Objective: To develop and assess the reliability and validity of a patient-reported measure of hand activity performance for persons with rheumatoid arthritis (MAP-Hand).
Methods: 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.
Results: 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.
Conclusion: 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.