Cardiorespiratory fitness in patients with rheumatoid arthritis is associated with the patient global assessment but not with objective measurements of disease activity

Abstract

ObjectivePatients 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.MethodsVO2peak 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.ResultsWomen 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).ConclusionCRF 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.

Faster age-related decline in cardiorespiratory fitness in rheumatoid arthritis patients: an observational study in the Trøndelag Health Study

“…Thus, more recent exercise regimens for RA patients could potentially have counteracted the decline in eCRF from HUNT2 to HUNT3. This does not seem to have had a strong effect because a study from our group showed that RA patients tested in 2017 still had reduced CRF compared to the healthy population [ 16 ].…”

“…Because HUNT is a large population-based study, RA disease-related variables that would not be relevant for controls such as disease activity, swollen and tender joint counts, or the patient’s global disease assessment were not collected. Previously, our group found that a number of variables describing physical function and disease activity were not associated with measured CRF at CPET in RA patients and did not improve the RA-specific eCRF equation [ 15 , 16 ]. Thus, the results of the present study are probably not biased because such variables were missing.…”

“…Thus, results from this study might not be representative for today’s RA population. In a former study [ 16 ], we investigated various predictors for the measured CRF in RA patients. Disease modifying anti-rheumatic drugs, comorbidities, and disease activity scores other than the patient global assessment were not significant predictors for CRF.…”

“…After demonstrating that these formulas overestimated eCRF in RA patients with the lowest measured CRF, our group developed eCRF equations that more correctly calculate eCRF in RA patients [15]. Previous studies suggest that RA patients are deconditioned and on average have decreased CRF compared to the general population [16][17][18]. To our knowledge, no studies have compared age-related changes in eCRF of RA patients and healthy people in a population-based setting.…”

Reduced cardiorespiratory fitness is a mediator of excess all-cause mortality in rheumatoid arthritis: the Trøndelag Health Study

“…19 CRF is, therefore, an important modifiable risk factor because it may be improved by increasing relevant physical activity (PA). 20 Studies have shown that patients with RA have reduced CRF compared with the healthy population, [21][22][23] whereas PA interventions that improve CRF are associated with increased function and reduction of cardiovascular risk in RA. 24 25 The gold-standard method to measure VO 2max is by cardiopulmonary exercise testing (CPET) either on a treadmill or bicycle ergometer.…”