iS IT POSSIBLE TO CURE THE SYMPTOMS OF THE OVERACTIVE BLADDER IN WOMEN ?
KRHUT1, A. MARTAN 2, R. ZACHOVAL 3, T. HANUS 4, L. HORCICKA 5, K. SVABIK 6, M. HALASKA 7;
1Urology, Univ. Hosp., Ostrava, Czech Republic, 2Dpt. of Obstet. and Gynecol., 1st Faculty of Med., Prague, Czech Republic, 3Dept. of Urology, Thomayer Hosp., Prague, Czech Republic, 4Dpt.of Urology, Univ.Hosp., Praha 2, Czech Republic, 5GONA s.r.o., Praha, Czech Republic, 6Charles Univ. in Prague, Gen. Univ. H, Prague, Czech Republic, 7Charles Univ., Prague 8, Czech Republic.
Introduction: Overactive bladder (OAB) is a debilitating condition affecting quality of life of 10-12% of adult population. Pharmacologic treatment using anticholinergics is considered effective and safe according many clinical studies, however substantial proportion of patients discontinues the treatment. Even though most often reported reason for discontinuation of anticholinergics is lack of efficacy and/or side effects, significant number of patients report, that they do not take the medication anymore because their symptoms disappeared/were cured.  When compared to anticholinergics, mirabegron seems to have comparable efficacy and superior tolerability in the OAB treatment. The conclusive data about possibility of disappearance of OAB symptoms in the patients treated with mirabegron have not yet been reported.
Objective: To evaluate the possibility of withdrawing the medication in OAB patients whose symptoms subsided while treated using mirabegron.
Methods: Total of 159 female patients (age 62.9 ± 12.36) with OAB symptoms were included into the study. All were prescribed mirabegron 50 mg/day (Time point - T1). All patients returned for a follow-up visit at month 1,3,6,12,18 (T2) and 21(T4) after the start of the treatment. Data obtained from the voiding diaries (number of voids per 24 hour period, number of urgency episodes per 24 hour period, severity of urgency episode, number of nocturia episodes per 24 hour period), Patients’ Perception of Bladder Condition (PPBC), OAB questionnaire (OAB-q), Urgency Bother-Visual Analog Scale (UB-VAS) and Treatment Satisfaction - Visual Analog Scale (TS-VAS) were used to evaluate the treatment efficacy at every follow- up visit. Reduction of UB-VAS was considered main criterion of successful treatment. On the visit at month 18 all patients with UB-VAS < 50% were advised to stop the medication with mirabegron. They were allowed to start taking medication again, at their discretion, if the OAB symptoms reappeared or worsened. The patients were instructed to collect all data (voiding diary, OAB-q, PPBC, UB-VAS) immediately before they started taking medication again (T3). Study design was approved by Institutional Review Board. Statistical analysis was performed using IBM SPSS v.20.0. Proportion of patients having wet OAB was tested using chi-square test. ANOVA analysis was used for evaluation of differences between groups of patients in general, two-sample t-test was used for evaluation of significance of differences between individual groups of patients.
Results: Sixty-four patients (64/159; 40.3%) discontinued the treatment due to variable reasons, 39 patients (39/159; 24.4%) were advised to increase the dose of mirabegron or were switched to another medication/treatment (combination therapy mirabegron + antimuscarinics, neurostimulation). Total 56 of 159 (35.3%) patients took mirabegron 50 mg continuously between T1 and T2. Total 17 of 56 patients (30.4%) did not meet the criteria for mirabegron discontinuation (Group A). Twenty four of 56 patients (42.9%) stopped the medication, but started again later on (Group B). Average time span between T2 to T3 was 53,9 days. Fifteen of 56 patients (26,8%) stopped medication without starting it again before T4 (Group C). Average time span between T2 to T4 in Group C was 124.7 days. Group C represents only 9.4% of patients enrolled in the study (15/159). Comparison of treatment outcomes within individual groups is shown in Table 1. When assessing the parameters which could predict successful withdrawal of medication only the total number of severe urgency episodes was identified.
Conclusions: Only small percentage of OAB patients is able to discontinue the mirabegron due to symptom disappearence/symptom cure. These were mainly patients suffering from mild OAB symptoms (low number of severe episodes of urgency).
References: 1. Benner JS, Nichol MB, Rovner ES, et al: Patient-reported reasons for discontinuing overactive bladder medication. BJU Int. 2010;105(9):1276-82.