S1188 NAFLD Prevalence in BMI Subclass and Outcomes in 2019

Abstract

Introduction: NAFLD has been historically associated with obesity but was recently found to have an association with lean individuals as well. We thereby conducted a nationwide study to identify the prevalence of NAFLD in different BMI categories and their association with mortality. Methods: We queried the 2019 NIS database to identify all adult ( >18 years) patients with NAFLD using appropriate ICD-10-CM codes. We categorized BMI into category I (19.9 or less), category II (20-24.9), category III (25-29.9), category IV (30-34.9), category V (35-39.9), and category VI (> 40) using appropriate ICD-10-CM codes. An univariate screen followed by multivariate logistic regression was performed to adjust for potential hospital and patient level confounders. Stata 17.0 software was used to perform all statistical analyses. Results: A total of 532,485 NAFLD patients were identified which corresponds to 1.5% of the total US hospitalizations in the year 2019. Of which, 7,964 (1.5%) were category I, 7,530 (1.4%) were category II, 13,450 (2.5%) were category III, 36,650 (6.8%) were category IV, 42,715 (8%) were category V, and 94,425 (17.7%) were category VI. On multivariate analysis, we found that category I NAFLD patients had increased odds of mortality compared to other BMI subgroups [OR 1.71 (1.3-2.2); p< 0.001]. Conclusion: Obesity has been linked with the development of NAFLD. As expected, our study demonstrated an increasing prevalence of NAFLD with higher BMI. However, we found that 2.9% of NAFLD patients were not obese. This group of patients had been termed “lean NAFLD”. The hypothesis for lean NAFLD is poorly understood with theories including higher bile production and genetic variations. Interestingly, we found that category I NAFLD patients had higher odds of mortality compared to other BMI groups. These findings could be a result of lean individuals suffering chronic medical conditions or certain malignancies and is beyond the scope of our study. Further studies regarding etiologies for lean NAFLD might bring clarity to this subject.