reported patient safetyrelated outcomes. We examined the reference lists of all articles included in our review and the reference lists of review articles to identify additional papers. Finally, we asked an expert to review our final bibliography to ensure the completeness of the list of relevant published and unpublished studies. Study Selection We included studies that 1) assessed a system change designed to counteract the effects of work hours, fatigue, or sleep deprivation and 2) included an outcome directly related to patient safety (for example, death, morbidity, and patient care errors). Starting with more than 1200 citations for 1966 to 2002 and 172 citations for 2002 to 2004, we reviewed the abstracts of all relevant articles (Figure). Of these, 343 warranted more detailed review to determine whether they met inclusion criteria (many of the original citations were not research reports). Two authors involved in data abstraction independently reviewed the articles from the first search to ascertain whether they met inclusion criteria. One author reviewed the articles from the second search by using the same inclusion criteria. Figure. The process used to search the literature and select studies for inclusion. Data Abstraction Of the 343 papers reviewed, 42 studies described relevant interventions, and 11 of those evaluated patient outcomes. We eliminated 2 studies because they relied solely on survey reports of errors (1 resident self-report [14] and 1 report of nurses' perceptions of resident errors [15]). We eliminated 2 other papers because they studied patient satisfaction, not safety (16, 17). Thus, we included 7 studies in this review. Two authors abstracted the data from each included article, and 1 author reviewed all studies. We used a standardized abstraction form that included the following information: number of participants, presence or absence of a control group, study design, outcomes, and methodologic concerns. We resolved all disagreements by discussion and consensus. When necessary, we attempted to contact the authors of the studies to provide additional information. Role of the Funding Source The Ann Arbor Veterans Affairs Medical Center/University of Michigan's Patient Safety Enhancement Program had no role in the design, conduct, or reporting of the study or in the decision to submit the manuscript for publication. Data Synthesis We present the results of the 7 intervention studies that assessed patient safety outcomes. The Appendix Table shows the study design, strengths, and weaknesses of each study. No study was a clinical trial. The Table summarizes the studies' diverse interventions. The outcomes also varied considerably from study to study (Table). To clarify our terminology, we use interns to refer to physicians in their first year of postgraduate training and residents for those in at least their second year of postgraduate training. Table. Summary of the Studies Included in the Review: Interventions and Outcomes Appendix Table. Summary of Study Design Strengths and Weaknesses Daigler and colleagues (18) conducted a retrospective cohort study to assess the effect of schedule changes for interns in a pediatrics program that would result in compliance with New York code 405 (the New York state law that limited resident work hours in 1989 [25]). In the preintervention period (19871988), residents worked approximately 100 hours per week and took overnight call every third or fourth night. In the postintervention period (19881989), the interns were scheduled to work less than 70 hours per week. Each week had one 24-hour day, one 16-hour day, one 12-hour day, three 9-hour days, and one day off. The intensive care units continued to have call every third night. The authors reported no difference in mortality, morbidity, or unexpected intensive care unit transfers after the schedule changes occurred. However, this study is flawed because the methods section contains very limited information about the patient sample, data collection, and data analysis. Gottlieb and colleagues (19) used a prospective prepost design to evaluate the effects of schedule changes in an internal medicine program at a Veterans Affairs hospital. These changes consisted of shifting from a call system with interns on call every fourth night and residents on call every eighth night to a system that incorporated a night- float system. The teams in the new system had 7-day cycles with 1 long call day, 3 short call days, and 3 noncall days during each cycle. Short call also occurred on the weekends. Therefore, interns were on call overnight every seventh night while residents were on call overnight every 14th night. Night-float teams admitted all patients after 10 p.m. on Sunday to Thursday. The housestaff reported sleeping substantially more after the intervention (19). The patient-related outcomes studied were medication errors, fevers, deaths, and readmissions. Resource utilization was also studied in the form of length of stay and the numbers of laboratory tests, consultations, and radiographs ordered. Statistically significantly