4.

Trial Sequential Analysis of operating time. DARIS = Pc 49.52%; RRR 20%; alpha 1.6%; beta 20 %; diversity 94%.

The cumulative Z‐curve (blue line) immediately crosses the conventional boundary line. This suggests that there was a difference in the operating time between laparoscopic‐endoscopic rendezvous and preoperative endoscopic sphincterotomy, with a low risk of random error. The horizontal green lines illustrate the conventional level of statistical significance, which was intersected from the first trial. With 313 patients randomised, we had sufficient evidence to accept that preoperative endoscopic sphincterotomy took less operative time than laparoscopic‐endoscopic rendezvous. We used Trial Sequential Analysis software to conduct the analysis and to generate the figure.

Legend: square symbol: Z‐score for single study; diamond symbol: trial sequential monitoring boundary for benefit score for single study.

Abbreviations: DARIS: diversity‐adjusted required information size; Pc: control group proportion observed in the trials; RRR = a relative risk reduction.