Routine Assessment of Patient Index Data 3 (RAPID3) is a Valid Index for Routine Care in Patients with Osteoarthritis

Abstract

Background/Purpose: RAPID3 (routine assessment of patient index data) is an arithmetic composite index of three Core Data Set, patient self-report, measures: physical function (0-3 converted to 0-10), pain (0-10), and patient global estimate (0-10) for a total of 0-30. It can be completed in the waiting room and can be calculated in only few seconds. Aim of this study was to compare RAPID3 with the Western Ontario and Mc-Master Universities Osteoarthritis Index (WOMAC) in patients with knee or hip osteoarthritis (OA) Methods: patients with symptomatic knee or hip osteoarthritis as main rheumatologic diagnosis (VAS pain > 50 on a visual scale 0-100mm) according to the ACR (American College of Rheumatology) criteria and with stage 2 or 3 according to the Kellgren-Lawrence radiographic criteria were eligible. All subjects were clinically evaluated individually by an experienced rheumatologist and were asked to complete the self-report questionnaires (the original version of the WOMAC for hip or knee osteoarthritis and the RAPID3). There was no specific order in which the tests were completed; rather, each participant selected the order. Agreement between WOMAC and RAPID3 scores was estimated with rho Spearman correlation statistic and Cohen's kappa. Results: 478 patients (155 males, 323 females) with hip (n=38) or knee (n=70) osteoarthritis were enrolled in daily practice clinical care during 2010-2012. Mean age (±SD) was 63±14.4 years old. Mean score was 67±9.1 for WOMAC and 6.5±2.1 for RAPID3. RAPID3 and WOMAC have shown a global correlation rho index of 0.72 (p<0.01) and a Cohen's kappa of 0.7. Computing analysis for diagnosis, the means of WOMAC and RAPID3 weren't significantly different between patients with hip or knee osteoarthritis (67± 9.9 vs 68±6.8 and 6.4±2.1 vs 6.6±2.1, respectively. p>0.05). The Spearman's rho was 0.63 for hip osteoarthritis (p<0.01) and 0.78 for knee osteoarthritis. Cohen's kappa was 0.68 for hip osteoarthritis (p< 0.01) and 0.78 for knee osteoarthritis, respectively. Conclusion: Up to date there's not literature about the use of RAPID3 in patients with OA. In our study we found a strong correlation between RAPID3 and WOMAC in patients with either hip and knee OA, confirmed by a linear regression model developed using all variables collected. RAPID3 provide informative quantitative data for patient status from one visit to the next comparable to other self-reported questionnaire as WOMAC in a time sparing manner.