Older People's Preferences for Side Effects Associated with Antimuscarinic Treatments of Overactive Bladder: A Discrete-Choice Experiment.

INTRODUCTION: Understanding the importance older people attribute to the different side effects associated with oral antimuscarinic treatments for overactive bladder (OAB) could help inform prescribers, healthcare policy makers and the drug industry.

OBJECTIVE: Our objective was to quantify the importance of the most prevalent cognitive and side effects of oral antimuscarinic treatments for OAB in older people.

METHODS: We conducted a discrete-choice experiment (DCE) with the assistance of an interviewer with community-dwelling and hospitalized older people aged >65 years. The DCE involved two hypothetical drugs for imaginary OAB, with three levels of four side effects for each drug, and the International Consultation on Incontinence Questionnaire-Overactive Bladder and EuroQol 5-Dimensions (EQ-5D) questionnaire were also administered. Data were analysed using a conditional logit model.

RESULTS: In total, 276 older people participated in the study. The median age was 75 years (interquartile range [IQR] 69-80), 63% were women and 21% had OAB syndrome. The most unwanted side effect in the choice of antimuscarinics for OAB was severe cognitive effects, followed by severe constipation, severe blurred vision, severe dry mouth, moderate cognitive effects and moderate constipation. Severe cognitive effects were at least 1.7 times as important as severe constipation. Exploratory subgroup analysis showed that none of the attributes was found to be significant in people who scored as anxious or depressed on the EQ-5D, and preferences about cognitive effects, constipation and blurred vision were equal in people with and without OAB.

CONCLUSION: Older people attribute more importance to loss of cognitive function as a possible side effect of antimuscarinic treatment than to the three most prevalent possible side effects of this treatment.