FABP4 Response After Roux-en-Y Gastric Bypass

Sixteen of the 28 participants had previously been enrolled in the control(probiotic‐only, non‐prebiotic) arm of a completed, registered randomized trial ofpre‐/probiotic supplementation after RYGB at the same institution (ClinicalTrials.govIdentifier: NCT03517345); these participants received no prebiotic intervention. Theremaining 12 participants underwent RYGB by the same surgeon during a comparable periodand were not enrolled in that trial. Blood samples from both subgroups had originallybeen collected and stored at ‐80°C as part of their respective prospective clinicalfollow‐up. FABP4 concentrations were subsequently measured in these banked, singlefreeze‐thaw samples using a commercial ELISA assay, blinded to patients' weight‐loss andinflammatory outcomes, and merged with the anthropometric and biochemical data collectedat the corresponding original visits. Because FABP4 assay and the present statisticalanalysis were performed after clinical follow‐up had already been completed for bothsubgroups, this study is registered retrospectively.