Relationship between disease activity indices and their individual components and radiographic progression in RA: a systematic literature review.

Objective: The aim of this study was to investigate the relationship between different disease activity indices (DAIs) and their individual components and radiographic progression in patients with RA.

Methods: A systematic literature review until July 2013 was performed by two independent reviewers using the Medline and Embase databases. Longitudinal studies assessing the relationship between DAIs and single instruments and radiographic progression were included. The results were grouped based on the means of measurement (baseline vs time integrated) and analysis (univariable or multivariable).

Results: Fifty-seven studies from 1232 hits were included. All published studies that assessed the relationship between any time-integrated DAI including joint count and radiographic progression reached a statistically significant association. Among the single instruments, only swollen joint count and ESR were associated with radiographic progression, while no significant association was found for tender joint count. Data with respect to CRP are conflicting. Data on patient's global health, pain assessment and evaluator's global assessment are limited and do not support a positive association with progression of joint damage.

Conclusion: Published data indicate that all DAIs that include swollen joints are related to radiographic progression while, of the individual components, only swollen joints and acute phase reactants are associated. Therefore composite DAIs are the optimal tool to monitor disease activity in patients with RA.