Contribution of adverse drug reactions to hospital admission of older patients.

Objective: to describe the severity of adverse drug reactions as a factor in hospital admission of older patients, and to identify risk indicators for severe adverse drug reactions in these patients. Design: observational cross-sectional study. Setting: Five wards in a university hospital in the Netherlands. Subjects: patients aged 70 and over admitted to general medical wards. Methods: use of statistical comparison and Kramer’s algorithm. Results: a severe adverse drug reaction was present in 25 (24%) of 106 patients. Thirteen patients (12%; 95% confidence interval 6.1‐18.6%) were admitted probably because of an adverse drug reaction. Risk indicators for a severe adverse drug reaction were a fall before admission (odds ratio 51.3, P o 0:006), gastrointestinal bleeding or haematuria (odds ratio 19.8, P < 0.001) and the use of three or more drugs (odds ratio 9.8, P o 0:04). Conclusion: adverse drug reactions are an important cause of hospital admissions in older people. A fall before admission may indicate a severe adverse drug reaction.