Objective: To evaluate patient-reported reasons for discontinuing antimuscarinic prescription medications for overactive bladder (OAB).
Patients and methods: A phase 1 screening survey was sent to a representative sample of 260 000 households in the USA to identify patients using antimuscarinic agents for OAB. A detailed phase-2 follow-up survey was sent to 6577 respondents with one or more antimuscarinic prescriptions for OAB in the 12 months before the phase 1 survey. The follow-up survey included questions about demographics, clinical characteristics, antimuscarinic use, beliefs about OAB, treatment expectations, OAB symptom bother, and pre-coded reasons for discontinuation. Patients who reported discontinuing one or more OAB medication during the 12 months before phase 2 were grouped by reason, using latent class analysis (LCA); the Lo-Mendell-Rubin likelihood statistical test was used to determine the number of classes. Conditional probabilities of reasons for discontinuation were calculated for each class. Multivariable logistic regression was used to assess the influence of demographic and clinical characteristics on class assignment.
Results: In all, 162 906 (63%) and 5392 (82%) useable responses were returned in phases 1 and 2, respectively; the demographics were similar in respondents and nonrespondents in both phases. In all, 1322 phase 2 respondents (24.5%) reported discontinuing one or more antimuscarinic drugs during the 12 months before phase 2. LCA identified two classes (Lo-Mendell-Rubin statistic, P = 0.01) based on reasons for discontinuation. Most respondents (89%) reported discontinuing OAB medication primarily due to unmet treatment expectations and/or tolerability; many respondents in this class switched to a new antimuscarinic agent. A smaller group (11%) indicated a general aversion to taking medication. Age, sex, race, income, and history of incontinence were not predictive of class assignment.
Conclusions: Expectations about treatment efficacy and side-effects are the most important considerations in discontinuing OAB medications for most patients. Interventions to promote realistic expectations about treatment efficacy and side-effects might enhance adherence.