Vitamin D status in rheumatoid arthritis patients: relation to clinical manifestations, disease activity, quality of life and fibromyalgia syndrome.

AIM: To assess vitamin D levels in rheumatoid arthritis (RA) patients and to find their relation to clinical parameters, fibromyalgia syndrome (FMS), quality of life (QoL) and disease activity.

METHODS: The study included 63 RA patients and 62 controls. Clinical examination and laboratory investigations were performed. For patients, the Disease Activity Score (DAS-28), QoL index, Health Assessment Questionnaire II (HAQ II) and Modified Larsen score were calculated. 25-OH-vitamin D was measured in patients and controls.

RESULTS: The patients' mean age was 41.59 ± 9.69 years and disease duration 5.89 ± 3.67 years. The level of vitamin D in RA patients was significantly lower (23.11 ± 12.71 ng/mL) than that in the controls (32.59 ± 13.06 ng/mL) (P = 0.005) being deficient in 50.8%, insufficient in 23.8% and normal in 25.4%. The RA patients with FMS (n = 33) had significantly lower levels of vitamin D (19.08 ± 10.59 ng/mL) than those without (27.55 ± 13.51 ng/mL) (P = 0.008). The difference was significant on comparing those receiving hydroxychloroquine (17.39 ± 7.84 ng/mL) to those not (31.85 ± 13.85 ng/mL) (P < 0.001). Vitamin D significantly correlated with QoL index (r = 0.58, P < 0.001) and negatively with HAQ II (r = -0.36, P = 0.004) and BMI (r = -0.39, P = 0.001).

CONCLUSION: Special attention is required regarding vitamin D levels in RA patients with FMS and decreased QoL. Vitamin D should be corrected and supplementation considered among the RA management armamentarium.