Consequently, the authors sought to determine the cognitive effect, safety, and tolerability of 5 mg/day oral extended-release oxybutynin (the most commonly prescribed dosage) in cognitively impaired older nursing home residents who have UUI.
Subjects were eligible if they:
- were 65 years or older
- had UUI
- lived in a nursing home longer than 3 months
- had cognitive impairment.
Women already being treated for urinary incontinence, those who had an indwelling Foley catheter or urinary retention, and those who were bed-bound or incommunicative were excluded.
Fifty women, mean age 88.6 years (SD, ±6.2), from 12 nursing home facilities, agreed to participate. They were further stratified based on the score of a Mini-Mental State Exam (MMSE): 13 had severe cognitive impairment (MMSE score, 5–10) and 37 had mild or moderate impairment (score, 11–23).
Subjects were randomized to 4 weeks’ treatment with either 5 mg/day oral extended-release oxybutynin or one placebo tablet daily. A nurse practitioner who was blinded to randomization collected all data. The Confusion Assessment Method (CAM) algorithm, MMSE, and Severe Impairment Battery (SIB) were used to assess cognitive decline. The Brief Agitation Rating Scale (BARS) assessed agitation.
No baseline differences were noted with regard to: age; demographic, functional, and neuropsychiatric characteristics; clinical factors predisposing to delirium; and serum anticholinergic activity. Adherence was similar in the treatment (97%) and placebo (97.4%) groups.
Finding: Cognitive impairment. Treatment and placebo groups in the baseline mild-or-moderate stratum (by MMSE) showed equivalent mean changes in CAM scores at all time points. Because of the small sample size, however, CAM score equivalence could not be definitively determined for the groups in the severe impairment stratum. Evaluation of mean MMSE and BARS scores showed no significant changes between groups.
Finding: Tolerability. Excellent tolerability was noted in the treatment group: 96% of subjects completed the trial (compared with 92% of the placebo group). No difference in the rate of adverse events was noted between treatment and placebo groups; of adverse events recorded, 90% were judged “mild” by the investigators. Constipation and dry mouth were most common.
Finding: Falls. More than half—54%—of subjects in both groups experienced at least one fall during the trial or during the preceding or following 3 months. Despite this, no difference in the rate of falls between the treatment and placebo groups was noted. Furthermore, regression analysis revealed no treatment or period effect on falls per month across the time of observation.
Conclusions. Treatment with 5 mg/day oral extended-release oxybutynin in older patients with some cognitive impairment is well tolerated, the study’s findings suggest, with minimal risk of further cognitive decline or delirium over the short term. The potential that long-term therapy has to harm cognitive function remains, however; data on long-term treatment are needed to illuminate that area.
The authors also address the importance of dosing, especially over time, and discuss the lower potential of newer-generation anticholinergics to produce cognitive impairment.
A limited number of articles in the medical literature address anticholinergics in an older population, specifically, and only a few of those evaluated the effects of the drugs on cognitive function. By investigating patients who had an existing cognitive impairment, the authors of this article were able to target a cohort at risk of further cognitive impairment from medication use—thereby giving further weight to their findings of no significant effect.
Main strengths and limitations of the study. The investigators used validated, standardized cognitive tests that were administered by a uniform blinded evaluator in a randomized, controlled trial. The study was limited, however, because patients were evaluated only over a relatively short period (1 month) and because the efficacy of therapy was not addressed.
Further studies of anticholinergic medications, using the same rigorous scientific approach that these investigators applied, are needed to address 1) the long-term efficacy of oxybutynin and similar agents and 2) the cognitive effects of long-term treatment in this older population.
WHAT THIS EVIDENCE MEANS FOR PRACTICE
Further impairment is unlikely over the short term when a cognitively impaired nursing home patient who has urge urinary incontinence is treated with 5 mg/day oral extended-release oxybutynin.—JOHN P. JUDD, MD, AND CINDY L. AMUNDSEN, MD