AB0367 Influence of Comorbidities on the Functional Capacity and Mobility of Individuals with Rheumatoid Arthritis: A Cross-Sectional Study

Abstract

Background Comorbidities in rheumatoid arthritis (RA) are associated with different outcomes.1 Although some studies have shown associations between such comorbidities and functional incapacity, studies are needed to assess their influence on the mobility of individuals with RA.2,3 Objectives To establish the prevalence of comorbidities in RA patients and to assess their influence on the functional capacity and mobility of the affected individuals. Methods In a cross-sectional study we included 60 patients with RA fulfilling the American College of Rheumatology criteria (ACR, 1987) over a period of 11 months. Comorbidities were assessed by means of three indicators: (i) total number of comorbidities; (ii) the Charlson Comorbidity Index (CCI)4; and (iii) the Functional Comorbidity Index (FCI)5. The activity of disease was evaluated by the Disease Activity Score 28 (DAS28/ESR). The participants' functional capacity was measured using the Health Assessment Questionnaire (HAQ), and their mobility was measured using the Five-Times-Sit-to-Stand (FTSTS)6 and Timed Get Up and Go (TUG)7 tests. Statistical analysis was performed using log-linear stepwise multiple regression at 5% significance level. Results The prevalence of comorbidities in the investigated sample of patients with RA was 90% when the total number of comorbidities was taken into consideration. In the final multiple regression model, the independent factors that influenced functional capacity (HAQ) were activity of disease (DAS28/ESR) and comorbidities, as assessed by FCI. The adjusted R2 of these factors taken as a whole was 0.329. With respect to the participants' mobility (FTSTS and TUG), only the independent factor comorbidities (FCI) exerted a significant influence on the results. The FCI scores explained 19.1% of the FTSTS variability (R2=0.191) and 19.5% of the TUG variability (R2=0.195). Conclusions Comorbidities were highly prevalent in individuals with RA and exerted a negative influence on their functional capacity and mobility. FCI proved to be satisfactory to assess the association between comorbidities and physical function in individuals with RA. References Gullick NJ, Scott DL. Co-morbidities in established rheumatoid arthritis. Best Pract Res Clin Rheumatol 2011; 25:469-483. Radner H, Smolen JS, Aletaha D. Impact of comorbidity on physical function in patients with rheumatoid arthritis. Ann Rheum Dis 2010; 69:536-541. Norton S, Koduri G, Nikiphorou E, et al. A study of baseline prevalence and cumulative incidence of comorbidity and extra-articular manifestations in RA and their impact on outcome. Rheumatology (Oxford) 2013; 52:99-110. Charlson ME, Pompei P, Ales KL, et al. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987;40:373-383. Groll DL, To T, Bombardier C, et al. The development of a comorbidity index with physical function as the outcome. J Clin Epidemiol 2005;25:595-602. Bohannon RW. Sit-to-stand test for measuring performance of lower extrem...