Hidradenitis suppurativa increases risk for inflammatory arthritis

There is an increased risk for developing inflammatory arthritis among patients with hidradenitis suppurativa, according to a population-based cohort study published in JAMA Dermatology.

“Hidradenitis suppurative (HS) has been associated with a high prevalence of spondylarthritis; however, the population-based risk of developing inflammatory arthritis remains unclear,” Maria C. Schneeweiss, MD, of the department of dermatology at Brigham and Women’s Hospital at Harvard Medical School, and colleagues wrote.

Researchers conducted this study to evaluate the risk for developing inflammatory arthritis among patients with HS compared with matched patients without HS. Patients diagnosed with HS were identified using longitudinal claims data. Patients who received a diagnosis of HS were included in the study. Patients with HS were defined as having one diagnosis from a dermatologist or three diagnosis from any health care professional.

The outcomes identified by researchers were ankylosing spondylitis, psoriatic arthritis, other spondylarthritis and rheumatoid arthritis.

A total of 70,697 patients with HS (mean age, 36.5 years) and 141,412 patients without HS were enrolled. After propensity score matching, patients with HS had an increased risk for developing ankylosing spondylitis (incidence rate, 0.6 vs. 0.36 per 1,000 person-years), psoriatic arthritis (incidence rate, 0.84 vs. 0.58 per 1,000 person-years) and rheumatoid arthritis (incidence rate, 4.54 vs. 3.86 per 1,000 person-years) compared with patients without HS.

“We observed increased risks of developing ankylosing spondylitis, psoriatic arthritis and rheumatoid arthritis among patients with HS compared with those without HS,” the researchers wrote.

Results showed that the incidence of arthritis was low with only between two and six additional cases per 10,000 patients with HS per 1.5 years.

“Further work is needed to elucidate the underlying potential shared pathogenesis of these disorders,” they wrote. – by Erin T. Welsh

Disclosures: Schneeweiss reports she is the principal investigator of investigator-initiated grants to the Brigham and Women’s Hospital from Bayer, Boehringer Ingelheim and Vertex and serves as a consultant to Aetion and WHISCON. Please see the study for all other authors’ relevant financial disclosures.