Drug-related deaths among inpatients: a meta-analysis.

Purpose: To estimate the prevalence of drug-related deaths with regard to total hospital mortality and to explore the heterogeneity in its estimation through subgroup analysis, univariate and multivariate analysis.

Methods: Two investigators independently searched the PubMed and Google Scholar databases with appropriate key terms to identify observational and randomised studies assessing drug-related problems. The prevalence of drug-related deaths was estimated using a double arcsine method. The heterogeneity was explored through subgroup and univariate analysis for the following study characteristics: study design, age group, study ward, study region, types of drug-related problems, study duration, sample size and study period. The study variables showing significant effects were further explored through a multivariable regression model. The percentage of preventable drug-related deaths was explored as a secondary objective.

Results: Of the 480 full-text articles assessed, 23 studies satisfying the selection criteria were included. The mean percentage of drug-related deaths was 5.6% (95% CI: 3.8-7.6%; I = 96%). The univariable analysis showed study design (regression coefficient: 4.31) and study wards (regression coefficient: - 6.37) as heterogeneity modifiers. In the multivariable model, only the study ward was considered a significant predictor of drug-related deaths (regression coefficient: - 5.78; p = 0.04). The mean percentage of preventable drug-related deaths was 45.2% (95% CI: 33.6-57.0%; I = 60%).

Conclusion: Drug-related problems are an important cause of mortality. The variability in its estimation could be explained by admission wards.