Global incidence and prevalence of autoimmune hepatitis, 1970-2022: a systematic review and meta-analysis

Background Autoimmune hepatitis (AIH) varies significantly in incidence and prevalence across countries and regions. We aimed to examine global, regional, and national trends in incidence and prevalence of AIH from 1970 to 2022.Methods We conducted a thorough search of the PubMed/MEDLINE, Embase, CINAHL, Google Scholar, and Cochrane databases from database inception to August 9, 2023, using the search term "autoimmune hepatitis" in combination with "incidence," "prevalence," or "trend." Only general population-based observational studies with larger samples sizes were considered for inclusion. Studies that recruited convenience samples, and those with fewer than 50 participants were excluded. Summary data were extracted from published reports. A random effects model was used and pooled estimates with 95% CI were used to calculate the incidence and prevalence of AIH. Heterogeneity was evaluated using the I-2 statistic. The study protocol was registered with PROSPERO, CRD42023430138. Findings A total of 37 eligible studies, encompassing more than 239 million participants and 55,839 patients with AIH from 18 countries across five continents, were included in the analysis. Global pooled incidence and prevalence of AIH were found to be 1.28 cases per 100,000 inhabitant-years (95% CI, 1.01-1.63, I-2 = 99<middle dot>51%; number of studies, 33; sample population, 220,673,674) and 15.65 cases per 100,000 inhabitants (95% CI, 13.42-18.24, I-2 = 99<middle dot>75%; number of studies, 26; sample population, 217,178,684), respectively. The incidence of AIH was greater in countries with high Human Development Index (>0.92), in North America and Oceania (compared with Asia), among females, adults (compared with children), and high latitude (>45 degrees). Similar patterns in AIH prevalence were observed. Pooled AIH prevalence increased gradually from 1970 to 2019 (1970-1999; 9.95 [4.77-15.13], I-2 = 95<middle dot>58% versus 2015-2022; 27.91 [24.86-30.96], I-2 = 99<middle dot>32%; cases per 100,000 inhabitants). The overall incidence and prevalence of AIH, as well as some subgroup analyses of the studies, displayed asymmetry in the funnel plots, suggesting potential evidence of publication bias.Interpretation AIH incidence and prevalence have increased significantly and exhibit substantial variation across regions worldwide. Further research is required to assess the incidence and prevalence of AIH, specifically in South America and Africa.