[Incidence rate of adverse drug effects in a hospital emergency unit and its associated factors]

Introduction: Adverse drug effects (ADEs) are the reason for 0.86% to 38.2% of hospital emergency admissions, and a large percentage of them are avoidable. Rational prescription and pharmacotherapy monitoring decrease the appearance of such health problems.

Method: Study performed in a tertiary hospital emergency unit with patients selected using a two-phase random sample. The information was obtained from a validated questionnaire and from the clinical history. The data were grouped according to the following cause-effect schema: 1-Potential risk factors for an ADE. 2-Effects likely to be caused by drugs. 3-Consequences of ADEs. 4-Potential confounding factors. The information obtained was evaluated by four independent evaluators using the Dader method.

Results: 840 patients were included in the study, and 33% of them came to the emergency unit due to an ADE. ADEs were more frequently observed in female patients, those with higher drug consumption, older patients, those with an underlying illness and in those from underprivileged backgrounds. The factors determining risk of an ADE are the quantity of drugs consumed, sex and the health practices index.

Discussion: One third of hospital emergency admissions were due to ADEs, and these were associated with the same factors found in other studies (number of drugs consumed, female sex, age and social background). In addition, we observed that ADEs are predominant in patients with low values on the health practices index, and in those with underlying illnesses.