High Prevalence of Metabolic Syndrome and of Insulin Resistance in Psoriatic Arthritis Is Associated with the Severity of Underlying Disease

Objective. To investigate the prevalence of metabolic syndrome (MetS) and of insulin resistance (ER) in an ethnically homogeneous cohort of established psoriatic arthritis (PsA), and to identify clinical associations of MetS and ER in patients with PsA. Methods. A cohort of 283 patients with PsA all meeting ClASsification for Psoriatic ARthritis (CASPAR) criteria was included. All underwent detailed skin and rheumatologic assessments, along with cardiovascular risk factor evaluation. IR was defined as an elevated homeostasis model assessment HOMA-IR) value of > 2.5. Severe PsA was defined as the presence of 1 or more of the PsA-related radiographic damage features (peripheral joint erosions, osteolysis, sacroiliitis), and PsA requiring tumor necrosis factor inhibitor therapy. Results. The demographic and clinical characteristics of the cohort were mean age 54.6 +/- 12 years, 52% female, mean PsA duration 19 +/- 9 years. MetS was present in 44% of the studied patients (n = 283). On multiple regression analysis, a significant association of MetS was noted with more severe PsA (OR 4.47, p < 0.001). higher smoking pack-years (OR 1.03, p = 0.02), and worse EQ-5D scores (OR 1.28, p = 0.02). Data on ER were available for 263 patients, and among them, the mean HOMA-IR was 1.43 +/- 1.09. Forty-one patients (16%) had IR. On multiple regression analysis, a significant association of IR was noted with more severe PsA (OR 3.49, p = 0.03), later psoriasis age of onset (OR 1.07, p = 0.001), and higher body mass index (OR 1.22, p < 0.001). Conclusion. Among patients with PsA, MetS and IR are highly prevalent, and are independently associated with the severity of underlying PsA.