Relative Risk of Adverse Events and Treatment Discontinuations Between Older and Non-Older Adults Treated with Antimuscarinics for Overactive Bladder: A Systematic Review and Meta-Analysis.

INTRODUCTION: Overactive bladder (OAB) affects adults of all ages. The risk for medication-related adverse events (AEs) may differ between age groups, given age-related changes in pharmacokinetics and pharmacodynamics. No previous study has differentiated the risk of AEs between older and non-older adults with OAB. OBJECTIVE: Our objective was to assess the risk of AEs and treatment discontinuations between older and non-older adults with OAB initiated on an antimuscarinic. METHODS: We searched MEDLINE (PubMed interface), Embase, SCOPUS, and Cochrane Central Register for Controlled Trials in a previous analysis in February 2015 and repeated the search in August 2018, with no additional studies identified. Studies that delineated AEs or treatment discontinuations between the older and non-older (age <65 years) subjects were included. RESULTS: Six studies that made nine comparisons between older and non-older subjects met the inclusion criteria. The AEs of dry mouth (46.7%), constipation (10.3%), and headache (7.7%) were most frequently reported. Older subjects were more likely to experience dry mouth (relative risk [RR] 1.09; 95% confidence interval [CI] 1.00-1.19), constipation (RR 1.92; 95% CI 1.52-2.43), dizziness (RR 2.37; 95% CI 1.21-4.62), and urinary retention (RR 4.17; 95% CI 1.76-9.89) than were non-older subjects. Headache was less likely to occur in older subjects (RR 0.58; 95% CI 0.40-0.86). Treatment discontinuations due to AEs were more likely to occur in the older subjects (RR 1.59; 95% CI 1.20-2.11). CONCLUSION: Treatment of OAB with antimuscarinics in the older population resulted in significantly higher rates of AEs, barring headache, when compared with non-older subjects.