Effect of anticholinergic use for the treatment of overactive bladder on cognitive function in postmenopausal women

Overactive bladder (OAB) is a common condition affecting the elderly. The mainstay of treatment for OAB is medical therapy with anticholinergics. However, adverse events have been reported with this class of drugs, including cognitive changes.

The objective of this study was to investigate the effect of an anticholinergic medication, trospium chloride, on cognitive function in postmenopausal women being treated for OAB.

This was a prospective cohort study conducted at a urogynaecology clinic at one academic medical centre from January to December 2010, with 12-week follow-up after medication initiation. Women aged 55 years or older seeking treatment for OAB and opting for anticholinergic therapy were recruited. Baseline cognitive function was assessed via the Hopkins Verbal Learning Test-Revised Form (HVLT-R) [and its five subscales], the Orientation, Memory & Concentration (OMC) short form, and the Mini-Cog evaluation. After initiation of trospium chloride extended release, cognitive function was reassessed at Day 1, Week 1, Week 4 and Week 12. Bladder function was assessed via three condition-specific quality-of-life questionnaires. Secondary outcomes included change in bladder symptoms, correlation between cognitive and bladder symptoms, and overall medication compliance. The main outcome measure was change in HVLT-R score at Week 4 after medication initiation, compared with baseline (pre-medication) score.

Of 50 women enrolled, 35 completed the assessment. The average age was 70.4 years and 77.1% had previously taken anticholinergic medication for OAB. At enrollment 65.7% had severe overactive bladder and 71.4% had severe urge incontinence. Cognitive function showed an initial decline on Day 1 in HVLT-R total score (p = 0.037), HVLT-R Delayed Recognition subscale (p = 0.011) and HVLT-R Recognition Bias subscale (p = 0.01). At Week 1 the HVLT-R Learning subscale declined from baseline (p = 0.029). All HVLT-R scores normalized by Week 4. OMC remained stable throughout. The Mini-Cog nadired at a 90.9% pass rate at Week 4. OAB symptoms did not improve until Week 4, based on questionnaire scores (p < 0.05).

Cognitive function exhibited early changes after initiation of trospium chloride but normalized within 4 weeks. Cognitive changes occurred weeks prior to OAB symptom improvement. Surveillance for cognitive changes with anticholinergic use should be part of OAB management.