Responsiveness and sensitivity of PROMs to change in disease activity status in early and established rheumatoid arthritis.

Objectives: To determine whether patient reported outcome measures (PROMs) capturing activity limitations, health impact, pain, fatigue and work ability are responsive and sensitive to changes in disease activity status in patients with early and established rheumatoid arthritis (RA).

Methods: All early RA patients (n = 557) from the tREACH-trial and established RA patients (n = 188) from the TARA-trial were included. Both studies were multicentre, single-blinded trials with a treat-to-target management approach. The following PROMs were studied: Health Assessment Questionnaire Disability Index(HAQ-DI), morning stiffness severity, EQ-5D, general health, 36-item short form(SF-36), joint pain, fatigue and productivity loss. Mean changes in PROMs between two consecutive visits were compared with changes in disease activity status(remission, low disease activity and active disease) using linear mixed models and standardised response means. Additionally, the proportion of individual observations that showed an expected PROM response to disease activity status alterations was calculated.

Results: HAQ-DI, morning stiffness severity, general health, EQ-5D and joint pain demonstrated responsiveness to improvement or worsening of disease activity status in both early and established RA. SF-36 physical and mental component scale, fatigue and productivity loss did not show this effect in both groups. Across nearly all PROMs, the magnitude of change and the proportion of individual observations that reflect a shift from and to active disease remained low.

Conclusion: HAQ-DI, morning stiffness severity, EQ-5D, general health and joint pain are responsive to disease activity status alterations on a group level in both early and established RA. For the individual patient the responsiveness of these PROMs is poor.

Clinical Trial Registration: tREACH trial (www.isrctn.com, ISRCTN26791028) and TARA trial (www.onderzoekmetmensen.nl, NTR2754).