Prevalence and predictors of vitamin D insufficiency in supplemented and non-supplemented women with systemic lupus erythematosus in the Mediterranean region

It has been previously reported that vitamin D deficiency is more prevalent among SLE patients than in the general population. We sought to determine the prevalence of vitamin D insufficiency and deficiency and their related factors, its relationship to SLE symptoms and disease activity on a group of supplemented and non-supplemented female SLE patients from the Mediterranean region. We performed a cross-sectional study including female SLE patients who regularly attended the outpatient Lupus Unit at Parc de Salut Mar-IMAS in Barcelona, from January 2012 to May 2014. Collected data were sociodemographics, vitamin D supplementation, fatigue degree visual analog scale, pharmacological treatment, main SLE serological markers, indexes, scales and plasma levels of 25-hydroxyvitamin D. One hundred and two consecutive female SLE patients were included. Vitamin D overall insufficiency and deficiency were exhibited by 46 and 22.5 % of patients, respectively. Vitamin D insufficiency was found in 50 % of supplemented and 60 % of non-supplemented patients. Among non-supplemented female SLE patients, it was found that patients with vitamin D insufficiency showed more fatigue (p = 0.009) and received more oral corticosteroids (p = 0.02) than those with normal levels. Patients with vitamin D insufficiency (supplemented and non-supplemented) received more oral corticosteroids than those without insufficiency (p = 0.008). Vitamin D insufficiency is highly prevalent among female SLE patients, even in southern regions. Non-supplemented female SLE patients showed more fatigue and received more oral corticosteroids than those with normal levels of vitamin D. These data were not found in supplemented patients although having a high prevalence of vitamin D insufficiency (up to 50 %). Further studies with longer follow-up and larger population are needed to confirm our observations.