Risk of non-alcoholic fatty liver disease in patients with chronic plaque psoriasis: an updated systematic review and meta-analysis of observational studies

Purpose Chronic plaque psoriasis is associated with the presence of non-alcoholic fatty liver disease (NAFLD), but the magnitude of this association remains currently uncertain. We aimed to investigate the magnitude of the association between psoriasis and the risk of prevalent and incident NAFLD, and to assess whether psoriasis severity and/or psoriatic arthritis are associated with a greater risk of NAFLD. Methods A systematic review and meta-analysis of observational studies evaluating the association between psoriasis and NAFLD, as diagnosed by imaging or International Classification of Diseases codes was performed. Literature search on PubMed, Scopus and Web of Science on May 3, 2021 was undertaken. Studies using liver biopsy were not available. For the meta-analysis, the random-effects modelling was adopted. Results We identified 15 observational (case-control and cross-sectional) studies for a total of 249,933 patients with psoriasis (49% with NAFLD) and 1,491,402 controls (36% with NAFLD). Psoriasis was associated with prevalent NAFLD (n = 11 studies; pooled random-effects odds ratio [OR] 1.96, 95% CI 1.70-2.26; I-2 = 97%, p < 0.01). Psoriatic patients with NAFLD had a higher mean psoriasis area and severity index (PASI) than their counterparts without NAFLD (n = 8 studies, pooled weighted mean difference: 3.93, 95% CI 2.01-5.84; I-2 = 88%, p < 0.01). The risk of NAFLD was marginally higher in patients with psoriatic arthritis than in those with psoriasis alone (n = 5 studies, pooled random-effects OR 1.83, 95% CI 0.98-3.43; I-2 = 64%, p = 0.03). Sensitivity analyses did not alter these findings. Funnel plot did not show any significant publication bias. A major limitation of the study was the high degree of heterogeneity across studies. Conclusion Psoriasis is associated with prevalent NAFLD and this risk parallels the severity of psoriasis.