Objective: The occurrence of drug adverse events in hospital settings is high and generates cost excess. The purpose of the study was to identify drug-related events during hospital admissions and to estimate their prevalence.
Methods: A retrospective study was carried out in the State of Rio de Janeiro, Southeastern Brazil. Hospitalizations from the Brazilian Health System's national hospital database during the period between 1999 and 2002 were assessed. Admitted cases including suspected drug adverse event cases with ICD-10 (2000) coding in the main diagnosis and/or secondary diagnosis fields were included in the study. Means and standard deviations of continuous variables as well as the statistical significance of differences were estimated using variance analysis (ANOVA with a 95% confidence interval).
Results: There were identified 3,421 drug-related adverse events, and a prevalence of 1.8 cases per 1,000 hospitalizations was estimated. Most cases occurred in males (64.5%) admitted in contracted (34.9%) and local public hospitals (23.1%) in the departments of psychiatry (51.4%) and internal medicine (45.2%), of them, 84.1% were discharged. Most of them were adverse drug reactions or drug poisoning, and there were significant difference (p<0.000) regarding age and length of stay between these categories. Patients having adverse events were younger (35.8 vs 40.5 years old) and stayed longer in hospital (26.5 vs 5.0 days).
Conclusions: The frequency of drug adverse events, although lower than those findings of international studies, is significant. National hospital admission database was considered useful in the study of drug-related events.