“Strong significant gradient in heart failure risk”
Compared to the overweight (reference) group, the severe-obesity group comprised a higher percentage of women (74% vs. 70%), and the prevalence of comorbidities and socioeconomic deprivation was higher.
BMI remained relatively stable in each BMI group. The mean BMI increase was 1.06 kg/m2 during a median follow-up of 10.9 years.
There were 30,400 incident cases of CVD, 7,662 incident cases of heart failure, and 24,022 deaths, of which 2,827 (11.8%) were from CVD.
The risk for heart failure and CVD-related or all-cause mortality increased with increasing obesity severity.
Compared with overweight individuals, those with class 3 obesity were at significantly increased risk for heart failure (hazard ratio [HR], 3.26), all-cause mortality (HR, 2.72), and CVD-related mortality (HR, 3.31) after adjustment for age, sex, and comorbidities (hypertension, type 2 diabetes, atrial fibrillation, and chronic kidney disease).
The risk for stroke/TIA or coronary heart disease was similar among those with severe obesity and the other individuals. The risk for PVD was significantly lower (HR, 0.73).
The reduced risk for PVD in the most severely obese group is similar to findings in the Framingham heart study, the authors noted, and may be due to underdiagnosis or differences in the underlying mechanism.
Compelling evidence of poor health outcomes associated with obesity
Study limitations include the fact that the findings may not be generalizable to other race/ethnicity groups, the lack of information on diet and exercise, and the fact that BMI was used as a surrogate of adiposity. As such, it does not account for an age-related decrease in heavier-than-fat muscle mass and differences between sexes and ethnic groups.
The finding of stable obesity over time accords with two smaller studies that included Canadian and American adults.
The current study did not uncover an obesity paradox, unlike some studies that included patients with preexisting CVD or a history of acute coronary events. Those studies reported better clinical outcomes among patients with overweight or obesity.
The current study included individuals who did not initially have CVD. Those with more severe obesity were younger than individuals with overweight at the time of the occurrence of incident CVD (age 64 vs. 66) and at the age of death (age 67 vs. age 75), which “provides compelling evidence of poor health outcomes associated with obesity,” the authors emphasized.
“Further research is ... needed to explore whether interventions to change BMI trajectories would have an impact on future CVD outcomes,” they concluded.
Dr. Iyen’s clinical academic lectureship is fully funded by the National Institute for Health Research (NIHR). The views expressed are those of the authors and are not necessarily those of the National Health Service, the NIHR, or the Department of Health and Social Care. Dr. Khan has disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.