Constraint-induced movement therapy: trial sequential analysis applied to Cochrane collaboration systematic review results

Background: Trial sequential analysis (TSA) may establish when firm evidence about the efficacy of interventions is reached in a cumulative meta-analysis, combining a required information size with adjusted thresholds for conservative statistical significance. Our aim was to demonstrate TSA results on randomized controlled trials (RCTs) included in a Cochrane systematic review on the effectiveness of constraint-induced movement therapy (CIMT) for stroke patients. Methods: We extracted data on the functional independence measure (FIM) and the action research arm test (ARAT) from RCTs that compared CIMT versus other rehabilitative techniques. Mean differences (MD) were analyzed using a random-effects model. We calculated the information size and the cumulative Z-statistic, applying the O'Brien-Fleming monitoring boundaries. Results: We included data from 14 RCTs. In the conventional meta-analysis (seven trials, 233 patients), the effect of CIMT on FIM was reported as significant (MD 2.88, 95% CI 0.08 to 5.68; P = 0.04). The diversity-adjusted required information size was 142 patients, and the cumulative Z-score did not cross the trial sequential monitoring boundary for benefit (adjusted 95% CI -0.02 to 5.78). The effect of CIMT on ARAT (nine trials, 199 patients) was reported as significant (MD 7.78, 95% CI 1.19 to 14.37; P = 0.02). However, the diversity-adjusted required information size was 252 patients, and the Z-score did not cross the trial sequential monitoring boundary for benefit (adjusted 95% CI -0.06 to 15.62). Conclusions: Although conventional meta-analyses of CIMT reached statistical significance, their overall results remain inconclusive and might be spurious. Researchers should not be overconfident on CIMT efficacy based on the results of meta-analyses and derived recommendations.