Obese persons with coronary heart disease have lower all-cause, CVD mortality risk
All-cause and cardiovascular disease (CVD) mortality is reduced among overweight and obese individuals with coronary heart disease, but this obesity paradox is observed only in participants who do not adhere to current recommendations of physical activity, a recent study has found.
“Our study demonstrated that subjects with coronary heart disease who are overweight or mildly obese have better survival than their lean counterparts and that all levels of physical activity are associated with improved survival,” researchers said. “Our results also indicate that among subjects with coronary heart disease who are physically active, BMI does not seem to associate strongly with survival.”
During a median follow-up of 12.5 years, 3,818 patients died (62.1 percent of CV disease). [Am J Med 2017;130:949–957]
Compared with participants with a BMI of 18.5 to 22.4 kg/m2, those with a BMI of 25.0 to 27.4 kg/m2 (hazard ratio [HR], 0.80; 95 percent CI, 0.72 to 0.90), 27.5 to 29.9 kg/m2 (HR, 0.80; 0.71 to 0.90) and 30.0 to 34.9 kg/m2 (HR, 0.83; 0.74 to 0.95) had reduced all-cause mortality risk. Participants in the BMI categories 25.0 to 27.4 kg/m2 (HR, 0.81; 0.70 to 0.94) and 27.5 to 29.9 kg/m2 (HR, 0.83; 0.71 to 0.96) also had reduced CVD mortality risk.
Furthermore, all levels of physical activity correlated with reduced all-cause and CVD mortality risk when compared with physical inactivity. Among those who were physically inactive, all BMI categories >25.0 kg/m2 were associated with reduced all-cause mortality risk (HRs across BMI categories, 0.77, 0.79, 0.79, 0.74). On the other hand, BMI was not associated with survival in participants who were following or exceeding the recommended level of physical activity.
“These results suggest that physical activity is important to improve prognosis in subjects with coronary heart disease and that body weight is of minor importance in secondary prevention as long as the subjects are physically active,” researchers said.
These findings support several previous studies which found a survival advantage associated with overweight and obesity in participants with coronary heart disease. [Heart 2015;101:1631–1638; Lancet 2006;368:666–678; Eur Heart J 2013;34:345–353; Am J Med 2012;125:796–803; Am J Med 2009;122:1106–1114; J Am Coll Cardiol 2009;53:1925–1932; Int J Cardiol 2006;110:153–159; Am J Med 2007;120:863–870; Int J Obes 2016;40:220–228]
“[H]owever, the current study shows the important and significant interaction among BMI, physical activity and prognosis,” researchers said.
In earlier studies, researchers also reported that cardiorespiratory fitness affects the relationship between adiposity and prognosis in individuals with coronary heart disease, an obesity paradox manifested only in those with lower fitness. [Mayo Clin Proc 2012;87:443–451; Am Heart J 2011;161:590–597]
“Our findings of no difference in survival between the different BMI categories in subjects who met or exceeded the recommended level of physical activity are in line with this, recognizing that generally cardiorespiratory fitness correlates better with prognosis than does physical activity,” researchers said. [Prog Cardiovasc Dis 2015;57:306–314]
In this study, the authors followed 6,493 participants (34.4 percent women) with coronary heart disease from the Nord-Trøndelag Health Study, with examinations performed in 1986, 1996 and 2007, to the end of 2014. Adjusted for age, smoking, diabetes, hypertension, self-reported health status and alcohol, Cox proportionate hazard regression was used to estimate HRs for all-cause and CVD mortality.