Subgroup and sensitivity analyses

Prespecified subgroup analyses were undertaken to explore potential sources of clinical heterogeneity. Subgroups were defined according to patient population (medical, surgical, or mixed), intervention duration, and whether oligosaccharides were included as a component of the intervention. Intervention duration was obtained from the methods section of each study or, when not explicitly reported, from the mean or median treatment duration presented in the results. When sufficient data were available, subgroup analyses were performed within the network meta-analytic framework.

Several sensitivity analyses were conducted to assess the robustness of the primary findings. These analyses comprised the exclusion of studies judged to be at high risk of bias using the RoB 2 tool, the exclusion of studies with fewer than 50 participants to assess the potential influence of small-study effects, and restricting the analysis to trials with a limited control group, defined as placebo or usual care clearly confirmed to be fiber-free. Subsequently, sensitivity analysis results were compared with those of the primary analysis to evaluate the consistency of the findings.