Higher levels of high-sensitivity CRP are associated with future development of Psoriatic Arthritis in Psoriasis: A prospective cohort study.

Objective: We aimed to assess whether high sensitivity c-reactive protein (hsCRP) could predict the development of psoriatic arthritis (PsA) in patients with psoriasis.

Methods: We analyzed data from a prospective cohort of patients with psoriasis without PsA at enrollment. Participants were assessed annually by a rheumatologist for signs and symptoms of PsA. Information on patient demographics, psoriasis features, medications and musculoskeletal symptoms was collected. hsCRP levels were measured in serum samples collected at baseline using standard commercial assays. The association between hsCRP levels and risk of development of PsA was assessed using multivariable Cox proportional hazards model adjusted for age, sex, psoriasis severity and duration, nail lesions, body mass index (BMI), fatigue, and medication use.

Results: A total of 589 patients with psoriasis followed from 2006 to 2019 were analyzed. 57 patients developed PsA during the follow up period. Mean level of hsCRP was 3.1±5.5 mg/L (hsCRP levels in incident PsA cases: 5.4±13.1). Significantly higher levels of hs-CRP at baseline were found in patients with arthralgia, obesity and in females. Higher hs-CRP levels were associated with future development of PsA in multivariable analysis (hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.01, 1.07, p=0.007). Similar effect size was seen in males and females. No significant interaction was found between hsCRP and sex or BMI.

Conclusion: Higher levels of systemic inflammation, as measured by hsCRP, are associated with future development of PsA.