Meta-Analysis of Once-Daily Generic Anticholinergic Medication for Overactive Bladder
Objective: To evaluate randomized clinical trials that compared the only once-daily medication for overactive bladder (OAB) management, oxybutynin extended release (ER), with other anticholinergic comparators.
Study Design: We performed a systematic review and meta-analysis of randomized clinical trials through the year 2010 that evaluated oxybutynin ER.
Methods: Studies published through 2010 were identified using searches of PubMed/MEDLINE with the search terms “urinary bladder,” “overactive/drug therapy,” “urinary incontinence,” “oxybutynin,” and “NOT administration, cutaneous.” Studies were limited to randomized clinical trials in English. A random-effects model was used to combine the studies and determine efficacy of oxybutynin ER compared with other drugs as the standardized mean difference (SMD). To aid clinical coherence, we converted this value to a difference in episodes of total incontinence, frequency, and urge incontinence. A fixed-effects model of primary outcomes was also applied as a sensitivity analysis.
Results: A total of 2090 subjects with OAB were included. Oxybutynin ER had statistically larger improvements than comparator drugs for episodes of total incontinence and frequency, with SMDs favoring oxybutynin ER of −0.11 (95% confidence interval [CI] −0.20, −0.01) and −0.14 (95% CI −0.27, −0.02), respectively. However, these gains were modest from a clinical perspective. Oxybutynin ER did not demonstrate statistical superiority in urinary urge incontinence episodes, with an SMD of 0.09 (95% CI −0.10, 0.28).
Conclusions: Oxybutynin ER efficacy is comparable to other anticholinergics used for OAB. These efficacy findings, the lower cost of this medication relative to patent-protected drugs, and once-daily formulation should be considered when developing formulary decisions for OAB management.
(Am J Pharm Benefits. 2011;3(5):e85-e92)
Study Design: We performed a systematic review and meta-analysis of randomized clinical trials through the year 2010 that evaluated oxybutynin ER.
Methods: Studies published through 2010 were identified using searches of PubMed/MEDLINE with the search terms “urinary bladder,” “overactive/drug therapy,” “urinary incontinence,” “oxybutynin,” and “NOT administration, cutaneous.” Studies were limited to randomized clinical trials in English. A random-effects model was used to combine the studies and determine efficacy of oxybutynin ER compared with other drugs as the standardized mean difference (SMD). To aid clinical coherence, we converted this value to a difference in episodes of total incontinence, frequency, and urge incontinence. A fixed-effects model of primary outcomes was also applied as a sensitivity analysis.
Results: A total of 2090 subjects with OAB were included. Oxybutynin ER had statistically larger improvements than comparator drugs for episodes of total incontinence and frequency, with SMDs favoring oxybutynin ER of −0.11 (95% confidence interval [CI] −0.20, −0.01) and −0.14 (95% CI −0.27, −0.02), respectively. However, these gains were modest from a clinical perspective. Oxybutynin ER did not demonstrate statistical superiority in urinary urge incontinence episodes, with an SMD of 0.09 (95% CI −0.10, 0.28).
Conclusions: Oxybutynin ER efficacy is comparable to other anticholinergics used for OAB. These efficacy findings, the lower cost of this medication relative to patent-protected drugs, and once-daily formulation should be considered when developing formulary decisions for OAB management.
(Am J Pharm Benefits. 2011;3(5):e85-e92)
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