People with psoriatic arthritis at greater risk of developing osteoarthritis

Patients with psoriatic arthritis (PsA) appear to have a higher risk of osteoarthritis (OA) than those with psoriasis alone and those in the general population, reports a study.

Using the United Kingdom Clinical Practice Research Datalink, the authors identified incident PsA patients aged 18–89 years at diagnosis between 1998 and 2014 to determine the risk of OA diagnosis in this population. All patients with PsA were matched 1:4 to the following cohorts: patients with psoriasis (and no PsA) and a general population (with no psoriasis or PsA).

Baseline OA prevalence for each cohort was calculated, as well as the incidence of OA and adjusted relative risks (RRs) using conditional Poisson regression.

A total of 6,783 patients with incident PsA were included in the analysis. The baseline OA prevalence ranged from 22.1 percent (95 percent confidence interval [CI], 21.1–23.1) in the PsA cohort to 12.6 percent (95 percent CI, 12.1–13.0) in the psoriasis alone cohort and 11.0 percent (95 percent CI, 10.6–11.3) in the general population.

After adjusting for body mass index, OA incidence was found to be significantly higher in the PsA cohort than in the psoriasis alone (adjusted RR, 1.68, 95 percent CI, 1.46–1.93) and general population cohorts (adjusted RR, 1.86, 95 percent CI, 1.62–2.14).

“Further work is needed to determine whether this reflects a true increase in OA risk or misdiagnosed PsA and the extent to which it can be explained by differences in the opportunity for OA diagnosis between cohorts,” the authors said.