ODP008 Nonalcoholic Fatty Liver Disease (NAFLD) Impacts Weight Loss after Bariatric Surgery

BACKGROUND: Gastric bypass (GB) and sleeve gastrectomy (SG) remain the most effective intervention for weight loss in obesity. Our previous data showed a significant effect of preexisting diabetes on weight loss over 5 years. Since nonalcoholic fatty liver disease (NAFLD) is implicated as a precursor to clinical diabetes in obesity, we sought to determine if preexisting NAFLD modified weight loss outcomes. METHODS: 714 patients [79. 0% females, median age: 45 (37-53)] undergoing bariatric surgery were followed for 5 years. Clinically significant NAFLD at baseline was defined with a composite definition, combining the presence diagnosis on the medical record, definitive evidence for fat on imaging studies, presence of biopsy proving NAFLD, and/or elevation of liver function tests without another explanation. To screen for the presence of NAFLD, a natural language-processing tool EMERSE was utilized, and results were verified manually. Presence of diabetes, hypertension, and dyslipidemia were also defined using a combination of diagnostic codes, natural language processing and manual verification. Weight loss was tracked during annual visits and calculated using baseline weight and BMI. Total percent weight loss from baseline (%TWL) was also calculated. RESULTS: Of the 714 patients, 380 underwent GB [80.3% females, age 45 (35-53), median BMI 46.4 (41.6-51.9)] and 334 underwent SG [77.5% females, age 46 (39-54), BMI 49.7 (43.7-54.1)]. Overall, 31. 0% patients had clinically significant NAFLD at baseline, while the prevalence of diabetes, hypertension and dyslipidemia were 36. 0%, 54.9%, and 29.4% respectively. %TWL was impacted significantly by NAFLD in the GB group, as individuals without NAFLD lost medians of32.30 (26. 07-37.35), 32.33 (25. 04-39.21),31.12 (21.89-37.64), 26.40 (19.96-36.20), and 25.86 (18.16-34.79)%TWL versus29.63 (24.14-35.28),27.88 (21.44-35.11),24.15 (18.80-34.42),22. 09 (17. 03-30. 07), and21. 06 (14.92-30.25)%TWL compared to those with NAFLD by years1, 2, 3, 4, and 5 (p=0. 014,0. 002,0. 001,0. 002, and 0. 008). Among the SG group, differences in %TWL in NAFLD and non-NAFLD groupswere also significant, but only during year 1 and 2; non-NAFLD group had medians of25.73 (21.36-31.97) and24.55 (18.35-31.24) %TWL vs,22.48 (17.10-27.63) and22.28 (14.75-28.31)%TWL in NAFLD-group (p=<0. 001 and 0. 02). In a multivariable model for %TWL, preexisting NAFLD remained a highly significant covariate when adjusted for baseline BMI, age, gender, surgery type, time (year of follow up), time by surgery type, preexisting diabetes, baseline cholesterol and triglyceride levels (Beta; 95% CI: - 2.288; -3.938, -0.639 p=0. 0067). Of note, the only other significant covariate with regards to comorbidities was presence of baseline diabetes (Beta; 95% CI: -2.811; -4.602, -1. 021, p=0. 0022). CONCLUSIONS: Preexisting NAFLD impacts weight loss outcomes in patients undergoing bariatric surgery, more so in GB than SG. Mechanisms for the role of clinically significant NAFLD or diabetes in reducing weight loss potential after bariatric surgery require further studies. Presentation: No date and time listed