Diagnostic and prognostic value of synovial biopsy in adult undifferentiated peripheral inflammatory arthritis: a systematic review.

OBJECTIVE

Our aim was to systematically review the literature on the diagnostic and prognostic value of synovial biopsy in undifferentiated peripheral inflammatory arthritis (UPIA) as an evidence base for generating clinical practice recommendations. The results lead to multinational recommendations in the 3e Initiative in Rheumatology.

METHODS

We performed a systematic literature review according to the PICO strategy (Patients, Intervention, Comparator, and Outcome). Using a designed search strategy we ran literature searches 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. Articles fulfilling predefined inclusion criteria were reviewed, and quality appraisal was performed.

RESULTS

Six publications from a total of 3265 diagnostic and 3271 prognostic studies were included, of which 2 were review articles. Data pooling was impossible because of significant clinical and statistical heterogeneity. Three themes of outcome were identified: anti-citrullinated peptide antibody (ACPA) staining in synovium, immunohistochemistry (CD22, CD38, CD68), and vascular patterns. Prognostic and diagnostic value was poor for these themes, although diagnostic trends favoring a particular diagnosis were identified. In contrast to serological ACPA testing, ACPA staining was shown not to be specific for diagnosis of rheumatoid arthritis (RA). Synovial CD22 and CD38 positivity seem to differentiate between RA and non-RA, while synovial CD38 and CD68 positivity can differentiate among RA, spondyloarthritis (SpA), and other diagnoses. Vascular patterns in undifferentiated arthritis are insufficiently specific to differentiate between SpA and RA.

CONCLUSION

There is sparse evidence that synovial biopsy has diagnostic or prognostic value in patients with UPIA in clinical care. We urgently need systematic studies investigating the diagnostic and prognostic potential of synovial markers. A clear, broadly accepted, and unequivocal definition of undifferentiated arthritis is required as a starting point.