Is vitamin D associated with disease activity in patients with axial or peripheral spondyloarthritis? A real-life study

Vitamin D plays important role in inflammatory rheumatic diseases, which in turn rose an interest for investigating association of its deficiency with disease activity. In this research we aimed to evaluate this matter in the context of spondyloarthritis (SpA), together with treatment modalities and bone density in people diagnosed with axial or peripheral SpA in real-life setting. In our study we enrolled 99 patients with diagnosis of SpA treated at the tertiary level rheumatology department. Serum 25(OH)D levels, treatment modality (NSAIR or DMARDs), disease activity, tobacco smoking habits, mineral density of bone, supplementation and seasonal variations were assessed. We used standardized questionnaires such as ASDAS-CRP, BASFI and joint count, among many others, to evaluate some of the mentioned parameters. Sixty-five percent of patients had vitamin D deficiency. We found marginaly higher activity of disease in subjects with low vitamin D. In cases of peripheral SpA, there was a significant association of higher number of swollen joints and lower vitamin D levels. Additionally, the significant correlation was seen between normal serum vitamin D and supplementation. In our real-life study of patients with SpA we found a significant percentage of vitamin D deficit, with a tendency of slightly higher disease activity in those patients.In order to clarify the impact of the vitamin on disease activity in SpA and the supplementation recommendations for patients with these conditions, the conduction of further studies is required.