Changes in Vitamin D Levels in Patients With Systemic Lupus Erythematosus: Effects on Fatigue, Disease Activity, and Damage

Objective. To analyze whether changes in serum 25-hydroxyvitamin D (25[OH] D) levels affect activity, irreversible organ damage, and fatigue in systemic lupus erythematosus (SLE). Methods. We performed an observational study of 80 patients with SLE included in a previous cross-sectional study of 25(OH) D, reassessed 2 years later. Oral vitamin D-3 was recommended in those with low baseline 25(OH) D levels. The relationship between changes in 25(OH) D levels from baseline and changes in fatigue (measured by a 0-10 visual analog scale [VAS]), SLE activity (measured by the Systemic Lupus Erythematosus Disease Activity Index [SLEDAI]), and irreversible organ damage (measured by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index [SDI]) were analyzed. Results. Sixty patients took vitamin D-3. Mean 25(OH) D levels increased among all treated patients (P = 0.044), in those with baseline vitamin D levels <30 ng/ml (P < 0.001), and in those with baseline vitamin D levels < 10 ng/ml (P = 0.005). Fifty-seven patients (71%) still had 25(OH) D levels < 30 ng/ml and 5 (6%) had 25(OH) D levels < 10 ng/ml. Inverse significant correlations between 25(OH) D levels and the VAS (P = 0.001) and between changes in 25(OH) D levels and changes in the VAS in patients with baseline 25(OH) D levels < 30 ng/ml (P = 0.017) were found. No significant correlations were seen between the variation of the SLEDAI or SDI values and the variation in 25(OH) D levels (P = 0.87 and P = 0.63, respectively). Conclusion. Increasing 25(OH) D levels may have a beneficial effect on fatigue. Our results do not support any effects of increasing 25(OH) D levels on SLE severity, although they are limited by the insufficient 25(OH) D response to the recommended regimen of oral vitamin D-3 replacement.