Association of Higher Levels of High-Sensitivity C-Reactive Protein With Future Development of Psoriatic Arthritis in Psoriasis: A Prospective Cohort Study.

Objective: We aimed to assess whether high-sensitivity C-reactive protein (hsCRP) levels 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 observed from 2006 to 2019 were analyzed. During the follow up period, 57 patients developed PsA. The mean level of hsCRP was 3.1 ± 5.5 mg/L (hsCRP levels in patients with incident PsA, 5.4 ± 13.1 mg/L). Significantly higher levels of hsCRP at baseline were found in patients with arthralgia, obesity, and in women. Higher hsCRP levels were associated with future development of PsA in multivariable analyses (hazard ratio 1.04; 95% confidence interval 1.01-1.07; P = 0.007). Similar effect size was seen in men and women. No significant interaction was found between hsCRP and sex or BMI.

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