Abstract 12 — Prevalence and Risk Factors of Non-Alcoholic Fatty Liver Disease in Patients with Rheumatoid Arthritis: A Nationwide Population-Based Study

Background

Rheumatoid arthritis (RA) is a debilitating and financially burdensome disease because of frequent presence of comorbidities including metabolic and cardiovascular abnormalities. Growing evidence suggests a link between RA and nonalcoholic fatty liver disease (NAFLD). We aimed to determine the prevalence and explore the risk factors of developing NAFLD in RA population.

Methods

This population-based, cross-sectional study utilized data on US adults aged $\ge$20 years old from the National Health and Nutrition Examination Survey (NHANES) 2017-2018, a representative sample of the general US population. Diagnosis of RA was derived from questionnaire data. NAFLD was defined by controlled attenuation parameter (CAP) scores of $\ge$278 dB/m using vibration controlled transient elastography (VCTE) in the absence of other liver disease. Weighted multiple regression analysis was further performed to assess the independent risk factors.

Results

Of 2,848 people included in this study, 224 of them had self-reported RA. The prevalence of NAFLD in the overall sample was 41%, with a numerically higher prevalence in RA patients than those without arthritis (47% vs. 40%, p=0.30). Compared to those without NAFLD, RA patients with concomitant NAFLD had more prevalent metabolic comorbidities including obese (75% vs. 32%, p=0.006), central obesity (100% vs. 71%, p=0.008), diabetes (39% vs. 14%, p=0.003) and hyperlipidemia (88% vs. 76%, p=0.042). Regarding laboratory findings, RA patients with NAFLD exhibited higher levels of triglyceride (188 mg/dL vs. 131 mg/dL, p=0.010), fasting plasma glucose (131 mg/dL vs. 109 mg/dL, p=0.010) and HbA1c (5.77% vs. 6.41%, p=0.002). Meanwhile, elevated levels of liver enzymes (ALT: 29 U/L vs. 19 U/L, p=0.015; AST: 25 U/L vs. 19 U/L, p=0.007) and inflammatory indicator CRP (5.1 mg/dL vs. 3.4 mg/dL, p<0.001]) were more frequently reported in RA patients with NAFLD as compared with those without. Further, weighted multivariate logistic regression analysis showed that the presence of central obesity (adjusted OR=1.56 [95% CI 1.16-2.11], p=0.008) and diabetes (adjusted OR=1.28 [95% CI 1.07-1.54], p=0.014) were significantly associated with prevalent NAFLD in patients with RA.

Conclusion

In this population-based study, about one in two patients with RA had NAFLD, which is higher than its overall prevalence among general population. Central obesity and diabetes are predisposing factors for NAFLD in RA. Our results highlight the importance of active NAFLD screening in RA population, especially for high-risk subsets.