Five-year Outcomes After Single-Anastomosis Duodeno-Ileal Bypass (SADI) vs. Biliopancreatic Diversion with Duodenal Switch (BPD/DS): A Randomized Clinical Trial

Abstract

Background: Single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI) was introduced as a simplified modification of biliopancreatic diversion with duodenal switch (BPD/DS), aiming to maintain metabolic efficacy while shortening operating time and minimizing complications, including long-term nutritional deficiencies.

Methods: This single-center randomized trial enrolled adults with a body mass index > 45 kg/m² to either SADI or BPD/DS. The primary efficacy endpoint was 5-year percentage total weight loss (%TWL), and the primary safety endpoint was time to first unplanned reoperation within 5 years. Analyses were conducted in the treated population (n = 56; SADI n = 29, BPD/DS n = 27). The protocol was approved by the Regional Ethics Committee (Uppsala, Sweden) and registered at ClinicalTrials.gov (NCT03938571).

Results: Five-year weight data were available for 47 participants (SADI 24/29; BPD/DS 23/27). Observed mean %TWL was 34.3% after SADI and 36.7% after BPD/DS; the adjusted between-group difference in %TWL (SADI minus BPD/DS) was - 2.9% points (95% confidence interval [CI] - 8.7 to 2.9) with no statistically significant difference. 12 of 56 participants underwent at least one procedure-related reoperation (6/29 after SADI; 6/27 after BPD/DS). Internal herniation (n = 4) and malnutrition-related corrective surgery (n = 2) occurred only after BPD/DS. Vitamin D deficiency was more prevalent after BPD/DS than SADI (40.9% [9/22] vs. 12.5% [3/24]; p = 0.037), while a higher proportion of SADI patients had no deficiency in the combined panel of vitamin D, vitamin A, vitamin E, and zinc (44.4% [8/18] vs. 21.1% [4/19]). This composite difference was not statistically significant, and the small denominators and wide uncertainty preclude firm conclusions.

Conclusions: The trial did not provide evidence of a difference in 5-year weight loss; however, the wide confidence intervals preclude firm conclusions regarding comparative effectiveness. Overall reoperation frequency was similar, but BPD/DS was associated with a distinct pattern of reoperations, including internal herniation and malnutrition-related corrective surgery. Nutritional deficiencies were common after both procedures; vitamin D deficiency was more frequent after BPD/DS, and overall fat-soluble vitamin and trace element profiles appeared less favorable.