Persistence of antimuscarinic drug use

Abstract

Purpose: Evidence suggests antimuscarinic drugs for the overactive-bladder syndrome only confer modest improvements in quality of life. We wanted to describe the persistence of therapy, including an extended analysis beyond the 1-year follow-up employed in other studies.

Methods: All prescriptions for drugs in ATC category G04BD were retrieved for the period 1999-2006 from a regional database with complete capture of all reimbursed prescriptions. Kaplan-Meyer curves were generated for duration of treatment for each substance and analyzed for determinants of termination.

Results: With the exception of trospium chloride, all drugs had continuation rates of less than 50% at 6 months, less than 25% at 1 year, and less than 10% at 2 years and longer. Trospium chloride, however, exhibited continuation rates of 46% at 6 months, 36% at 1 year, 22% at 2 years, and 16% at 3 years.

Conclusions: In a setting of socialized medicine, we found higher continuation rates than previously published. Interestingly, we found that one of the older drugs on the market, trospium chloride, had a strikingly longer retention rate than other drugs.