Cardiorespiratory fitness levels and their association with cardiovascular profile in patients with rheumatoid arthritis: a cross-sectional study

Objective. The aim of this study was to investigate the association of different physical fitness levels [assessed by the maximal oxygen uptake (VO(2)max) test] with cardiovascular disease (CVD) risk factors in patients with RA. Methods. A total of 150 RA patients were assessed for cardiorespiratory fitness with a VO(2)max test and, based on this, were split in three groups using the 33rd (18.1 ml/kg/min) and 66th (22.4 ml/kg/min) centiles. Classical and novel CVD risk factors [blood pressure, body fat, insulin resistance, cholesterol, triglycerides, high-density lipoprotein (HDL), physical activity, CRP, fibrinogen and white cell count], 10-year CVD risk, disease activity (DAS28) and severity (HAQ) were assessed in all cases. Results. Mean VO(2)max for all RA patients was 20.9 (S.D. 5.7) ml/kg/min. The 10-year CVD risk (P = 0.003), systolic blood pressure (P = 0.039), HDL (P = 0.017), insulin resistance and body fat (both at P< 0.001), CRP (P = 0.005), white blood cell count (P = 0.015) and fibrinogen (P< 0.001) were significantly different between the VO(2)max tertiles favouring the group with the higher VO(2)max levels. In multivariate analyses of variance, VO(2)max was significantly associated with body fat (P< 0.001), HDL (P = 0.007), insulin resistance (P< 0.003) and 10-year CVD risk (P< 0.001), even after adjustment for DAS28, HAQ and physical activity. Conclusion. VO(2)max levels are alarmingly low in RA patients. Higher levels of VO(2)max are associated with a better cardiovascular profile in this population. Future studies need to focus on developing effective behavioural interventions to improve cardiorespiratory fitness in RA.