Admissions to hospital caused by adverse drug reactions: cross sectional incidence study.

The incidence of adverse reactions to drugs has been assessed with prospective epidemiological studies conducted within single units, departments, or hospitals.[1-3] Because of the variability of the results and a lack of representativeness, it is difficult to confidently extrapolate these results to a national level. To calculate the incidence of admissions caused by adverse drug reactions we conducted a prospective cross sectional study of a representative nationwide sample of medical wards in public hospitals.

Methods and results

Between 2 March and 20 April 1998, the study was conducted for 14 days in each of a representative sample of medical departments in French teaching hospitals and general hospitals. The sample size required was calculated from the results of a pilot study.[4] All patients admitted to the departments sampled were included in the study. Each patient was assessed by a team of local clinicians and pharmacologists to determine whether the admission was the result of an adverse drug …