Evaluation of joint range of motion (ROM) is important in the therapeutic approach to patients with rheumatoid arthritis (RA). The reliability, construct validity and sensitivity to change of the Escola Paulista de Medicina (EPM)--range of motion scale that measures 10 distinct movements of small and large joints were examined.
Fifty patients with active RA who were participating in an inpatient multidisciplinary treatment program were examined by 2 investigators. Twenty-five of the patients were examined both at admission and at discharge from the hospital.
The mean EPM-ROM score at study entry was 11.52 (SD +/- 3.80). The intra and inter-observer reliability of the EPM-ROM scale was high, with correlations of r = 0.91 and r = 0.85, respectively. There was a good correlation between the EPM-ROM scale and measures of functional ability. Correlations with measures of disease activity were poor. After a mean duration of the treatment program of 4.2 weeks, patients generally improved in variables of functional status and disease activity. The improvement of the EPM-ROM score (mean difference 1.58, 95% CI 0.84-2.32) was generally larger than improvement in other variables of functional status.
The EPM-ROM scale is a reliable instrument, and according to its correlation with measures of functional status, relevant to the performance of activities of daily living. It showed a good response to improvement of functional status and disease activity and was more sensitive to changes than other variables of functional status.