Effectiveness of nifedipine versus atosiban for tocolysis in preterm labour: a meta-analysis with an indirect comparison of randomised trials.

OBJECTIVE: To explore the effectiveness of nifedipine compared with atosiban for tocolysis in preterm labour. DESIGN: A systematic review of randomised controlled trials with meta-analysis using adjusted indirect comparison. POPULATION: Six hundred and seventy-nine women recruited in nine randomised trials evaluating the effectiveness of nifedipine versus beta-agonists, and 852 women recruited in four trials of atosiban versus beta-agonists. There were no trials comparing nifedipine directly with atosiban. METHODS: We performed meta-analysis with a technique involving an adjusted indirect comparison between nifedipine and atosiban using beta-agonists as the common comparator. This approach preserves the benefit accrued by randomisation in the original comparisons. MAIN OUTCOME MEASURES: Reduction in neonatal respiratory distress syndrome and delay in delivery by 48 hours. RESULTS: Nifedipine tocolysis was associated with a significant reduction in respiratory distress syndrome compared with atosiban (OR 0.55, 95% CI 0.32-0.97). It also increased the number of women whose delivery was delayed by 48 hours (OR 1.20, 95% CI 0.73-1.95), although this result was not statistically significant. CONCLUSIONS: When indirectly compared with atosiban, nifedipine tocolysis is more effective. In the absence of a direct comparison, our analysis provides a way to explore the potential benefits of nifedipine versus atosiban.