Aerobic capacity is associated with disease activity and cardiovascular risk factors in early rheumatoid arthritis

The aim of this study was to investigate aerobic capacity and its associations with disease activity and risk factors for cardiovascular disease (CVD) in early rheumatoid arthritis (RA).

This cross-sectional study included 67 patients with early RA. Aerobic capacity was estimated with the Åstrand submaximal test adjusted according to the Nord-Tröndelag Health Study formula. The following were also assessed: subclinical atherosclerosis by carotid intima-media thickness and pulse wave analysis; body composition by dual X-ray absorptiometry; estimated CVD mortality risk by the Systematic Coronary Risk Evaluation; disease activity by the Disease Activity Score 28, C-reactive protein and erythrocyte sedimentation rate; blood lipids by total cholesterol, low-density lipoproteins, high-density lipoproteins, and triglycerides; and functional ability by the Stanford health assessment questionnaire. Univariate and multiple linear regression analyses were performed to explore the associations between variables.

The mean (SD) aerobic capacity was 31.6 (8.7) ml O₂ ^-1 kg min^-1 . Disease activity and risk factors for CVD were more favourable for patients with aerobic capacity above the median value. Aerobic capacity was associated with ESR and several CVD risk factors, independent of age and sex. In a multiple regression model that was adjusted for age and sex, aerobic capacity was significantly associated with per cent body fat (β = -0.502, 95% CI [-0.671, -0.333]) and triglycerides (β = -2.365, 95% CI [-4.252, -0.479]).

Disease activity and risk factors for CVD were in favour for patients with a higher aerobic capacity. Aerobic capacity was associated with disease activity and several risk factors for CVD, independent of age and sex. In RA, these findings may provide insights into the benefits of using aerobic capacity as a marker to prevent CVD.