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Background: Rheumatoid Arthritis (RA) is associated with an increased risk for cardiovascular disease (CVD), partially attributable to systemic inflammation and traditional risk factors for CVD. Since physical activity (PA) is strongly related to CVD in the general population, the aim of this thesis was to describe aspects of PA in patients with RA, and further to analyse associations with disease activity, traditional risk factors for CVD and subclinical atherosclerosis.

Methods: In papers I and II, newly diagnosed RA patients were followed for two (n=66) and mean (SD) 16 (2) (n=25) years respectively. Disease activity and aerobic capacity were measured in both groups.​ In paper II, the 25 patients were also examined for traditional risk factors for CVD, body composition, with pulse wave analysis and carotid ultrasound. Self-efficacy was assessed using a questionnaire. In paper III, a combined heart rate and movement monitor was used to measure PA in 84 patients with early (<2 years) and 37 patients with long-standing (mean [SD] 16 [2] years) RA. Data were analysed for associations with disease activity, traditional risk factors for CVD and subclinical atherosclerosis, as above. Finally, in paper IV, a pilot study including 13 patients, median (Q1-Q3) age 57 (44-64) years, was conducted to analyse the feasibility as well as the effects of ten weeks of spinning exercise, on aerobic capacity, traditional risk factors for CVD and inflammation.

Results: In papers I and II, aerobic capacity was maintained at follow-up. In paper I, median (Q1-Q3) aerobic capacity was 31 (27-39) ml/kg x min at baseline and 33 (25-38) ml/kg x min after two years. In paper II, median (Q1-Q3) aerobic capacity was 32 (28-42) ml/kg x min at baseline and 33 (28-39) ml/kg x min after 16 years. In multiple linear regression analyses, adjusted for baseline aerobic capacity, disease activity during the first two years after diagnosis explained 53 % of the aerobic capacity level after 16 years [b=-0.14, p<0.004]. Higher aerobic capacity was associated with more favourable measures of risk factors for CVD and self-efficacy over time and at follow-up. In paper III, 37 % of the patients with early and 43 % of the patients with long-standing RA, did not reach the national recommendations of PA. Total PA as well as more time spent in moderate to vigorous PA were associated with more favourable risk factors for CVD. Patients with higher disease activity and functional disability were less physically active. In paper IV, intensive spinning exercise proved to be a feasible method, that significantly improved aerobic capacity, systolic blood pressure and the number of tender joints.

Conclusions: Aerobic capacity, which could be maintained despite several years of disease, was related to risk factors for CVD and to self-efficacy. Higher disease activity in early disease predicted lower aerobic capacity after 16 years. Higher PA level was associated with a more beneficial cardiovascular profile, however, an insufficient level of PA was found in a substantial proportion of patients. Furthermore, we found, that intensive spinning exercise was a feasible method for the group included, to improve aerobic capacity and blood pressure without detrimental effects on disease activity. Physical activity and aerobic capacity have roles to play in the cardio protective management and are, as other modifiable risk factors, suggested to be estimated regularly. Higher disease activity is known to increase the risk of CVD in RA, and as disease activity also seems to negatively impact future aerobic capacity, interventions and support for health enhancing PA should have high priority in these patients. 

Rheumatoid arthritis (RA) is a systemic and inflammatory disease that has been associated with an increased morbidity and mortality in cardiovascular disease (CVD). Low aerobic capacity is one of the strongest independent risk factors for CVD and all-cause mortality in the general population. In patients with longstanding RA, low aerobic capacity has been related with a worse cardiovascular profile and an increased risk of CVD mortality. As a consequence of this, low aerobic capacity might provide an additional risk factor for CVD in patients with RA. The aim of this thesis was to describe the associations between aerobic capacity and risk factors for CVD as well as disease activity in patients with early RA, and also the effects of intensive exercise therapy on traditional risk factors for CVD and disease activity in patients with longstanding RA.

Paper I, a cross-sectional study including 67 patients with early RA, mean (SD) age 53.1 (14.4), assessments of aerobic capacity, CVD risk factors, disease activity and functional ability were taken. Data were analysed for the associations between aerobic capacity and CVD risk factors and disease activity. In paper II, an intervention study, including 13 patients with RA, median age (Q1-Q3) 57 (44-64) years, aerobic capacity, pulse wave analysis (PWA), CVD risk factors, and disease activity were analysed for changes after 10 weeks of intensive exercise therapy. Additional follow-up was made after 25 weeks.

In paper I, the mean (SD) aerobic capacity was 31.6 (8.7) ml O2/kg/min. CVD risk factors and disease activity were all in favour of patients with higher aerobic capacity. In a multiple regression model, adjusted for age and sex, aerobic capacity was significantly associated with percent body fat (β=-0.502, 95%CI=-0.671;-0.333) and triglycerides (β=-2.365, 95%CI=-4.252;-0.479). In paper II, intensive exercise over ten weeks was shown to be a feasible method to significantly improve aerobic capacity (p=≤0.05), systolic blood pressure (p=≤0.01) and the number of tender joints (p=≤0.05). No detrimental effect on disease activity was recorded.

This thesis adds further knowledge of aerobic capacity and its associations with CVD risk factors and disease activity in patients with RA. Also, intensive exercise therapy was a feasible intervention to improve CVD risk factors. To include assessment of aerobic capacity in regular clinical practice may improve patient management as well as patient outcome in patients with RA.

Bakgrund: Reumatoid artrit (RA, ledgångsreumatism) är en kronisk inflammatorisk sjukdom som i första hand angriper leder, men kan även påverka inre organ. Typiska symptom är ledsvullnad, smärta, morgonstelhet och nedsatt funktion i lederna. Patienter med RA har visat sig ha en ökad risk att insjukna i och avlida i hjärt- och kärlsjukdom. I den allmänna befolkningen har låg syreupptagningsförmåga (kondition) visat sig vara en av de starkaste riskfaktorerna för att insjukna i eller att avlida i hjärt- och kärlsjukdom. Tidigare studier har visat att patienter med RA kan ha låg kondition vilket kan utgöra en riskfaktor för hjärt- och kärlsjukdom även vid RA.

Syfte: Syftet med denna avhandling var att beskriva sambanden mellan kondition och riskfaktorer för hjärt- och kärlsjukdom och sjukdomsaktivitet. Ett annat syfte var att studera hur intensiv cykelträning påverkar kondition, traditionella riskfaktorer och sjukdomsaktivitet hos patienter med RA.

Metod: Studie I är en tvärsnittsstudie, bestånde av 67 patienter med tidig RA, som hade en medelålder på 53 år. De undersöktes avseende; kondition, riskfaktorer för hjärt- och kärlsjukdom och sjukdomsaktivitet för att analysera samband mellan dessa. Studie II är en träningsstudie, bestående av 13 patienter med RA, med en medianålder på 57 år. Kondition, riskfaktorer för hjärt- och kärlsjukdom och sjukdomsaktivitet analyserades för att se förändringar efter tio veckors intensiv cykelträning samt vid en uppföljning efter 25 veckor.

Resultat: I studie I visade den studerade gruppen ett konditionsmedelvärde på 31.6 mL. Sambandsanalyser visade att högre kondition var relaterad till lägre grad av riskfaktorer för hjärt- och kärlsjukdom, samt lägre 10 års risk för hjärt- och kärlsjukdom och sjukdomsaktivitet. I studie II fann vi att tio veckors intensiv cykelträning kan vara en användbar metod för att förbättra kondition, blodtryck och antalet ömma leder. Ingen ökad sjukdomsaktivitet noterades.

Slutsatser: Dessa studier bidrar med kunskap om samband mellan kondition och riskfaktorer för hjärt- och kärlsjukdom samt sjukdomsaktiviteten hos patienter med RA. De visar också att intensiv cykelträning kan vara en effektiv metod att förbättra kondition och blodtryck hos patienter med RA.