Diagnostic and Predictive Value of Acute-phase Reactants in Adult Undifferentiated Peripheral Inflammatory Arthritis: A Systematic Review

Objective. To review the available literature on the diagnostic and predictive value of acute-phase reactants in adult undifferentiated peripheral inflammatory arthritis (UPIA) as an evidence base for generating multinational clinical practice recommendations in the 3e Initiative in Rheumatology. Methods. A systematic literature search was carried out using Medline, Embase, the Cochrane Library, and abstracts presented at the 2007 and 2008 meetings of the American College of Rheumatology and European League Against Rheumatism, searching for prognostic and diagnostic markers of acute-phase reactants in adult UPIA. Articles that fulfilled predefined inclusion criteria were systematically reviewed, and the quality was appraised. Likelihood ratios (LR), sensitivity, and specificity for diagnostic and prognostic outcomes were calculated. Results. A total of 18 publications out of 3699 identified references were included in the review. Only a small number of studies with significant heterogeneity, including different outcome measures and different cutoff values, were eligible for review, so pooling data was not possible. Overall, LR showed poor diagnostic and prognostic performance for most investigated acute-phase reactants. Available data showed some value for erythrocyte sedimentation rate in establishing a diagnosis in patients with undifferentiated arthritis; some prognostic and diagnostic value for C-reactive protein; some prognostic value for plasma viscosity in predicting persistence of arthritis; and some diagnostic value for sulfhydryl levels and matrix metalloproteinase-3 in establishing a diagnosis of rheumatoid arthritis. Conclusion. There is little published evidence concerning the diagnostic and predictive value of acute-phase reactants in patients with UPIA. Studies were heterogeneous, and "undifferentiated arthritis" was not well defined or was equivocally defined. The role of acute-phase reactants in diagnosing and predicting outcome in patients presenting with undifferentiated arthritis is limited. (J Rheumatol 2011;38 Suppl 87:15-19; doi:10.3899/jrheum.101069)