Effect of vitamin D treatment in ANCA-associated vasculitis: results from an exploratory perspective, pragmatic,...

Vitamin D deficiency has been linked with several autoimmune diseases. Data are limited in anti-neutrophil cytoplasm autoantibody (ANCA)-associated vasculitis (AAV), and it is unknown whether vitamin D could have a therapeutic role in AAV.

The prospective, pragmatic, non-randomised exploratory PRAVDA study with ITT and pre-protocol analyses aimed to enrol >100 patients with AAV at the Vasculitis Clinic (Toronto, Canada) from January to July 2021. 25-hydroxyvitamin D [25(OH)D] was measured at baseline by ELISA. Patients with low 25(OH)D (<75 nmol/L at baseline) were asked to increase vitamin D supplementation by 1000 IU/day (to a maximum 2000 IU/day). 25(OH)D was measured again at month 12. The primary endpoint was 12-month disease relapse. Secondary analyses included correlations between vitamin D status and disease-specific clinical features.

The study included 101 patients, 41 (40.6%) of whom had low baseline vitamin D levels and were asked to increase vitamin D3 intake. Of these patients, 32 had vitamin D level reassessed at month 12; 62.5% (20/32) had achieved normal levels. Relapse rates at month 12 were similar between patients with low (n=3/41; 7.3%) and normal (n=6/60; 10%; p=0.64) baseline vitamin D levels. However, no relapses were observed in patients who corrected baseline vitamin D deficiency.

These findings can help designing larger studies on vitamin D supplementation in AAV patients, focusing mostly on those vitamin D deficient at baseline.