Severe Obesity Persists, Takes High Cardiovascular Toll

Marlene Busko
April 21, 2021

In a UK cohort of more than 260,000 mostly middle-aged adults in primary care with overweight or obesity, body mass index (BMI) remained relatively stable over a decade.

However, compared to overweight individuals, those with severe (class 3) obesity were more socioeconomically disadvantaged and had triple the risk for incident heart failure or all-cause or cardiovascular disease (CVD)–related mortality in a study published online April 15 in BMC Public Health.

"This is the first study to evaluate the long-term impact of overweight and obese individuals' BMI trajectory on cardiovascular endpoints, heart failure, and mortality outcomes," write Barbara Iyen, PhD, MPH, University of Nottingham, Nottingham, United Kingdom, and colleagues.

The findings emphasize "the high cardiovascular toll exacted by continuing failure to tackle obesity, particularly among more socio-economically deprived populations," they warn.

"We have found that despite widespread efforts to prevent and manage obesity, the majority of adults who are overweight or obese in the general population continue to remain so in the long term," Iyen summarized in a statement from her university.

"More effective policies and weight-management interventions are needed urgently to address this increasing burden and associated adverse health outcomes," she stressed.

Invited to comment, Sadiya S. Khan, MD, Northwestern University Feinberg School of Medicine, Chicago, Illinois, said: "This research adds to the growing body of evidence [that] earlier and more intensive interventions for weight loss are necessary to promote cardiovascular health and reduce morbidity and mortality."

"Adjunctive pharmacotherapy and bariatric surgery are both options that should be considered in addition to intensive lifestyle interventions in overweight and obesity groups," she added in an email to Medscape Medical News.

"I would always advocate for earlier prevention efforts focused on weight loss, because years lived with obesity are associated with future CVD, so every year counts," Khan continued.

Does BMI Remain Elevated, Predict Worse Heart Health?

Although obesity is a well-recognized risk factor for CVD, long-term changes in BMI and the impact of BMI on the risk for heart failure, CVD, and mortality have not been quantified among adults with overweight and obesity, Iyen and colleagues explain.

The researchers examined data from the UK Clinical Practice Research Datalink and secondary care and mortality records to determine BMI trajectories among adults with overweight or obesity and to quantify the risk for heart failure, CVD (defined as coronary heart disease, stroke, transient ischemic attack [TIA], or peripheral vascular disease [PVD]), CVD-related mortality, and all-cause mortality.

They identified 264,230 adults with overweight or obesity who were seen in 790 primary care practices in the United Kingdom from 1999 to 2018 and who did not initially have heart failure or CVD and for whom baseline BMI measurements and at least one other BMI measurement 2, 5, 8, and 10 years later were available.

The researchers divided the cohort into four groups on the basis of initial BMI: overweight (36% of patients; mean BMI, 28.7 kg/m2); class 1 obesity (40%; mean BMI, 33.7 kg/m2); class 2 obesity (19%; mean BMI, 39.9 kg/m2), and class 3 obesity (5%; mean BMI, 49.1 kg/m2).

The mean age of the individuals was 50 years, and 64% were White. Race/ethnicity data were unavailable for 31%. There few were Asian Indian, Asian, or Black patients in the chort (5%).

'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, 7662 incident cases of heart failure, and 24,022 deaths, of which 2827 (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 adjusting 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 note, 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 emphasize.

"Further research is...needed to explore whether interventions to change BMI trajectories would have an impact on future CVD outcomes," they conclude.

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. Khan has disclosed no relevant financial financial relationships.

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Reviewed on 4/21/2021
References
SOURCE: Medscape, April 21, 2021. BMC Public Health. Published online April 15, 2021.

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