Methods: The Systemic Lupus International Collaborating Clinics (SLICC) enrolled patients recently diagnosed with SLE (<15 months) from 33 centres across 11 countries from 2000. Clinical, laboratory and therapeutic data were collected. Vitamin D level was defined according to tertiles based on distribution across this cohort, which were set at T1 (10–36 nmol/l), T2 (37–60 nmol/l) and T3 (61–174 nmol/l). MetS was defined according to the 2009 consensus statement from the International Diabetes Federation. Insulin resistance was determined using the HOMA-IR model. Linear and logistic regressions were used to assess the association of variables with vitamin D levels.
Results: Of the 1847 patients, 1163 (63%) had vitamin D measured and 398 (34.2%) subjects were in the lowest 25(OH)D tertile. MetS was present in 286 of 860 (33%) patients whose status could be determined. Patients with lower 25(OH)D were more likely to have MetS and higher HOMA-IR. The MetS components, hypertension, hypertriglyceridemia and decreased high-density lipoprotein (HDL) were all significantly associated with lower 25(OH)D. Increased average glucocorticoid exposure was associated with higher insulin resistance.
Conclusions: MetS and insulin resistance are associated with lower vitamin D in patients with SLE. Further studies could determine whether vitamin D repletion confers better control of these cardiovascular risk factors and improve long-term outcomes in SLE.
- Pharmacology (medical)