PB1216 - The association between vitamin D and disease activity in adult patients with chronic primary immune thrombocytopenia

Background: Vitamin D deficiency is associated with several autoimmune diseases and increases the autoimmune response. For immune thrombocytopenia (ITP), vitamin D deficiency was found to be associated with disease activity in children, but has never been assessed in adults.

Aims: To evaluate the association between vitamin D levels and disease activity in adults with chronic primary ITP.

Methods: This is a single-center cross-sectional study, in which patients with a confirmed diagnosis of chronic primary ITP with current platelet counts of < 100x10^9/L or with a current treatment for chronic primary ITP were included. Serum 25-OH-vitamin D and platelet count were determined in patients using blood samples. Vitamin D deficiency was defined as serum 25-OH-vitamin D < 50nmol/L. High disease activity was defined as platelet counts < 30x10^9/L or current treatment for ITP. Logistic regression was used to assess the relation between vitamin D deficiency and disease activity.

Results: 57 patients (61% female, mean age 45 (range 17-82)) were included, of whom 23 (40%) had high disease activity and 28 (49%) had a vitamin D deficiency. 13 out of 28 (46%) patients with a vitamin D deficiency had high disease activity compared to 10 out of 29 (34%) in the patients without a vitamin D deficiency ( odds ratio 1,65 (95% CI 0,57-4,78; p=0,36)).

Conclusion(s): In this study, no significant association was found between vitamin D deficiency and disease activity in adult patients with chronic primary ITP.