Introduction: Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of obesity and metabolic syndrome (Mets). MetS is a cluster of central obesity, dyslipidaemia, insulin resistance and hypertension. Bariatric surgery (BS) is an effective approach for weight loss and improvement in metabolic disorders. The long-term effects of BS on the major liver and renal outcomes in patients with NAFLD are uncertain. This study aimed to compare the association of BS with non-bariatric treatment (non-BS) and major adverse liver and renal outcomes. Methods: This population-based, multicenter, retrospective cohort study was conducted using the TriNetX platform. All adult patients( >18 years) diagnosed with NAFLD were identified after excluding other chronic liver diseases. We performed a 1:1 propensity score matching (PSM) for demographics, body mass index (BMI), and comorbidities. BS procedures included Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy. The main outcome of our study was to assess the major adverse liver events such as cirrhosis, liver cancers, and renal outcomes as the incidence of CKD after BS. Hazard ratios(HR) were calculated to compare the association of BS with the outcomes. Results: A total of 781,579 adult patients with NAFLD were identified. Among these, 9519 patients had a history of BS, and 772,060 participants did not. After PSM, BS and non-BS (9519 each) were well matched. For bariatric surgeries, 4378 (45.9%) patients had an RYGB. Among the BS cohort, a majority of participants were female and younger, White, and had a history of smoking. BS patients also had a higher mean BMI and were likely to have comorbidities such as diabetes, hypertension, cardiovascular diseases, chronic pulmonary diseases, and sleep apnea. In the adjusted analysis, for liver-related outcomes, the risks of cirrhosis (HR 0.80; 95%CI 0.63-0.98), hepatocellular carcinoma (HR 0.75; 95%CI 0.61-0.92), and malignant neoplasm of liver and intrahepatic bile duct (HR 0.80; 95%CI, 0.65-0.99), were significantly lower for BS patients. Similarly, BS patients had a lower risk of developing composite events of CKD than non-BS patients (HR 0.73; 95%CI 0.67-0.81). Likewise, the BS group was more protected against CKD for mild, moderate, ESRD and need for dialysis (Table). Conclusion: In this large, propensity score-matched multicenter study of patients with NAFLD, BS was associated with a lower risk of major incident liver and renal events than those who did not undergo surgery. Table 1. - Outcomes of bariatric surgery and non-bariatric surgery patients with NAFLD after propensity-matched analysis at 3 years of bariatric surgery Outcomes BS (n=9519), n(%) Non-BS (n=9519), n(%) Hazard Ratio€ (95% CI) Major liver-related outcomes Cirrhosis of liver 121(1.2) 154(1.6) 0.80(0.63-0.98) Hepatocellular carcinoma 151(1.5) 204(2.1) 0.75(0.61-0.92) Malignant neoplasm of liverand intrahepatic bileduct 159(1.6) 200(2.1) 0.80(0.65-0.99) Major renal related outcome CKD stage 1 and 2 174(1.8) 234(2.4) 0.75(0.61-0.91) CKD stage 3A and 3B 133(1.3) 179(1.8) 0.75(0.60-0.94) End stage renal disease 211(2.2) 271(2.8) 0.79(0.66-0.94) Composite endpoint of CKD* 823(8.6) 1118(11.7) 0.73(0.67-0.81) Need for dialysis 67(0.7) 94(0.9) 0.72(0.52-0.98) Abbreviations: BS, bariatric surgery; CI, confidence interval; CKD, chronic kidney disease.*Composite endpoint of CKD was defined as CKD progression from five stages (stages 1-5).€Adjusted for age, sex, ethnicity, race, smoking, hypertension, diabetes, hyperlipidemia, chronic respiratory diseases, chronic renal disease, and other comorbidities.