This is a longitudinal clinical validation study of the PROMIS physical function, fatigue, and pain impact short forms in patients with rheumatoid arthritis (RA). Patients will complete assessments at two points: baseline and 6 months post-baseline. The responsiveness of six PROMIS static forms (physical function \[HAQ, PF-10, 10 and 20 item short forms\], fatigue, and pain impact) will be evaluated for change over the 6-month period. Physical function change scores will be contrasted with established Legacy physical function instruments. The test of "responsiveness" is defined as the ability of the instrument to detect change after major treatment intensification, self-reported improvement in functioning, or positive changes in patient global scores. The order of presentation of forms will be randomly assigned to eliminate questionnaire fatigue or other order effects as factors. We will also evaluate the test-retest reliability of four PROMIS static forms (HAQ and PF-10 physical function, fatigue, and pain impact) in a random subsample of patients at 1-week post-baseline. In addition, we will evaluate convergent validity of PROMIS measures of physical function by comparing self-report with observation of performance of physical function tasks in a subsample of patients randomly selected from the local geographic region.
