Patients with a newly recorded diagnosis of hidradenitis suppurativa (HS) have increased risks for developing inflammatory arthritis, including ankylosing spondylitis (AS), psoriatic arthritis (PsA), and rheumatoid arthritis (RA), according to study results presented at the American Academy of Dermatology’s Virtual Meeting Experience (AAD VMX) 2020, held online from June 12 to 14, 2020.
To evaluate and compare the risk for inflammatory arthritis in patients with vs without HS, researchers collected data from patients having commercial insurance in the United States, from January 1, 2003 to January 1, 2017. The study cohort included patients with newly diagnosed HS who were propensity score-matched 1:1 with control participants without HS with similar risk profiles. All participants were followed until 1 of the events, including primary outcome, death, disenrollment, or end of datastream, occurred. The main outcome of the study was a new diagnosis of inflammatory arthritis, including AS, PsA, other spondyloarthritis (SpA), or RA. Researchers conducted all statistical analyses using a validated version of the Aetion Evidence Platform.
Researchers identified 70,697 patients with HS (mean age, 36.54±14.65 years; 78.0% women) and 141,411 without HS (mean age, 38.29±21.12 years; 52.0% women) after 2:1 risk set sampling and before propensity score matching. Researchers also noted that patients did not have a range of chronic inflammatory and autoimmune conditions before cohort entry. Median follow-up for patients with and without HS was 527 and 539 days, respectively.
After propensity score matching, results showed that age, sex, healthcare utilization, and comorbidities were similar between both groups. Patients with vs without HS (n=60,872 for both) had a 65%, 44%, and 16% increased risk for AS, PsA, and RA, respectively (incidence rates, 0.6 vs 0.4, 0.8 vs 0.6, and 4.5 vs 3.9 per 1000 person-years; hazard ratios [HRs; 95% CI], 1.65 [1.15-2.35], 1.44 [1.08-1.93], and 1.16 [1.03-1.31], respectively). Researchers did not observe any association of HS with other SpA (HR, 1.02; 95% CI, 0.89-1.93), including reactive arthropathy, spinal enthesopathy, sacroiliitis, or unspecific inflammatory spondylopathies.
Researchers concluded, “Given the high burden of disease associated with both HS and arthritis, physicians treating patients with HS should be aware of symptoms suggestive of inflammatory arthritis (ie, morning stiffness, joint pain or swelling).”
Schneeweiss MC, Kim SC, Schneeweiss S, Rosmarin D, Merola JF. Hidradenitis suppurativa and the risk of inflammatory arthritis: a population-based follow-up study. Presented at: AAD VMX 2020; June 12-14, 2020. Poster 14344.