Vitamin D has immunosuppressive properties and is considered a therapeutic option, although there is controversy about the role of this vitamin in the pathogenesis of systemic lupus erythematosus (SLE). We aimed to determine the prevalence of vitamin D insufficiency and deficiency and their potential association with disease activity, damage accrual, SLE-related clinical manifestations, and cardiovascular risk factors in SLE patients. A cross-sectional study of 264 patients was conducted (89.4% females; mean age 46.7 ± 12.9 years). The SLE Disease Activity Index (SLEDAI-2 K) and the SDI Damage Index were used to assess disease activity and disease-related damage, respectively. The mean 25(OH)D value was 25.1 ± 13.0 ng/ml. Eleven patients (4.2%) had 25(OH)D <10 (deficiency) and 178 patients (70.6%) had 25(OH)D <30 (insufficiency). In the 25(OH)D deficiency group, SLEDAI was significantly higher than the insufficiency (p = 0.001) and normal groups (p < 0.001). Also, patients with vitamin D deficiency presented significantly higher SDI scores than patients with 25(OH)D insufficiency (p = 0.033) and 25(OH)D normal levels (p = 0.029). There is a high prevalence of both vitamin D deficiency and insufficiency in Caucasian SLE patients and this status was associated with higher SLEDAI and SDI scores, supporting the impact of vitamin D levels on disease activity and damage accrual in SLE patients. Longitudinal studies on the relationship between vitamin D status and disease activity and progression are therefore required.
Keywords: 25 OH vitamin D; damage index; disease activity; nephritis; serositis; systemic lupus erythematosus.