Statistical Fragility in Minimally Invasive Colorectal Surgery Studies: A Review of Randomized Trials

The P value has been used as a statistical tool in randomized controlled trials (RCTs) to establish significance but does not provide information on the robustness of a study when used alone. The fragility index (FI) provides a supplemental approach for demonstrating robustness in RCTs that report dichotomous outcomes. This study aims to determine the statistical fragility of RCTs that compare minimally invasive techniques with open techniques in managing benign and malignant colorectal diseases. Dichotomous outcomes of minimally invasive surgery versus open surgery in RCTs from 2000 to 2023 were assessed. The overall FI and fragility quotient (FQ) of each study were calculated. Of the 1377 screened studies, 50 met the inclusion criteria. In total, 820 outcomes were recorded with 747 outcomes reported as not significant (P ≥ .05) and 73 as significant (P < .05). The overall FI for all studies including all outcomes was 5 (interquartile range [IQR] 4-7) with a FQ of 0.031 (IQR 0.014-0.062). Of the 50 RCTs, 6 (12%) reported a loss to follow-up that was greater than the overall FI of 5. As RCTs are judged increasingly beyond just the P value, practicing colorectal surgeons will benefit from using and interpreting the FI, FQ, and the P value of studies both in analyzing future RCTs and in determining whether or not to make a change in their clinical practice if there is an efficiently true discovery.