Low levels of vitamin D were associated with higher disease activity in patients with systemic lupus erythematosus in an Australian cohort, according to recently published research.
Researchers prospectively studied 119 patients with systemic lupus erythematosus (SLE) under treatment at the Monash Medical Centre Lupus Clinic in Melbourne. One hundred patients were female (77.5%), 56.3% were white, 37.8% were Asian, 1.7% were of another race and racial background was unknown in 4.2% of patients. Patients’ mean age was 42.2 years, and mean disease duration was 8.7 years. All patients were treated with hydroxychloroquine, 58.8% were treated with glucocorticoids, 33.6% were treated with immunosuppressants, and 14.2% were treated with prednisolone.
Patients included in the study had at least one serum vitamin D measurement concurrently with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), anti-double-stranded DNA (dsDNA) antibodies, and measures of renal function and complement levels. Bone density of the femoral neck and lumbar spine using dual-energy X-ray absorptiometry within 12 months of vitamin D tests was also recorded.
At baseline, 33 patients (27.7%) were deficient in serum vitamin D and 53 (44.5%) were using vitamin D supplementation. A weak, but significant, inverse correlation was seen between levels of vitamin D and ESR, but no association was seen with CRP or bone density measurements.
Multiple linear regression analysis revealed that baseline vitamin D was significantly inversely correlated with the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K), as well as with supplementation of vitamin D. No association was seen with glucocorticoid treatment, according to the researchers.
During 12 months of follow-up, a median change of 25 nmol/L in vitamin D levels was seen, and SLEDAI-2K decreased by 2 units; however, this correlation was not considered statistically significant, according to the researchers.
At follow-up, 43 of 119 patients had low vitamin D and 26 of 119 patients had high disease activity. A weak association was seen with prior low vitamin D levels and higher disease activity or SLEDAI of 10 or greater, but adjustments for supplementation and use of glucocorticoids or immunosuppressive drugs eliminated the association. This suggests treatment of SLE may modify the activity between disease activity and serum levels of vitamin D, according to the researchers. - by Shirley Pulawski
Disclosure: The researchers report no relevant financial disclosures.