Disease Burden in Osteoarthritis Is Similar to That of Rheumatoid Arthritis at Initial Rheumatology Visit and Significantly Greater Six Months Later

Abstract

Objective: To analyze disease burden in osteoarthritis (OA) according to Multidimensional Health Assessment Questionnaire (MDHAQ)/Routine Assessment of Patient Index Data 3 (RAPID3) scores at the initial visit and the 6-month follow-up visit, compared with rheumatoid arthritis (RA) as a benchmark for high disease burden.

Methods: All patients with all diagnoses at the Rush University Medical Center Division of Rheumatology complete a paper MDHAQ at all visits, saved as a PDF in the electronic health record. MDHAQ 0-10 scores for physical function, pain, and patient global assessment (compiled into RAPID3 0-30 scores) and additional scales at the initial and 6-month follow-up visits, for new OA and RA patients seen from 2011 to 2017, were compared. OA and RA patients were classified as self-referred or physician-referred, and RA patients were classified as disease-modifying antirheumatic drug (DMARD)-naive or having prior-DMARD treatment. Patient groups were compared using t-tests and analysis of variance, adjusted for age, disease duration, body mass index (BMI), education, and ethnicity.

Results: Compared with RA patients, OA patients had higher age, BMI, and disease duration. At initial visit, the mean RAPID3 did not differ significantly in OA versus DMARD-naive RA patients, whether self- or physician-referred (range 14.8-16.4 [P = 0.38]), or in all OA patients versus DMARD-naive RA patients versus prior-DMARD RA patients (15.0, 15.7, and 15.8, respectively [P = 0.49]). After 6 months, RAPID3 was improved to 13.3, 10.3, and 10.8, respectively, which represented substantially greater improvement in RA patients than OA patients (P < 0.001). Similar results were seen for most self-reported measures and in adjusted analyses.

Conclusion: MDHAQ/RAPID3 scores are similar in OA and RA patients at the initial visit, but higher in OA patients than in RA patients 6 months later, reflecting superior RA treatments. The same MDHAQ/RAPID3 allows comparisons of disease burdens in different diseases.