Association Between Psoriasis and Nonalcoholic Fatty Liver Disease Among Outpatient US Adults

Importance: Recent studies have shown an association between psoriasis and nonalcoholic fatty liver disease (NAFLD) in US inpatients, but the association is still unclear in the outpatient US population. Objective: To assess whether psoriasis is associated with NAFLD in outpatient US adults. Design, Setting, and Participants: This population-based cross-sectional study used data on US adults aged 20 to 59 years from the National Health and Nutrition Examination Survey (NHANES) 2003-2006 and 2009-2014 cycles. Data were analyzed from June to September 2021. Exposures: Self-reported psoriasis. Main Outcomes and Measures: The main outcome was NAFLD, defined as a US fatty liver index score greater than 30. Sampling weights were calculated according to NHANES guidelines. Results: Among 5672 adults included in this study (mean age, 38.9 years [95% CI, 38.4-39.3 years]; 2999 [51.1%] female), 148 (3.0%) had psoriasis and 5524 (97.0%) did not have psoriasis. A total of 1558 participants (26.8%) were classified as having NAFLD. Compared with participants without psoriasis, those with psoriasis had a higher prevalence of NAFLD (32.7% [52] vs 26.6% [1506]). In a multivariable logistic regression model adjusted for age, sex, race and ethnicity, educational level, family income, marital status, NHANES cycles, diabetes, metabolic syndrome, and smoking and alcohol drinking status, psoriasis was associated with NAFLD (odds ratio [OR], 1.67; 95% CI, 1.03-2.70). In subgroup analyses, psoriasis was associated with NAFLD among men (OR, 2.16; 95% CI, 1.10-4.24), among those aged 20 to 39 years (OR, 2.48; 95% CI, 1.09-5.67), and among those without diabetes (1.70; 95% CI, 1.05-2.76). An association between psoriasis and NAFLD was found in sensitivity analyses that excluded potential hepatotoxic medication use (OR, 1.72; 95% CI, 1.01-2.95) or non-Hispanic Black participants (OR, 1.76; 95% CI, 1.07-2.87), redefined NAFLD based on the hepatic steatosis index score (OR, 1.59; 95% CI, 1.01-2.50), and used inverse probability of treatment weighting (OR, 1.43; 95% CI, 1.09-1.86). Conclusions and Relevance: In this cross-sectional study, psoriasis was associated with NAFLD in the outpatient US adult population in adjusted models. This association may be important to consider in the context of clinicians prescribing potentially hepatotoxic medication for psoriasis management.