Autoimmune Hepatitis and Vitamin D Deficiency: A Nationwide Perspective

ABSTRACT Background Vitamin D deficiency is linked to worse outcomes in patients with chronic liver diseases (CLD). However, data in patients with autoimmune hepatitis (AIH) remain limited. Aims We aimed to assess the impact of vitamin D deficiency on the outcomes of individuals with AIH. Methods This retrospective cohort study used the TriNetX research network to identify patients with AIH. Patients were matched using propensity score matching and stratified to sufficient vitamin D levels (e.g., 25 (OH) D3 ≥ 30 ng/mL), vitamin D insufficiency (25 (OH) D3: 20–29.9 ng/mL) and vitamin D deficiency (e.g., 25 (OH) D3 < 20 ng/mL). The primary outcome was the all‐cause mortality among adult patients with AIH. Secondary outcomes included decompensated liver cirrhosis, acute hepatic failure, liver transplantation (LT), all‐cause hospitalizations and all‐cause critical care admissions. Results A total of 1288 AIH patients with vitamin D deficiency were identified and propensity matched with 1288 patients with normal vitamin D levels. Patients with vitamin D deficiency had significantly increased odds for all‐cause mortality compared to those with normal levels (adjusted odds ratio (aOR) = 3.2, 95%CI: 2.3–4.48). Patients with vitamin D deficiency were at increased odds of all‐cause hospitalizations (aOR = 2.37, 95%CI: 1.97–2.84), critical care unit admissions (aOR = 2.8, 95%CI: 2.21–3.71), decompensated liver cirrhosis (aOR = 2.74, 95%CI: 2.13–3.54), acute hepatic failure (aOR = 3.11, 95%CI: 2.09–4.62) and LT (aOR = 3.47, 95%CI: 1.71–7.04), as compared to those with normal vitamin D levels. Conclusion This cohort study showed significantly increased odds for all‐cause mortality in AIH patients with vitamin D deficiency. Vitamin D deficiency in patients with AIH was associated with increased likelihood of hospitalisation, decompensated liver cirrhosis, acute liver failure and LT.