Stable Severe Obesity Shown to Increase Severity, Risk of Long-term Heart Failure

Overweight and obese adults with small upward trends in their body mass index (BMI), absent cardiovascular disease (CVD) at baseline, were shown to have greater risk of heart failure, all-cause mortality, and cardiovascular disease–related mortality over 10 years in a recent UK study published in BMC Public Health.

“Although obesity is a well-recognised risk factor for cardiovascular disease (CVD), the impact of long-term BMI changes in overweight or obese adults, on the risk of heart failure, CVD, and mortality has not been quantified,” the authors wrote. “Few studies have explored how BMI in overweight or obese individuals may change over time, and any cardiovascular impact this may have.”

The UK Clinical Practice Research Datalink provided the investigators their data, which represents close to 15% of the UK population for age, sex, and ethnicity. These records were cross referenced with secondary care records (Hospital Episode Statistics) and death registration records from the Office of National Statistics. Overall, 264,230 patients were represented in the study, they had a mean (SD) age of 49.5 (12.7) years and a mean overall baseline BMI of 33.8 (6.1) kg/m2, and 62% were female.

Overall, the mean BMI increase was 1.06 (3.8) kg/m2 over the study’s follow-up, and as the severity of obesity rose, so did the prevalence of hypertension, atrial fibrillation, chronic kidney disease, and type 2 diabetes (T2D).

There were 31,400 cases of CVD for close to 3 million person-years of follow-up. This measure was lower in the overweight-stable group compared with the overall study population, per 1000 person-years: 9.30 (95% CI, 9.12-9.49) vs 10.75 (95% CI, 10.61-10.87).

BMI was classified 4 ways in the study—overweight (28.7 kg/m2), class-1 obesity (33.7 kg/m2), class-2 obesity (39.9 kg/m2), class-3 obesity (49.1 kg/m2)—and measured at baseline, 2 years plus/minus 90 days, 5 years plus/minus 6 months, 8 years plus/minus 6 months, and 10 years plus/minus 21 months. Individuals were excluded if they had preexisting CVD or fewer than 2 measure of BMI. Most patients were White, and the most common comorbidities at baseline were hypertension (19.9%) and T2D (8.6%).

The greatest risks for heart failure and all-cause and CVD-related mortality were seen in the class-3 obesity group:

• Heart failure had a 2.26 higher risk of occurring (HR, 3.26; 95% CI, 2.98-3.57)
• All-cause mortality had a 1.72 greater risk (HR, 2.72; 95% CI, 2.58-2.87)
• CVD-related mortality had a 2.31 greater risk (HR, 3.31, 95% CI, 2.84-3.86)

These individuals also died at the youngest age and had the earliest onset of incident CVD.

The investigators analysis also shows a substantial uptick in heart failure incidence from the overweight-stable to the class-3 obesity classification: 1.70 (95% CI, 1.6-1.8) to 5.70 (95% CI, 5.3-6.1; P < .0001) per 1000 person-years. However, most individuals in the study did maintain a consistent degree of obesity.

Of the 24,022 deaths over the course of the study, 11.8% were related to CVD.

The authors noted that higher rates of obesity were seen at lower levels of socioeconomic status, “confirming that this is disproportionately an issue in the materially deprived,” they said.

They added that their findings contribute value to the literature, because their study was the first to “to assess the effect of long-term BMI changes, rather than single BMI measures, on the risk of CVD and related outcomes.” Plus, their findings echo those from another Canadian study also showing elevated risk despite no significant BMI change.

“Our study provides compelling evidence of poor health outcomes associated with obesity,” they concluded. “More effective policies and weight-management interventions at societal, cultural and health service levels are needed to address this increasing burden. Further research is also needed to explore whether interventions to change BMI trajectories would have an impact on future CVD outcomes.”

Reference

Iyen B, Weng S, Vinogradova Y, Akyea RK, Qureshi N, Kai J. Long-term body mass index changes in overweight and obese adults and the risk of heart failure, cardiovascular disease and mortality: a cohort study of over 260,000 adults in the UK. BMC Public Health. Published online April 15, 2021. doi:10.1186/s12889-021-10606-1