4 Questions About RAPID3 for RA

Previous studies have suggested routine assessment of patient index data 3 (RAPID3) is reliable and convenient for monitoring disease activity in rheumatoid arthritis (RA).

A prospective study led by Michael Ward, MD, PhD, from the Intramural Research Program within the National Institute of Arthritis and Musculoskeletal and Skin Diseases at National Institutes of Health, sought to measure minimal clinically important improvement (MCII) of RAPID3 in RA.

Dr Ward and colleagues calculated RAPID3 prior to and after treatment escalation among a cohort of adults with active RA. Patient judgment of improvement was used as the standard for a receiver-operating characteristic curve, which approximated MCII.

Overall, the mean RAPID3 improved from 16.3 before treatment escalation to 11.1 after treatment escalation. MCII was -3.8 based on simultaneous optimization of sensitivity and specificity, -3.5 using the 0.80 specificity criterion, and -4.1 using the Youden index. As a result, RAPID3 was deemed clinically meaningful.

Rheumatology Consultant caught up with Dr Ward about his research.

Rheumatology Consultant: What is the current gold standard measure for assessing patients with RA in clinical trials and routine care?

Michael Ward: The standard measure in clinical trials is a disease activity score that is a composite of tender and swollen joint counts, patient ratings of symptoms, and in some measures, a laboratory marker of inflammation in the blood. In routine care, these elements are also used, although not always in the formalized way done in clinical trials. Patient reports of symptoms assessed using standardized questions, such as the RAPID3, are used by some physicians, but not by most.

Study findings, clinical implications >>

RHEUM CON: Why is it important to be able to measure minimal clinically important improvement among patients with RA?

MW: The minimum clinically important difference (MCID) is most useful for clinical trials. If a measure improves after a patient receives a particular treatment, we need to know whether the amount of change is meaningful to most patients. The MCID provides this threshold for a group of patients who had active RA. One can apply this threshold to trials of patients with similar levels of RA activity and get an estimate of the percent of patients with RA who likely have a meaningful benefit from the treatment. 

RHEUM CON: Were you surprised by your study findings?

MW: Dr. Pincus, the developer of the RAPID3, has been using the measure for many years. Some time ago, he estimated the change in RAPID3 that he thought represented a good treatment response, and quite independently, we found his estimate to be spot-on. It was nice to have this confirmation.

RHEUM CON: What are the next steps in your research?

MW: The major emphasis is to expand the use of the RAPID3 as an outcome measure in both trials and in the clinic, as well as to expand its use to other diseases beyond RA.

Reference:

Ward MM, Castrejon I, Bergman MJ, Alba MI, Guthrie LC, Pincus T. J Rheumatol. Minimal clinically important improvement of Routine Assessment of Patient Index Data 3 in rheumatoid arthritis. 2019;46(1):27-30. doi:10.3899/jrheum.180153.

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