Validity and responsiveness of the Michigan Hand Questionnaire in patients with rheumatoid arthritis: a multicenter, international study.
OBJECTIVE
Millions of patients experience the disabling hand manifestations of rheumatoid arthritis (RA), yet few hand-specific instruments are validated in this population. Our objective was to assess the reliability, validity, and responsiveness of the Michigan Hand Questionnaire (MHQ) in patients with RA.


METHODS
At enrollment and at 6 months, 128 RA patients with severe subluxation of the metacarpophalangeal joints completed the MHQ, a 37-item questionnaire with 6 domains: function, activities of daily living (ADL), pain, work, aesthetics, and satisfaction. Reliability was measured using Spearman's correlation coefficients between time periods. Internal consistency was measured using Cronbach's alpha. Construct validity was measured by correlating MHQ responses with the Arthritis Impact Measurement Scales 2 (AIMS2). Responsiveness was measured by calculating standardized response means (SRMs) between time periods.


RESULTS
The MHQ demonstrated good test-retest reliability (r = 0.66, P < 0.001). Cronbach's alpha scores were high for ADL (α = 0.90), function (α = 0.87), aesthetics (α = 0.79), and satisfaction (α = 0.89), indicating redundancy. The MHQ correlated well with AIMS2 responses. Function (r = -0.63), ADL (r = -0.77), work (r = -0.64), pain (r = 0.59), and summary score (r = -0.74) were correlated with the physical domain. Affect was correlated with ADL (r = -0.47), work (r = -0.47), pain (r = 0.48), and summary score (r = -0.53). Responsiveness was excellent among arthroplasty patients in function (SRM 1.42), ADL (SRM 0.89), aesthetics (SRM 1.23), satisfaction (SRM 1.76), and summary score (SRM 1.61).


CONCLUSION
The MHQ is easily administered, reliable, and valid to measure rheumatoid hand function, and can be used to measure outcomes in rheumatic hand disease.