Short- and mid-term outcomes of SASI vs OAGB: a propensity score-matched study

BACKGROUND: This interim analysis evaluated the safety and efficacy of single anastomosis sleeve-ileal bypass (SASI) versus one-anastomosis gastric bypass (OAGB), and determined the optimal sample size for a prospective observational study using propensity score-matched (PSM) analysis. The short- and mid-term findings are reported herein. METHODS: By the mid-term analysis, 208 patients had completed at least six months of follow-up (108 SASI; 100 OAGB). Patients were matched 1:1 using propensity scores based on demographics, anthropometric measures and major comorbidities. Procedures were performed laparoscopically or robotically by experienced bariatric surgeons. Inverse probability of treatment weighting (IPTW) using average treatment effect among the treated weights was conducted as a sensitivity analysis. RESULTS: The planned sample size of 394 patients per group was not reached. After matching, no statistically significant differences in postoperative outcomes were detected between groups at 6, 12, or 18 months. Excess weight loss increased from 64.91% to 101.74% after OAGB and from 61.70% to 92.62% after SASI between short- and mid-term follow-up. At 18 months, all patients in both groups achieved medication-free blood glucose control. CONCLUSIONS: SASI appeared feasible, with no significant differences from OAGB in reported short- and mid-term outcomes. The study remains underpowered; longer follow-up and the planned sample size are needed.