Background/Purpose:   Patient-reported outcomes measurement information system (PROMIS) 29 is recommended by the National Institute of Health (NIH) consensus panel as the preferred battery of measures to collect in musculoskeletal pain treatment studies. Physical function domain in the PROMIS29 short form has only 4 questions. We compared Routine Assessment of Patient Index 3 (RAPID3) scores based on multi-dimensional health assessment questionnaire (MD-HAQ)-based and patient-reported outcomes measurement information system (PROMIS) 29 to determine the degree of agreement.

Methods:  For rheumatoid arthritis (RA) subjects enrolled in the University of Pittsburgh Rheumatoid Arthritis Comparative Effectiveness Registry (RACER), a cross-sectional analysis was performed for all RACER patients who completed MD-HAQ and PROMIS29 short form.  Physical function based on PROMIS29 (PROMIS29-PF) was calculated using raw score of PROMIS29 physical function (PROMIS29-PF = ([20- PROMIS29-PF]/2). Association between physical function based on MD-HAQ and PROMIS29 was evaluated by Pearson¡¯s correlation coefficient.  Bland-Altman 95% limits of agreement (LOA), kappa statistics, Lin¡¯s concordance coefficient were used to measure the agreement between RAPID3 score based on MD-HAQ and PROMIS29 (RAPID3-PROMIS).  

Results:   For the 397 subjects analyzed, age was 64.2 +/- 13.8 (mean +/- SD) years with disease duration of 13.9 +/- 13.1 years. PROMIS-PF was strongly correlated with physical function based on MD-HAQ (r = 0.83, p <0.0001). Overall agreement between disease severity categories of RAPID3 and RAPID3-PROMIS were substantial (percent agreement = 87.7, kappa = 0.83) (Table).   RAPID3 scores (0-10) were slightly different (RAPID3 = 3.4, RAPID3-PROMIS = 3.6, p <0.01). LOA for RAPID3 score were -0.98 and 0.65, with bias of -0.42 (Figure).  Lin¡¯s coefficient of concordance showed substantial agreement (0.976).

Conclusion:   There was very good agreement in RAPID3 scores based on MD-HAQ and PROMIS29 short form. Very low bias score and small values for LOA indicate that RAPID3 scores based on MD-HAQ and PROMIS29 are interchangeable.