SAN DIEGO – , results from a single-center cohort study showed.
“We had previously proved that vitamin D supplementation helped lupus activity,” lead study author Michelle Petri, MD, MPH, said in an interview in advance of the annual meeting of the American College of Rheumatology. “Now, we prove that it specifically helps renal activity as measured by the urine protein. By helping to reduce urine protein, it helps to prevent permanent renal damage and end-stage renal disease.”
Dr. Michelle Petri
The first measure of vitamin D typically occurred in late 2009 or 2010 for existing patients and at the first visit of new patients after that. The researchers categorized patients based on their first measure of vitamin D as less than 20 ng/mL or 20 ng/mL or higher. At the first visit when vitamin D was measured, 27.3% had levels of 25-hydroxyvitamin D less than 20 ng/mL. The mean age of patients was 47.3 years, 92% were female, 50% were white, and 41% were African American.
In the study, Dr. Petri and her associates used the Systemic Lupus International Collaborative Clinics/American College of Rheumatology Damage Index to calculate the risk of lifetime organ damage. After adjusting for age, gender, and ethnicity, low levels of vitamin D were significantly associated with increased risk of renal damage (RR, 1.66; P = .0206) and total organ damage (RR, 1.17; P = .0245), they found.
Skin damage was another concern, with an adjusted relative risk of 1.22, though it was not statistically significant (P = .3561). The investigators observed no association between low vitamin D and musculoskeletal damage, including osteoporotic fractures.
“There is a lot of interest in lupus right now, due to [singer Selena] Gomez’s kidney transplant for lupus nephritis,” said Dr. Petri, who also directs the Johns Hopkins Lupus Center. “So, I think there is interest in how to prevent the need for kidney transplant. Vitamin D helps kidney lupus – and we only need to achieve a level of 40 ng/mL, [which is] safe and easy to do.” She acknowledged the study’s single-center design as a limitation but underscored its large sample size as a strength.
The Hopkins Lupus Cohort is funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Dr. Petri disclosed having received research support from Anthera, GlaxoSmithKline, EMD Serono, Eli Lilly, Bristol-Myers Squibb, Amgen, United Rheumatology, Global Academy, and Exagen.