Osteoarthritis (OA) commonly is regarded as less severe than rheumatoid arthritis (RA). However, limited data are available for direct comparisons, largely because different measures traditionally are used in RAprimarily a HAQ (Health Assessment Questionnaire) vs OAa WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index). RAPID3 (Routine Assessment of Patient Index Data) on an MDHAQ (Multi-Dimensional HAQ) is a self-report index that is informative in RA and most rheumatic

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... es, including OA. 1 A recent analysis of unselected patients from 4 rheumatology settings indicated that RAPID3 and other MDHAQ scores were similar or higher in OA versus RA patients, 2 but those findings were from a cross-sectional convenience sample of unselected patients likely affected by treatment, rather than from an initial visit prior to rheumatologic therapy. Objectives: To analyse MDHAQ/RAPID3 scores in patients with a primary diagnosis of either OA or RA at their initial visit and at 6 month follow-up at an academic rheumatology centre. Methods: At one site, all patients complete an MDHAQ/RAPID3 prior to seeing the rheumatologist. The 2-page MDHAQ/RAPID3 includes 0-10 scores for physical function (FN) (converted from 0-3) and visual analogue scale (VAS) scores for pain (PN) and patient global assessment (PATGL), compiled into a 0-30 RAPID3. New patients seen between 2013 and 2017 with physician-diagnosed primary OA or RA and compete RAPID3 data were studied. Mean FN, PN, PATGL and RAPID3 scores in RA and OA at baseline and 6 month follow-up (range 3-9 months) were compared for differences between first and second visits using ttests, and between OA and RA using MANOVA. Results: At first visit, mean RAPID3 was 15.9 in OA vs 15.3 in RA (table 1) . At a mean of a 5 month (actual) follow-up visit, RAPID3 fell from 15.9 to 14.9 (-1.0, p=0.06) in OA vs 15.3 to 11.1 (-4.2, p<0.001) in RA, resulting in significantly higher scores in OA vs RA (table 1). These differences remained significant adjusted for age, sex, body mass index, and education level. Mean and standard deviation (SD) at first visit and 5 month follow up visit MDHAQ/RAPID3 of patients with OA and RA seen in routine care