Physical activity associated with less CVD mortality in CHD patients
Sustained Physical Activity, Not Weight Loss, Associated With Improved Survival in Coronary Heart DiseaseLiterature - Moholdt T, Lavie CJ, and Nauman J. - J Am Coll Cardiol 2018;71:1094–101
Introduction and methods
Obesity is associated with the development of coronary heart disease (CHD), and guidelines recommend that patients should maintain or achieve a normal body mass index (BMI) . On the other hand, data show that CHD patients with high BMI have a better prognosis and weight fluctuations over time are associated with a worse prognosis. Furthermore, there is no obesity paradox in CHD patients with a high level of physical activity (PA) .
In this analysis, the associations between long-term BMI and PA changes and all-cause and CVD mortality were examined, in subjects with CHD. For this purpose, CHD participants in the HUNT (Nord-Trøndelag Health Study) study  were included, who had either angina pectoris (AP) or myocardial infarction (MI), and available data on PA, BMI, diabetes mellitus, self-reported health, blood pressure, smoking, and alcohol consumption. Eligible individuals were classified into 3 PA levels (inactive, low PA, and high PA) based on a previously published index , and PA changes were then categorized into 9 categories (inactive-inactive, inactive-low, inactive-high, low-inactive, low-low, low-high, high-inactive, high-low, and high-high).
The primary outcome was all-cause mortality, and the secondary outcome was CVD mortality.
- 3307 participants were followed-up for a median of 15.7 years, and 1493 died.
- Compared with having a stable BMI, those who lost weight (BMI < -0.10 kg/m2/year) had a 30% increased all-cause mortality risk (HR: 1.30; 95%CI: 1.12-1.50), whereas weight gain (BMI ≥0.10 kg/m2/year) was not significantly associated with mortality risk.
- In normal-weight subjects, weight loss was associated with 38% increased all-cause mortality risk (HR: 1.38; 95%CI: 1.11-1.72), whereas weight gain was associated with 25% decreased all-cause mortality risk (HR: 0.75; 95%CI: 0.56-0.99).
- In overweight and obese subjects, neither weight loss nor weight gain was associated with all-cause mortality risk.
- Weight loss was associated with 36% increased CVD mortality (HR: 1.36; 95% CI: 1.12 to 1.65), whereas weight gain did not associate with CVD mortality.
- Increased CVD mortality risk associated with weight loss in normal-weight subjects (HR: 1.47; 95%CI: 1.09-1.98).
- There was a significantly reduced all-cause mortality risk in those who maintained low PA (HR: 0.81; 95%CI: 0.67-0.97), in those who maintained high PA over time (HR: 0.64; 95%CI: 0.50-0.83), in those who changed from low PA to inactive (HR: 0.82; 95%CI:0.70-0.96) and in those who changed from high PA to low PA (HR: 0.74; 95%CI: 0.600.92), compared with those who were inactive over time.
- A significantly reduced CVD mortality risk was observed only in those who maintained a high level of PA over time (HR: 0.62; 95%CI: 0.43-0.89) and in those who changed from inactive to high PA (HR: 0.68; 95%CI: 0.47-0.97).
In a large cohort of subjects with CHD, all-cause and CVD mortality was increased in individuals who lost weight, compared with those being weight stable, especially in those who had a normal weight at baseline. Maintaining or increasing PA was associated with substantial reductions in CVD mortality risk . These results support the role of PA in the secondary prevention of CVD.
In his editorial article, Bouchard  notes that the study published by Moholdt et al. provides important additional information regarding the associations of weight and physical activity changes with mortality rates. However, there are limitations, including the use of BMI instead of body weight changes as a main measure, the self-reported nature of physical activity assessment, which is likely to result in overestimations, and the fact that weight and PA changes were reciprocally adjusted for, although changes in PA are correlated with weight changes.
The author concludes: ‘In summary, the study of Moholdt et al. adds to our understanding of the role of long-term changes in body weight and PA level on mortality rates of individuals who have already experienced a CHD event. The findings add to the body of data suggesting that promoting regular PA in CHD patients is likely to save lives.’