Objective: When patients present with undifferentiated peripheral inflammatory arthritis (UPIA), early diagnosis and evaluation of prognostic factors are decisive steps for therapeutic success. We reviewed published evidence on the diagnostic and prognostic performance of autoantibodies and soluble biomarkers in UPIA.
Methods: We conducted a systematic literature search covering studies published until January 2009. Additionally, we screened conference abstracts presented at European League Against Rheumatism and American College of Rheumatology meetings in 2007 and 2008.
Results: We included 52 full-text articles and 12 abstracts. The association of anti-cyclic citrullinated peptide antibody (anti-CCP) and rheumatoid factor (RF) with diagnosis of rheumatoid arthritis at followup is compelling, supported by positive likelihood ratios (LR+) ranging between 1.2 and 20.5 for anti-CCP and 1.1 to 13.5 for RF. The same applies to radiographic outcome. For antikeratin antibodies (AKA) and antiperinuclear factor, existing evidence suggests diagnostic usefulness; AKA also showed prognostic value. Diagnostic and prognostic evidence for other autoantibodies and for bone and cartilage biomarkers was scarce, negative, or controversial.
Conclusion: Among serological tests, unanimous evidence of substantial diagnostic value exists only for anti-CCP and RF, but is scarce for other markers.