Objectives To assess the vitamin D status in patients presenting inflammatory back pain suggesting of axial spondyloarthritis and to assess the relationship between vitamin D status and disease activity/severity; comorbidities at baseline and during the 2 years of follow up in an early axial spondyloarthritis (SpA)
Methods DESIR is a prospective, multi-center, observational study. 25OHvitD (vitD) was collected at baseline one frozen serum centrally at baseline (starting point for DESIR) with VitD deficiency defined as <20 ng/ml and severe deficiency less than 10 ng/ml. Clinical variables were collected at each 6 months interval visits during the 2 years follow-up whereas radiological and the cardiovascular risk factors were collected at baseline.
Results A total of 700 patients were analyzed. The mean vit D was 21.7±11.5 ng/ml; 51% of patients had vitD deficiency. After adjusting for season and ethnic group, vitD deficiency remained significantly associated with presence of radiological sacroiliitis (OR =1.51 [1.03-2.23], p=0.03), higher ASDAS score (OR =1.63 [1.07-2.48], p=0.02) and elevated BASDAI >40 (OR=1.46 [1.04-2.07], p=0.03). Such association was also found between vitD deficiency and the mean value of disease activity/severity during the two years follow-up. Otherwise, vitD deficiency was significantly associated with the presence of abdominal obesity (OR=1.65 [1.05-2.61], p=0.03), a low HDL (OR=1.71 [1.14 -2.55], p=0.01) and the presence of the metabolic syndrome (OR=2.20 [1.04- 4.64], p=0.03).
Conclusions Our findings regarding the prevalence of vitamin D deficiency, raises the question of the potential need of supplementation by vitamin D in SpA and its potential impact on disease activity, severity and cardiovascular comorbidities. However, these results have to be carefully interpreted. Further longitudinal studies are required to evaluate the interest of vitamin D supplementation on the long term outcome of the disease.
Acknowledgements This research was conducted while Ihsane Hmamouchi was an ARTICULUM Fellow.
Disclosure of Interest : None declared