Oral anticholinergic drugs versus placebo or no treatment for managing overactive bladder syndrome in adults

Background: Around 16% of adults have symptoms of overactive bladder (OAB; urgency with frequency and/or urge incontinence), with prevalence increasing with age. Anticholinergic drugs are commonly used to treat this condition. This is an update of a Cochrane Review first published in 2002 and last updated in 2006.Objectives: To assess the effects of anticholinergic drugs compared with placebo or no treatment for treating overactive bladder syndrome in adults.Search methods: We searched the Cochrane Incontinence Specialised Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In-Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, WHO ICTRP and handsearching of journals and conference proceedings (searched 14 January 2020), and the reference lists of relevant articles. We updated this search on 3 May 2022, but these results have not yet been fully incorporated.Selection criteria: We included randomised or quasi-randomised trials in adults with overactive bladder syndrome that compared an anticholinergic drug alone with placebo treatment.Data collection and analysis: Two review authors independently assessed eligibility and extracted data from the included studies, including an assessment of the risk of bias. We assessed the certainty of the body of evidence using the GRADE approach. We processed data as described in the Cochrane Handbook for Systematic Reviews of Interventions.Main results: We included 104 studies, 71 of which were new or updated for this version of the review. Although 12 studies did not report the number of participants, there were 47,106 people in the remainder of the included studies. The majority of the studies had insufficient information to allow judgement of risk of bias and we judged them to be unclear for all domains. Nine anticholinergic drugs were included in these studies: darifenacin; fesoterodine; imidafenacin; oxybutynin; propantheline; propiverine; solifenacin; tolterodine and trospium. No studies were found that compared anticholinergic drugs to no treatment.At the end of the treatment period, anticholinergics may slightly increase condition-specific quality of life (mean difference (MD) 4.41 lower, 95% confidence interval (CI) 5.28 lower to 3.54 lower (scale range -100 to 0); 12 studies, 6804 participants; low-certainty evidence). Anticholinergics are probably better than placebo in terms of patient perception of cure or improvement (risk ratio (RR) 1.38, 95% CI 1.15 to 1.66; 9 studies, 8457 participants; moderate-certainty evidence), and the mean number of urgency episodes per 24-hour period (MD 0.85 lower, 95% CI 1.03 lower to 0.67 lower; 23 studies, 16,875 participants; moderate-certainty evidence).Compared to placebo, anticholinergics may result in an increase in dry mouth adverse events (RR 3.50, 95% CI 3.26 to 3.75; 66 studies, 38,368 participants; low-certainty evidence), and may result in an increased risk of urinary retention (RR 3.52, 95% CI 2.04 to 6.08; 17 studies, 7862 participants; low-certainty evidence). Taking anticholinergics may be more likely to lead to participants withdrawing from the studies due to adverse events (RR 1.37, 95% CI 1.21 to 1.56; 61 studies, 36,943 participants; low-certainty evidence). However, taking anticholinergics probably reduces the mean number of micturitions per 24-hour period compared to placebo (MD 0.85 lower, 95% CI 0.98 lower to 0.73 lower; 30 studies, 19,395 participants; moderate-certainty evidence).Authors' conclusions: The use of anticholinergic drugs by people with overactive bladder syndrome results in important but modest improvements in symptoms compared with placebo treatment. In addition, recent studies suggest that this is generally associated with only modest improvement in quality of life. Adverse effects were higher with all anticholinergics compared with placebo. Withdrawals due to adverse effects were also higher for all anticholinergics except tolterodine. It is not known whether any benefits of anticholinergics are sustained during long-term treatment or after treatment stops.