Background and aims Vitamin D has important roles in the regulation of the immune system in Lupus. 71% of lupus patients experienced hypovitamin D in Indonesia,. This study was aimed to determine the effect of vitamin D supplementation on the degree of disease activity and degree of fatigue in SLE patients with hypovitamin D.

Methods Thirty nine SLE patients with hypovitamin D were studied, that randomised into two groups: 20 patients was given vitamin D and 19 patients received placebo for 3 months. Disease activity is determined by the SLEDAI scores and the degree of fatigue is determined by the FSS (Fatigue Severity Scale).

Results This study showed that supplementation of vitamin D 1200 IU per day increased 6:55±1:27 ng/cc of 25 (OH) D. The decreased of SLEDAI scores in the supplementation group were greater than the placebo group (6.45±3:07 vs 0.17±1.63), p=0.000. The decreased of Fatigue Severity Scale in the supplementation group also greater than the placebo group (2.27±0.73 vs 0.005±0.62.), p=0.000.

Conclusions Vitamin D supplementation plays a role on improving the activity of the disease (SLEDAI score) and the condition of fatigue (FSS) in SLE patients with hypovitamin D.