DOES AGE AFFECT THE EFFICACY OF MIRABEGRON IN WOMEN WITH OVERACTIVE BLADDER SYMPTOMS?
KHALIL 1, A. BALACHANDRAN 2, N. L. CURTISS 3, J. DUCKETT 4, M. BASU1;
1Medway NHS Fndn. Trust, Gillingham, United Kingdom, 2Medway Martime Hosp., Kent, United Kingdom, 3London, Dover, United Kingdom, 4Medway NHS Fndn. trust, Gillingham, United Kingdom.
Introduction: Mirabegon acts via the beta 3 receptor, leading to bladder relaxation and relief of overactive bladder (OAB) symptoms. It has been suggested that beta 3 agonists may be preferable to antimuscarinics in older women because they do not have an anti-cholinergic burden, which has been associated with an increase in cognitive decline . Mirabegron has been shown to be an effective treatment for OAB in systematic reviews of randomised controlled trials , however such trials will often exclude older women as well as those with significant co-morbidities. A randomised controlled trial also has a high placebo effect due to the frequent interactions with healthcare professionals. If mirabegron is to be considered as an effective alternative to antimuscarinics in older women, it is important to assess whether its efficacy is affected by the age of the women being treated. This study evaluated the effect of age on treatment success in a heterogenous group of women treated with mirabegron.
Objective: To evaluate whether treatment response to mirabegron is affected by age in an unselected cohort of women with OAB symptoms.
Methods: This was a secondary analysis of a prospective observational study of women with OAB symptoms, which had proved refractory to conservative management. Women with stress predominant mixed incontinence, and bladder pathology of unknown origin were excluded. All women underwent filling and voiding subtraction cystometry prior to further treatment. Women were treated with mirabegron 50mg once daily, and outcomes were evaluated after 6 weeks’ treatment. The primary outcome measure was change in symptoms after 6 weeks’ treatment as indicated by the patient’s response to the Patient Global Impression of Improvement (PGI-I). The cohort was subdivided by age, and evaluated for any effect of age on treatment response. Clinical and demographic data were also noted in order to evaluate for any measurable effect on treatment efficacy. A Mann Whitney test was used to evaluate non-parametric continuous data, a student’s t test was used for parametric continuous data and a Fisher’s Exact test was used for categorical data. Under current UK regulations, this evaluation was classified as a service evaluation and was therefore exempt from formal ethical approval.
Results: Complete data were available for 162 women. The mean age of the cohort was 53.9 years (range 20-87 years). 20.8% (34/162) of the cohort was above the age of 65. 58.3% (94/162) of women were responders to mirabegron. Women aged 65 were no more or less likely to be responders than those aged less than 65 (p= 0.27). There was no significant difference in mean age between responders and non-responders (54.5 vs 54.1, p= 0.90). There was no significant difference in the post treatment change in UDI-6 scores between women above and below 65 years old (p= 0.11). A diagnosis of diabetes, a history of previous surgery and the presence of detrusor overactivity had no effect on treatment success in women over 65.
Conclusions: In this cohort of women, age was not associated with treatment response. Mirabegron has similar efficacy for treatment of OAB symptoms in women of ages above and below 65 years old. Based on these data, women over the age of 65 can be reassured that their chances of responding to mirabegron are no different to those of younger women, with the potential benefit of not adding to any pre-existing anticholinergic burden from other drugs.
References: 1. Pharmacotherapy 2016; 36(11): 1123-1131 2.
2. Urol Int 2014; 93(3): 326-337