Clinical assessment of disease activity in rheumatoid arthritis: evaluation of a functional test.

A cross sectional analysis of the correlation between clinical, laboratory, and radiological markers of disease activity in 98 patients with classical rheumatoid arthritis (RA) is reported. The median age was 38 years, the median age at onset of disease 29 years, and the median duration of disease seven years. The Keitel function test (KFT) showed good correlation with the Ritchie articular index (RAI) (p less than 0.0001; r = 0.5) and the disability questionnaire (DQ) (p less than 0.0001; r = 0.6). The RAI and DQ correlated weakly with laboratory variables, while the KFT showed significant correlation with the erythrocyte sedimentation rate (ESR), C reactive protein (CRP), and plasma viscosity (PV) (p less than 0.001; r = 0.4; 0.3; 0.4). Only the KFT showed significant correlations with bone mass measurements (p less than 0.01; r = -0.3; -0.4), and the Larsen index at the right wrist (p less than 0.0001; r = 0.4). Consensus analysis suggested that the KFT is a useful single clinical test of disease activity in RA. The hand functional index (HFI), a component of the KFT, showed significant correlation with the total KFT (r = 0.9). Prospective drug trials are needed to establish the value of the HFI in the monitoring of patients with RA.