Background: Quality of metabolic bariatric surgery (MBS) care is often monitored by national registries using quality indicators (QIs), but data collection takes up considerable time and costs. QIs are mostly introduced merely based on expert opinion. Therefore, the study’s aim was to systematically evaluate whether all QIs from the Dutch Audit for Treatment of Obesity (DATO) are still relevant and useful to initiate quality improvement initiatives. Methods: Twenty-four QIs were evaluated using hospital data from 2022 to 2023. To test whether QIs measured the same quality of care aspect (parsimony and relevance), correlations of QI pairs were examined using Pearson correlation coefficients. Usefulness to identify improvement opportunities was considered limited when variance is ≤ 0.001 without any outliers identified, indicating that the QI could be retired. Actionability was assessed through line graphs of hospital performance over the years. Results: Eleven QIs were highly correlated to other QIs, particularly the follow-up and weight loss indicators at 2 and 4 years, and therefore lacked added value. The weight loss QIs showed minimal variance and were adjusted by increasing the threshold to achieving ≥ 25% total weight loss. Multiple QIs showed improving trends and thereby their actionability, most pronounced for postoperative complications. The final QI set measured three constructs with good validity: Cronbach’s alpha values 0.53 (safety), 0.70 (treatment effectiveness), and 0.43 (follow-up process). Conclusion: Through a systematic evaluation of the DATO QI set, a smaller set of 13 QIs was shown to capture the same relevant information to improve MBS care.

Introduction: Some patients undergoing metabolic bariatric surgery (MBS) may transfer to another hospital for subsequent procedures. Due to legal constraints imposed by privacy regulations on inter-hospital data sharing, limited research has examined the characteristics and outcomes of these patients. This study aimed to identify the frequency and factors associated with hospital transfer using a novel privacy-enhancing approach based on secure multi-party computation (MPC). Methods: All primary and secondary MBS procedures registered in the Dutch Audit for Treatment of Obesity between January 1, 2014, and December 31, 2022, were considered. MPC enabled privacy-preserving linkage of surgeries across different hospitals. Patients undergoing secondary surgery in the same or a different hospital were compared on patient and treatment characteristics and outcomes of primary MBS to investigate associations with hospital transfer. Results: Two thousand three hundred eighty-two patients with data on both primary and secondary MBS were identified. A minority (n = 275; 11.5%) underwent their second procedure elsewhere. At baseline, these patients on average were younger (37.9 vs. 42.5, p < 0.001), less often had hypertension or GERD, and had similar BMI (43.9 vs 43.9, p = 0.89) compared with those who stayed. At secondary surgery, the BMI of patients transferring hospitals on average was lower (39.0 vs. 43.0, p < 0.001), and the indication was more often recurrent weight gain (49.0% vs. 23.0%, p < 0.001). Conclusion: A minority of patients (1 in 9) transferred to a different hospital for secondary MBS. These patients were generally younger and had fewer obesity-related diseases. Although they presented with a lower BMI at the time of secondary surgery, they more frequently sought surgery for recurrent weight gain.