Abstract
BACKGROUND: Metabolic bariatric surgery (MBS) quality registries monitor various outcomes, enabling the assessment of hospital performance in comparison with national benchmarks. However, if there is considerable between-surgeon outcome variation, surgeon-level feedback may be better suited. The aim of this study was to assess the extent to which patient-, surgeon-, and hospital-level factors contribute to the variation in outcomes after MBS. METHODS: All primary procedures registered in the Dutch MBS quality registry between 1 January 2020 and 31 December 2023 were included. Outcomes included severe postoperative complications, reoperation, prolonged length of stay (LOS), readmission, textbook outcome, and achieving ≥25% total weight loss within 1 year. Multilevel logistic regression models were built for each outcome, including all available patient characteristics, operating surgeon, and hospital, to determine the variance explained by patient-, surgeon-, and hospital-level factors. RESULTS: In total, 30 610 patients were included, operated on by 144 surgeons in 19 hospitals. Hospital-level factors contributed most to the explained variance for all outcomes, ranging from 59.6% for reoperation to 90.3% for prolonged LOS. Surgeon-level factors explained less variance, ranging from 3.2% for prolonged LOS to 28.2% for reoperation. Patient characteristics explained the least, ranging from 4.4% for textbook outcome to 13.1% for severe postoperative complications. CONCLUSION: Variation in outcomes is mostly explained by hospital factors, rather than surgeon factors, supporting hospital-based performance feedback. The results suggest that the pre- and postoperative trajectory and perioperative care may affect MBS outcomes more than patient characteristics or surgical team performance.