Fig. 10

Trial sequential analysis of 8 trials comparing NOM vs. OM for postoperative complications. The cumulative Z-curve did not cross both the conventional boundary and the trial sequential monitoring boundary but crossed the required information size, suggesting that there are no significant differences in terms of complications and further trials difficulty will change this conclusion. A diversity adjusted required information size of 787 patients was calculated using an alpha = 0.05 (two sided) and a beta = 0.20 (power 80%), and empirical estimation from TSA software