Anticholinergics reduce symptoms of overactive bladder

Journal of Family Practice, Sept, 2003 by Sharon See, Kamini Geer

Herbison P, Hay-Smith J, Ellis G, Moore K. Effectiveness of anticholinergic drugs compared to placebo in the treatment of overactive bladder: systematic review. BMJ 2003; 326:841-847.

* PRACTICE RECOMMENDATIONS

Anticholinergic drugs such as tolterodine and oxybutynin produce a small effect on the symptoms of overactive bladder, decreasing slightly the number of episodes of leakage and the frequency of urination. The standard conservative intervention of bladder retraining has not been compared with anticholinergic drugs and their effect in combination has hot been studied.

* BACKGROUND

Clinicians often use anticholinergic agents as the drugs of choice for overactive bladder. However, there is no consensus regarding the efficacy of these drugs in reducing the symptoms of overactive bladder.

* POPULATION STUDIED

Over 6800 patients were enrolled in 32 randomized controlled trials. Most patients were randomized to receive either an anticholinergic or placebo. The trials had variable inclusion and exclusion criteria as well as demographic data. Trial results hot in English were translated.

* STUDY DESIGN AND VALIDITY

The researchers performed a meta-analysis of the data from 32 placebo-controlled, double-blinded clinical trials identified in the Cochrane Incontinence Database. These trials compared the effectiveness of anticholinergic medicines (tolterodine, oxybutynin, trospium chloride, propiverine, emepronium bromide, and propantheline) and placebo in treating overactive bladder in men and women.

Symptoms of overactive bladder include urinary urgency, urge urinary incontinence, urinary frequency, and nocturia. These drugs were used in various dosages and were administered either orally or intravesicularly. The authors of this study assessed the methodological quality of these trials and combined the data from the treatment arms and placebo arms

of these trials.

The majority of trials did not describe the method of masking allocation to treatment group from the enrolling investigator. Therefore, concealed allocation may not have occurred.

The data analyzed were collected from different points in the drug treatment because some researchers gathered data throughout the trial, while some gathered data only at trial conclusion. This variable length of treatment may have affected symptom control. The trials also did hot clearly provide baseline characteristics of enrolled patients, so true trial comparability is unknown. Some results were also reported without measures of variation (eg, confidence intervals), making it difficult for the researchers to evaluate the range of benefit.

* OUTCOMES MEASURED

Primary outcomes were number of leakages, number of voids, and the patients' perception of improvement or cure of their symptoms. Secondary outcomes were volume at first contraction, maximum cystometric capacity, residual volume, and adverse events.

* RESULTS

Treatment decreased episodes of leakage by 1 episode every 2 days and decreased the number of micturitions by 1 every 2 days. Subjects taking anticholinergics also reported fewer subjective symptoms of overactive bladder (relative risk [RR]=1.41; 95% confidence interval [CI], 1.29-1.54). The subjects who received anticholinergics improved maximum cystometric capacity.

No heterogeneity was seen among the trial results. No significant difference in withdrawals due to adverse events was found between drug and placebo groups (RR=1.01; 95% CI, 0.78-1.31).

The most frequently reported adverse effect was dry mouth, which occurred more often in the drug group than the placebo group (RR=2.24-2.92). When elderly patients with polypharmacy were excluded from this analysis, the relative risk of dry mouth increased (2.46-3.36) but the difference was no longer significant.

Sharon See, PharmD, and Kamini Geer, MD, Beth Israel Program in Urban Family Health, Phillips Family Practice, New York, NY. E-mail: kaminigeer@msn.com.