Background: A higher mortality rate in women than in men treated with digitalis has been described. We hypothesized that this result could be due in part to an increased susceptibility of women to adverse events (AEs) from digitalis.
Objective: The aim of this study was to compare the incidence of AEs related to digitalis in women and men.
Methods: This was an observational study conducted in geriatrics and internal medicine acute-care wards located throughout Italy. We used the data of the Gruppo Italiano di Farmacoepidemiologia nell'Anziano (Italian Group of Pharmacoepidemiology in the Elderly), a collaborative study group on drug use and adverse drug reactions in hospitalized adults that performed 6 different surveys between 1988 and 1998. Adults who were taking digitalis at the time of admission or during the hospital stay were studied, with no other inclusion or exclusion criteria. The proportion of AEs to digitalis diagnosed at the time of admission or during the hospital stay was compared in men and women. Information on AEs was collected using a structured questionnaire at admission and during the hospital stay. A logistic regression model was used to evaluate the association between sex and AE(s) to digitalis, corrected for potential confounding variables.
Results: The total sample size was 9626 patients. Women received a higher weight-adjusted dose of digitalis compared with men (0.0027 mg/kg per day vs 0.0025 mg/kg per day; P < 0.001). Overall, 199 AEs to digitalis were diagnosed. Women were more likely than men to suffer from an AE to digitalis (odds ratio, 1.51; 95% CI, 1.12-2.02). This finding was confirmed after correction for dose of digitalis, age, physical and cognitive impairment, atrial fibrillation, chronic obstructive pulmonary disease, glomerular filtration rate, and use of amiodarone, beta-blockers, nondihydropyridine calcium channel blockers, and potassium-sparing diuretics (odds ratio, 1.58; 95% CI, 1.01-2.48).
Conclusions: In this sample of hospitalized adults in Italy, we found a higher incidence of AEs to digitalis in women than in men.