Serum vitamin D level is associated with disease severity and response to ursodeoxycholic acid in primary biliary cirrhosis.

BACKGROUND

Serum vitamin D levels are associated with bone complications in patients with primary biliary cirrhosis (PBC). Increasing evidence suggests a nonskeletal role of vitamin D in various autoimmune and liver diseases.

AIM: To investigate the clinical relevance of vitamin D levels in PBC, especially their association with the therapeutic effects of ursodeoxycholic acid (UDCA).

METHODS

Consecutive PBC patients were retrospectively reviewed. 25-hydroxyvitamin D [25(OH)D] levels were determined in frozen serum samples collected before initiation of UDCA treatment. Response to UDCA was evaluated by Paris-I and Barcelona criteria. Logistic regressions were performed to identify the treatment response-associated parameters.

RESULTS

Among 98 patients, the mean serum 25(OH)D concentration was 17.9 ± 7.6 ng/mL. 25(OH)D levels decreased with increasing histological stage (P = 0.029) and were negatively correlated with bilirubin and alkaline phosphatase levels. After 1 year of UDCA therapy, 31 patients failed to achieve complete response according to Paris-I criteria. The baseline 25(OH)D level was significantly lower in nonresponders (14.8 ± 6.4 vs. 19.3 ± 7.6 ng/mL, P = 0.005). Vitamin D deficiency at baseline was associated with an increased risk of incomplete response independent of advanced stages (OR = 3.93, 95% CI = 1.02-15.19, P = 0.047). Similar results were obtained when biochemical response was evaluated by Barcelona criteria. Furthermore, 25(OH)D levels were lower in patients who subsequently suffered death or liver transplantation (12.1 ± 4.6 vs. 18.4 ± 7.6 ng/mL, P = 0.023).

CONCLUSIONS

25(OH)D level is associated with biochemical and histological features in PBC. Pre-treatment vitamin D status is independently related to subsequent response to UDCA. Our results suggest that vitamin D status may have important clinical significance in PBC.