Hospitalwide adverse drug events before and after limiting weekly work hours of medical residents to 80

Adverse drug events (ADEs) at a hospital before and after the weekly work hours of medical residents were limited to 80 were studied. The study population included all adults admitted to a 750-bed academic tertiary care hospital where resident physicians provide direct care under the supervision of faculty attending physicians. The six-month period after implementation of the 80-hour work limit (July 1 to December 31, 2003) was compared with the same six-month period one year before implementation (July 1 to December 31, 2002). There were no significant differences between study periods in any measured variables, including number of confirmed ADEs (194 before, 172 after), number of ADEs per 1000 patient days (1.3 before, 1.1 after), and number of preventable ADEs (21 before, 22 after). Hospitalwide ADEs remained constant despite limiting of resident physician weekly work hours to 80.