Development and psychometric testing of the patient-reported measure of activity performance of the hand (MAP-Hand) in rheumatoid arthritis

Abstract

To develop and assess the reliability and validity of a patient-reported measure of hand activity performance for persons with rheumatoid arthritis (MAP-Hand). The development of the measure included a literature review, semi-structured interviews with 60 patients with rheumatoid arthritis, and testing of face and content validity by video-observation and classification of the initial items according to standardized methods. Further testing followed 2 surveys of 176 and 134 patients with rheumatoid arthritis and included Rasch analysis and comparing MAP-Hand scores with other measures of symptoms and functional ability. Test-retest reliability was assessed in 35 stable patients with rheumatoid arthritis. Most of the initial 31 items had good face and content validity. Following Rasch analysis the measure was reduced to 18 items, which had good evidence for unidimensionality, a broad range of item difficulty, good person separation and ordered thresholds in a 4-point scale. The test-retest intraclass correlation coefficient was 0.94 (95% confidence interval 0.89, 0.97), indicating high reliability. The results of validity testing generally followed the a priori hypotheses, with MAP-Hand scores having moderate to high correlations with scores for the other measures. The MAP-Hand is an 18-item patient-reported measure of hand activity performance, which showed good evidence for reliability and validity in patients with rheumatoid arthritis.