Abstract: Objective The aim of this study was to investigate serum vitamin D deficiency in patients with autoimmune hepatitis (AIH). Methods A total of 74 patients with AIH were admitted to our hospital between January 2015 and November 2020, and all patients went liver biopsies. Serum 25-hydroxyvitamin D levels were detected. Severe vitamin D deficiency was defined as serum 25-hydroxyvitamin D level <25 nmol/L, life support D deficiency (deficiency) was defined as serum 25-hydroxyvitamin D level between 25nmol/L and 75nmol/L, and normal serum vitamin D level as >75nmol/L. Results Out of the 74 patients with AIH, severe vitamin D deficiency, deficiency and normal vitamin D levels were found in 20 cases, 28 cases and 26 cases; the age when diagnosed in patients with severe vitamin D deficiency was (34.2±14.8) year-old, significantly younger than [(40.2±11.4) year-old] in patients with vitamin D deficiency or [(47.2±10.8) year-old] in AIH patients with normal vitamin D levels (P<0.05), the percentage of males was 45.0%, significantly higher than 21.4% in deficiency patients or 11.5% in patients with normal vitamin D level (P<0.05), serum albumin level was (28.4±4.0) g/l, significantly lower than (32.0±3.8) g/l in patients with serum vitamin D deficiency or (38.3±3.7) g/l in patients with normal serum vitamin D level (P<0.05), the percentage of liver cirrhosis was 40.0%, which was significantly higher than (21.4%) in patients with serum vitamin D deficiency or (15.4%) in patients with normal serum vitamin D level (P < 0.05), the complete response to immunosuppressive therapy was 30.0%, which was significantly lower than 46.4% in patients with serum vitamin D deficiency or 73.1% in patients with normal serum vitamin D level (P < 0.05), the incidence of liver related events was 65.0%, which was significantly higher than 39.3% in patients with serum vitamin D deficiency or 19.2% in patients with normal serum vitamin D level (P<0.05), and there were significant differences as respect to ages at diagnosis, gender percentage, serum albumin levels, liver cirrhosis percentages and liver related events between patients with vitamin D deficiency and those with normal vitamin D levels (P < 0.05); serum 25-hydroxyvitamin D level in patients with G4 hepatic histological activity was (19.3±6.2)nmol/L, significantly lower than (45.1±17.6)nmol/L in patients with G3, or (63.9±21.5)nmol/L in with G2, or (74.0±26.8)nmol/L in with G1 or (83.8±30.2)nmol/L in with G0 (all P<0.05】, and serum 25-hydroxyvitamin D level in patients with F4 liver fibrosis was(23.1±7.8)nmol/L, significantly lower than (42.9±18.8)nmol/L in patients with F3, or (68.0±20.4)nmol/L in with F2, or (82.7±28.6)nmol/L in with F1 or (94.4±33.0)nmol/L in with F0 (all P<0.05). Conclusion Severe vitamin D deficiency is found in patients with AIH, which might be related to a severe disease and poor response to immunosuppressive treatment, and warrants further clinical investigation.

Key words: Autoimmune hepatitis, Vitamin D deficiency, Clinical implication