Background/Purpose: Treat to target has been shown to improve outcomes in multiple rheumatology diseases although relies on accurate disease measures. Our academic clinic routinely measures RAPID-3 in all patients at clinic check-in. However, a previous survey of our providers found a low confidence in the accuracy of RAPID-3, often attributed to comorbidities. Therefore, we examined whether RADAI-5, which includes questions that our providers felt were more specific for inflammatory arthritis activity, would be a more reliable measure of RA and more accurately predict medication changes in clinic.

Methods: We performed a cross-sectional study over a 4-month time period involving 100 randomly selected rheumatology clinic patients. Patients completed a RADAI-5 and RAPID-3 questionnaire at the beginning of routine clinical visits. Therapy changes, comorbidities (osteoarthritis, fibromyalgia/chronic pain, and mood disorders), and diagnosis were recorded. Pearson correlation coefficients were calculated between RADAI-5 and RAPID-3, and differences in disease activity scores by co-morbidities and diagnosis were estimated by t-tests.

Results: Inflammatory arthritis (IA), which included RA, PsA, IBD-related arthritis, and ReA, was the most common diagnosis (n=45). Both RADAI-5 and RAPID-3 were highly correlated across diagnoses and comorbidities (p<0.001 for all, Figure 1). Comorbidities of OA, FM, and mood disorders uniformly resulted in higher disease activity measures (p=0.01). Across both measures, patients in remission had more medication tapering and patients with high disease activity had more treatment escalation (p=0.1), with this trend continuing when examining IA patients and comorbid patients (Figure 2). However, for patients with intermediate disease activity there was not a clear trend of management, and neither disease activity measure appeared to more accurately reflect medication change in these patients.

Conclusion: Our study confirms a high degree of correlation between RADAI-5 and RAPID-3 across rheumatologic patients, although this relationship is weakened in patients with comorbid OA, FM, or mood disorders. Having one of these comorbid conditions clearly resulted in higher disability on both of the patient-reported measures. Based on the medication changes in this study, it does not appear that either measure provides clear guidance for patients with intermediate disease activity measurements. In order to improve patient care by incorporating patient-reported measures, additional work identifying approaches to decrease confounding by comorbid disease is essential.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-comparison-of-radai5-and-rapid3-disease-measures/