Background: Active vitamin D metabolite, 1, 25-dihydroxyvitamin D, has pleomorphic effects on both innate and acquired immunity. Sarcoid granuloma derived 1, 25-dihydroxyvitamin D leads to hypercalcemia, but the association of 1, 25-dihydroxyvitamin D with the clinical phenotype of the disease is currently unknown.
Objective: To determine the relationship between serum 1, 25-dihydroxyvitamin D levels and the degree of sarcoidosis disease chronicity.
Design: Serum 1, 25-dihydroxyvitamin D levels were measured and associated with sarcoidosis activity and phenotypes as assessed by Sarcoidosis Severity Score and Sarcoidosis Clinical Activity Classification respectively.
Results: Fifty nine patients were recruited with 44% having a sub-acute onset, and the chronic disease phenotype. There was no significant difference in serum 1, 25-dihydroxyvitamin D levels by chest radiograph stage (p = 0.092) nor did the levels correlate with the Sarcoidosis Severity Score (r = -0.16; p = 0.216). Serum 1, 25-dihydroxyvitamin D levels were associated with patients requiring repeated regimens of systemic immunosuppressive therapy or >1 year of therapy (SCAC Class 6). Increasing quartiles of serum 1, 25-dihydroxyvitamin D level was associated increased odds of the chronic phenotype (OR 1.82, 95% CI, 1.11, 2.99, p = 0.019). The majority (71%) of the patients with levels >51 pg/mL required chronic immunosuppressive therapy as defined by SCAC class 6.
Conclusions: In patients with sarcoidosis, elevated 1, 25-dihydroxyvitamin D levels are associated with chronic treatment needs.
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