Adherence to antimuscarinics in children with overactive bladder

Adherence to antimuscarinics for the treatment of overactive bladder is known to be low in adults but there is scarce data on adherence in paediatric patients. Our objectives were to evaluate the adherence of children to antimuscarinics and to identify influencing factors.

Children aged 5 to 18 years and treated with an antimuscarinic agent for at least 6 months were recruited at a routine visit and had to fill out a questionnaire. Their pharmacists were then contacted to inquire about prescription renewals since the beginning of treatment. The medication possession ratio was calculated and grouped by time blocks of 1, 3, 6 and 12 months. The pharmacists were contacted again 6 months after the recruitment visit. A medication possession ratio ≥ 80% was considered as good adherence.

Seventy-two patients were recruited with a mean age of 10.1 years. The self-reported adherence was 93%. Prior to the questionnaire, the medication possession ratio was ≥ 80% in 36%, 57%, 64% and 74% of cases in blocks of 1, 3, 6 and 12 months, respectively. After the questionnaire, the medication possession ratio improved to 53%, 65% and 71% for blocks of 1, 3 and 6 months, respectively. No influencing factors were identified.

Measured adherence to antimuscarinics in children with overactive bladder is higher than in adults but significantly lower than the self-reported adherence. Good self-reported adherence must be questioned to avoid unnecessary dose escalation or change of medication. Strategies to increase medication adherence are required to improve treatment efficacy.