Weight-loss thresholds after bariatric surgery and cardiovascular outcomes: more is better

Whether the extent of weight loss (WL) modulates bariatric surgery (BS) cardiovascular benefits has scarcely been assessed. Several WL thresholds have been commonly used to classify BS patients as good or poor responders without a proven clinical relevance. We examined the relationship between the magnitude of WL after BS and post-surgery major adverse cardiovascular-event (MACE) incidence. We also compared the performance of three different insufficient weight-loss (IWL) criteria for their association with MACE.

All individuals who underwent a primary Roux-en Y gastric bypass (RYGB) or sleeve gastrectomy (SG) in our institution at least six years before data analysis (12/2020) were included in the study. Data on MACE were available in 1638 of 1700 participants (96.4%). Proportional-hazard Cox analyses were performed to ascertain the association between MACE, WL, and the three IWL criteria. IWL was defined as: <50% excess weight loss (<50% EWL), <20% total body-weight loss (<20% TBWL), and -1 standard deviation of alterable weight-loss percentage (<1 SD% AWL).

During a mean follow-up of 10.2 ± 2.8 years, 86 participants experienced a first post-surgery MACE. Higher WL at one year (HR: 0.77 (95% CI: 0.61-0.98)) and 5 years (HR: 0.63 (95% CI: 0.42-0.92)) was related to a lower incidence of MACE. All short-term criteria for defining IWL were similarly associated with MACE, yet <1 SD% AWL identified more at-risk subjects. Five-year TBWL < 20% and 5-year <1 SD-AWL% were significantly associated with a higher risk for CV events. TBWL < 20% identified more subjects at risk.

The extent of WL is closely related to long-term MACE incidence. Patients who lost -1SD% AWL at one year or <20% TBWL at five years may be considered poor responders.