Current data regarding the evaluation of systemic inflammation in patients with psoriatic arthritis (PsA) using acute-phase reactants, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), are limited, according to the results of an analysis published in The Journal of Rheumatology. Data show that there is only weak evidence to support normalization of these biomarkers in predicting good clinical outcomes.
Randomized controlled trials have mostly assessed CRP and ESR as a component of the American College of Rheumatology 20% improvement (ACR20) response criteria. In the current study, as part of the Group for Research and Assessment of Psoriasis and Psoriasis Arthritis–Outcome Measures in Rheumatology (GRAPPA-OMERACT) working group, the investigators conducted a systematic literature review on the performance of inflammatory biomarkers in patients with PsA.
The systematic search included peer-reviewed articles and abstracts from scientific meetings on randomized controlled trials and longitudinal, observational studies that evaluated systemic inflammation using acute-phase reactants in individuals with PsA. Construct validity, responsiveness, and predictive validity of the studies were assessed.
Of the 2764 articles that were retrieved, 71 were included in this systematic review. Of these, 28 reported on CRP or ESR separately. The remaining articles reported on CRP or ESR as part of the ACR response criteria. The studies in which OMERACT responsiveness was explored provided conflicting reports.
Overall, inflammatory biomarkers had construct validity for more active disease. Moreover, evidence suggested that an elevation in ESR levels was predictive of cardiovascular outcomes.
The researchers found that only weak evidence supported the normalization of inflammatory biomarkers in predicting good clinical outcomes and remission criteria in patients with PsA. The predictive value for cardiovascular outcomes, however, was generally good.
The investigators concluded that additional studies designed to assess systemic inflammation in patients with PsA using acute-phase reactants and other laboratory biomarkers are warranted to identify novel biomarkers that might be used to examine the inflammatory response in these individuals.
Elmamoun M, Leung YY, O’Sullivan D, et al. Using acute-phase reactants to inform the development of instruments for the updated psoriatic arthritis core outcome measurement set [published online November 1, 2018]. J Rheumatol. doi:10.3899/jrheum.180195