Survival study of treatment adherence by patients given oral oxibutynin for hyperhidrosis.

INTRODUCTION: In recent years, increasing use has been made of oral anticholinergics such as oxybutynin for the management of hyperhidrosis. The primary aim of this study is to determine the variables associated with adherence to this treatment, and secondarily to obtain data on its effectiveness, safety and adverse effects. MATERIAL AND METHODS: This is a prospective study of patients with hyperhidrosis, at any location, receiving treatment with oral oxybutynin in the period 2007-2016. Epidemiological variables, treatment details, effectiveness and adverse effects were recorded. Effectiveness was determined according to the Hyperhidrosis Disease Severity Scale (HDSS) at baseline, at 3 and 12 months and in successive visits. A descriptive analysis was performed, and Cox's bivariate and multivariate regressions were calculated to determine the variables associated with treatment adherence. RESULTS: A total of 201 patients (140 women) with a mean age of 34 years were included. The mean initial HDSS score was 3.8, and the median follow-up period was 29 months. At 3 months, 84.57% of the patients had responded to treatment (excellent response: 72.94%), but adverse effects were reported by 68.2%. At 12 months, 54.23% had responded (excellent response: 79.82%), with adverse effects in 75.2%. The main variable associated with greater adherence was affected areas: palms of the hands and soles of the feet. The following variables were associated with poorer adherence: onset of hyperhidrosis in adolescence, failure to provide an incrementally increasing, individualized dose, initial HDSS score of 3 and partial initial response. The multivariate analysis confirmed the association between the onset of hyperhidrosis during adolescence, the failure to provide a progressively increasing dose and palmar affectation. DISCUSSION: This study was conducted to identify the variables associated with adherence to treatment by hyperhidrosis patients treated with oral oxybutynin. This information would facilitate selection of patients for this treatment and enhance our understanding of the biological behaviour of such anticholinergics when used to treat hyperhidrosis.