How does exercise lower my risk for heart attacks and stroke if I have rheumatoid arthritis (RA)?

One of the three overarching principles defined by the 2009 and the 2016 European League Against Rheumatism taskforce is that patients with rheumatoid arthritis (RA) have a higher risk of cardiovascular disease (CVD) when compared with the general population.^1,2 A 2003 systematic review of 15 randomized controlled trials investigating the effects of exercise on patients with RA found that the cardiorespiratory and muscular strengthening benefits that patients received were in accordance with the recommended exercise guidelines (150 to 300 minutes per week of moderate-intensity activity) for healthy adults. This suggests that any physical activity for patients with RA can be beneficial and does not have to be greater than that of the general population in order to see the same benefits.^3-5

In one of the few studies examining the effects of exercise on CVD risk factors in patients with RA, Stavropoulos-Kalinoglou et al. compared the effects of a six-month high-intensity exercise program with advice on exercise and lifestyle changes for 40 patients with RA in a case-control study.⁶ At six months, the study found that the aerobic capacity (VO₂ max) of the exercise group significantly increased by 17% as compared to the control group (p=0.002). They also found a significant decrease in body fat percentage at six months (2.5%, p<0.05), systolic blood pressure (7.1 mm Hg, p<0.001), triglyceride level (0.3 mmol/L, p<0.05), total cholesterol to high-density lipoprotein (HDL) ratio (0.4, p<0.05), and the resultant 10-year predicted CVD risk of a heart attack or stroke (p<0.05), which is calculated based on these risk factors. Sandstad et al. found similar results in a cross-over study⁷ of 18 patients with inflammatory arthritis enrolled in a 10-week, high-intensity interval training (HIIT) program. The HIIT group (n=9) saw a 1.2% decrease in body mass index (BMI) (p=0.04), a 1.0% decrease in total body fat (p=0.04), a 1.6% decrease in waist circumference (p=0.004), and a 0.6% increase in muscle mass (p=0.03).

A cross-sectional study⁸ of 98 patients with RA found that even very light-intensity activity (1.1 – 1.9 metabolic equivalents [MET]), such as washing the dishes, was inversely associated with cardiovascular markers such as systolic blood pressure (beta=-0.35, 95% confidence interval [CI] [-0.51 – -0.16], p<0.001), BMI (beta=-0.65, CI [-0.75 – -0.51], p<0.001), and insulin resistance (beta=-0.32, CI [-0.48 – -0.12], p=0.002). Another cross-sectional study⁹ by Metsios et al. of 65 patients with RA divided the subjects up into inactive, moderately active, and active groups, using the 33^rd and 66^th percentiles of the International Physical Activity Questionnaire (IPAQ). The results of this study showed a significant difference between the active and inactive groups for systolic blood pressure (17.8, CI [1.3 – 34.3], p=0.031), cholesterol level (1.0, CI [0.2 – 19], p=0.014), insulin resistance (1.4, CI [0.4 – 2.3], p=0.004), and 10-year predicted CVD risk (12.9%, CI [6.4% - 19.4%], p<0.001). A third cross-sectional study¹⁰ of 150 patients with RA found that patients with average fitness (mean VO₂ max=27.1 ml/kg/min, standard deviation [SD]=4.7 ml/kg/min, n=49) were significantly different than the unfit group (mean VO₂ max=15.4 ml/kg/min, SD=1.9 ml/kg/min, n=47) in insulin resistance (p<0.001), BMI (p<0.001), fat mass (p<0.001), and 10-year CVD risk (p=0.003).

Studies of the general population have shown that exercise is associated with a decreased risk of coronary heart disease, stroke, and heart failure.⁴ In a 2013 meta-analysis using 43 studies for ischemic heart disease and 26 for ischemic stroke, Kyu et al. found that more than 8,000 MET-minutes/week was associated with a decreased risk of 25% (relative risk [RR] 0.754, CI [0.704 – 0.809]) for ischemic heart disease and 26% (RR 0.736, CI [0.659 – 0.811)) for stroke.¹¹ In concordance with the 2008 Physical Activity Guidelines for Americans, the American College of Cardiology and American Heart Association have also included aerobic physical activity in their recommendations to reduce CVD risk by reducing low-density lipoprotein cholesterol, non-HDL cholesterol, and blood pressure.¹²

Exercise has an inverse dose-response relationship with CVD mortality in the general population.⁴ A meta-analysis by Wahid et al. used data from 36 prospective cohort studies, 33 concerning CVD and three concerning type 2 diabetes, to examine the relationship between physical activity and CVD incidence and mortality.¹³ The meta-analysis found that an increase from no physical activity to the recommended levels of activity was associated with a 23% decreased risk in CVD mortality (RR 0.77, CI [0.71 – 0.84]) and a 17% decreased risk of CVD incidence (RR 0.83, CI [0.77 – 0.89]).

The results of the studies regarding exercise and CVD in patients with RA showed that physical activity is associated with a decrease in the risk of CVD. While this literature consists mostly of cross-sectional studies, the data still supports the benefits of exercise from a cardiovascular point of view. In addition, older literature reviewing randomized controlled trials, although focusing on musculoskeletal strengthening, found associations in the improvement of cardiovascular health, such as cardiorespiratory fitness. These conclusions are further supported by meta-analyses of studies of the general population and of patients at a high risk of CVD (such as diabetes), in which the results were similar. The results of the studies of the general population can be extrapolated to patients with RA, as they are part of the general population, and used as additional evidence to support the cardiovascular benefits of exercise. Despite the limitations of the cross-sectional study design, the data still has value when examining it against the literature surrounding the association between physical activity and CVD risk reduction.

^References

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