Adverse Drug Events by Sex After Adjusting for Baseline Rates of Drug Use

Data from pharmacovigilance databases like the U.S. FDA Adverse Event Reporting System (FAERS) are widely cited as evidence for claims that women experience adverse drug events (ADEs) at as high as twice the rate of men. Biological factors are typically hypothesized to explain these sex differences. However, many factors could influence the distribution of ADE reports by sex, including well-known disparities in the rates at which men and women use prescribed drugs. This study examined ADEs reported by sex in the FAERS database after adjusting for drug use by men and women, finding that adjusting pharmacovigilance data from FAERS with nationally representative data on sex disparities in usage of drugs greatly attenuates the apparent sex disparity in ADE reports, reducing the gap in the median number of ADEs for women compared to men from 45.1% to 15.0%. The commonly cited claim that women experience 1.5 to 2 times the number of ADEs as men was demonstrated to be highly unlikely, with a probability of less than 5% after accounting for drug usage. After accounting for underlying drug use, reported numbers of ADE were similar between men and women when looking across drugs, suggesting that gender/sex disparities in drug use may largely explain observed gender/sex disparities in ADEs. Rushovich, Gompers, and Lockhart are co-first authors of this publication, and the article is available Open Access.