Background/Purpose:  Psoriatic arthritis (PsA) is an inflammatory arthritis that may progress rapidly and result in joint damage and disability. The aim of this study was to establish the frequency of raised inflammatory markers (ESR and CRP) in PsA and to investigate their association with disease activity and progression.

Methods: At the PsA Clinic patients are followed prospectively and are evaluated according to a standard protocol which includes a detailed clinical history, physical examination, laboratory and radiological assessments every 6 –12 months.ESR levels are recorded as normal or raised (15 mm/hour for male patients, 20 mm/hour for female patients) as well as CRP as normal or raised (0-3). X-rays are done every two years. Patients followed between 2006 and 2011 were included.

ESR and CRP were measured at baseline in all patients included in this study, and correlated with other disease features at baseline. Pearson correlation coefficient was used for correlations between the continuous variables. We also constructed univariate and multivariate models based on information at baseline to detect the variables that associate with disease activity and severity. The covariates were age at onset of PsA, sex, duration of PsA, use of biologics, infection and BMI.

Results:   A total of 253 patients with PsA (107 male and 146 female with mean duration of PsA 5.2±7.6 years) were included.ESR level ranged from 0 to 121 mm/hr at baseline. Mean ESR was 18.3±21.2 (median 11) and was elevated in 28.1%. CRP level ranged from 3 to 132 mg/l. Mean CRP was 14.3±20.7 (median 5) mg/l and was elevated in 54.9%.

 Correlation between ESR and CRP with the variables

The association between ESR and CRP and different variables

 Conclusion: Increased ESR was observed in 28.1% of PsA and was correlated with active and damaged joint count and PASI. Increased CRP was observed in 54.9% of PsA and was correlated with PASI. Inflammatory markers are associated with disease activity and progression.