Objective Patients with rheumatoid arthritis (RA) suffer from more cardiovascular disease (CVD), and develop cardiovascular risk factors at an earlier age than the general population. Cardiorespiratory fitness (CRF) is an important predictor of cardiovascular health. There are few data regarding CRF of RA patients, measured as peak oxygen uptake (VO2peak) by the gold standard method; cardiopulmonary exercise testing. We compared CRF in RA patients to those from a healthy population, and investigated if risk factors for CVD and RA-specific variables including subjective and objective disease activity measures were associated with CRF in RA patients.
Methods VO2peak tests of RA patients (n=93) were compared to those of an age-matched and gender-matched healthy population (n=4631) from the Nord-Trøndelag Health Study. Predictors of VO2peak were found using Lasso (least absolute shrinkage and selection operator) regression, followed by standardised multiple linear regression.
Results Women with RA ≥40 years and men with RA aged 40–49 years or 60–69 years had up to 20% lower CRF than the healthy population in the same age groups. By relative importance, body mass index (standardised coefficient=−0.25, p<0.001), physical activity level (coefficient=0.21, p<0.001), patient global assessment (PGA; coefficient=−0.14, p=0.006), systolic blood pressure (coefficient=−0.12, p=0.016), resting heart rate (coefficient=−0.11, p=0.032) and smoking (coefficient=−0.10, p=0.046) were significant predictors of CRF (R2=0.82, gender-adjusted and age-adjusted).
Conclusion CRF in RA patients was lower than in a healthy population. CRF was associated with common risk factors for CVD and the PGA score. Focusing on fitness in RA patients may improve cardiovascular health.
- rheumatoid arthritis
- cardiovascular disease
- patient perspective
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Contributors Study conception and design: MHL, MH, UW, RT, VV. Acquisition and analysis of data: MHL, TF, VV. Interpretation of data: MH, UW, RT, VV. Drafting the manuscript: MHL, TF, VV. Revising the manuscript critically for important intellectual content: MH, TF, UW, RT, VV. All authors approved the final version of the manuscript.
Funding This project is funded by a grant to Marthe Halsan Liff from The Central Norway Regional Health Authority, allocated via The Liaison Committee for Education, Research and Innovation in Central Norway (2016/29014). NeXt Move is funded by the Faculty of Medicine at NTNU and Central Norway Regional Health Authority.
Competing interests None declared.
Patient consent for publication All participants provided written informed consent.
Ethics approval The Regional Committee for Medical and Health Research Ethics approved the study (2016/275), which was performed in compliance with the Declaration of Helsinki.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No additional data are available.
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