Hypothesis / aims of study
Overactive bladder (OAB) affects 17-41% of older adults in community dwelled settings. For several years, antimuscarinics have been validated as the first-line medical treatment for OAB. Despite abundant data obtained from clinical trials provisions the use of antimuscarinics, investigation about the effect of this drug on cognitive function in the elderly remains scarce. This study aims to investigate the effect of antimuscarinics therapy on cognitive functions in OAB geriatric patients.
Study design, materials and methods
This study design is a systematic review and meta-analysis. Studies were collected using several search engines; those were PubMed, Science Direct, Cochrane, and EBSCOhost using predetermined MeSH keywords with Boolean operators. The selection of studies was done by three reviewers. Studies that fulfilled the inclusion and exclusion criteria underwent a full-text review. For every selected full text, we extracted the following data is available: patients demographics, types of antimuscarinics used, placebo, dose, follow-up period, and Mini-Mental State Examination (MMSE) total score
Results
A total of 146 publications were initially retrieved (Figure 1). Of these, 106 studies were excluded due to duplication. Moreover, 28 were excluded during title and abstract screening. Eight studies underwent full-text appraisal, both qualitative and quantitative analysis. There were 8 antimuscarinic agents evaluated in the studies, including Oxybutynin, Darifenacin, Tolterodine, Trospium, Imidafenacin, Propiverine hydrochloride, Fesoterodine, and Solifenacin.
Interpretation of results
Esin et al investigated the effect of antimuscarinic medications on elderly cognitive functions. It was shown that no cognitive impairment was observed in the patients involved in the study who were using these medications. No cognitive impairment was observed in the study population who had dementia at the beginning of the study. From the antimuscarinic medications being used in the study, the oxybutynin and darifenacin group was shown to significantly decrease MMSE scores.
CNS adverse effects such as cognitive impairment might occur because many antimuscarinics can cross the blood-brain barrier. This issue is addressed as a serious consideration in antimuscarinic therapy for elderly OAB patients. The guidelines often recommended oxybutynin. However, a high incidence of cognitive impairment is noted with the administration of this drug. Therefore, administration of oxybutynin is not recommended in frail elderly OAB patients.
Oxybutynin is a highly lipophilic compound, which allows it to cross the blood-brain barrier and causes effects on the central nervous system (CNS). The high lipophilicity, neutrality, and small molecular size of oxybutynin may allow the drug to cross the blood-brain barrier and skin more easily relative to other antimuscarinic agents.