Objective: To study the relation between housestaff coverage schedules and the occurrence of preventable adverse events.
Design: Case-control study.
Setting: Urban teaching hospital.
Patients: All 3146 patients admitted to the medical service during a 4-month period.
Measurements: A previously tested confidential self-report system to identify adverse events, which were defined as unexpected complications of medical therapy that resulted in increased length of stay or disability at discharge. A panel of three board-certified internists confirmed events and evaluated preventability based on case summaries. Housestaff coverage was coded according to the day in the usual intern's schedule and to cross-coverage status. Cross-coverage was defined as care by a house officer who was not the patient's usual intern and not a member of the usual intern's patient care team. Coverage for an adverse event was assigned according to who was covering during the proximate cause of that event. Clinical data were collected for each patient and two matched controls.
Results: Of the 124 adverse events reported and confirmed, 54 (44%) were judged potentially preventable. In the univariate analysis, patients with potentially preventable adverse events were more likely than their controls to be covered by a physician from another team at the time of the event (26% compared with 12% [odds ratio, 3.5; P = 0.01]). In the multivariate analysis, three factors were significant independent correlates of potentially preventable adverse events: cross-coverage (odds ratio, 6.1; 95% CI, 1.4 to 26.7), Acute Physiology and Chronic Health Evaluation II score (odds ratio per point, 1.2; CI, 1.1 to 1.4), and history of gastrointestinal bleeding (odds ratio, 4.7; CI, 1.2 to 19.0).
Conclusion: Potentially preventable adverse events were strongly associated with coverage by a physician from another team, which may reflect management by housestaff unfamiliar with the patient. The results emphasize the need for careful attention to the outcome of work-hour reforms for housestaff.