Association of obesity with heart failure outcomes in 11 Asian regions: A cohort study

Abstract

Background

Asians are predisposed to a lean heart failure (HF) phenotype. Data on the ‘obesity paradox’, reported in Western populations, are scarce in Asia and have only utilised the traditional classification of body mass index (BMI). We aimed to investigate the association between obesity (defined by BMI and abdominal measures) and HF outcomes in Asia.

Methods and findings

Utilising the Asian Sudden Cardiac Death in Heart Failure (ASIAN-HF) registry (11 Asian regions including Taiwan, Hong Kong, China, India, Malaysia, Thailand, Singapore, Indonesia, Philippines, Japan, and Korea; 46 centres with enrolment between 1 October 2012 and 6 October 2016), we prospectively examined 5,964 patients with symptomatic HF (mean age 61.3 ± 13.3 years, 26% women, mean BMI 25.3 ± 5.3 kg/m ², 16% with HF with preserved ejection fraction [HFpEF; ejection fraction ≥ 50%]), among whom 2,051 also had waist-to-height ratio (WHtR) measurements (mean age 60.8 ± 12.9 years, 24% women, mean BMI 25.0 ± 5.2 kg/m ², 7% HFpEF). Patients were categorised by BMI quartiles or WHtR quartiles or 4 combined groups of BMI (low, <24.5 kg/m ² [lean], or high, ≥24.5 kg/m ² [obese]) and WHtR (low, <0.55 [thin], or high, ≥0.55 [fat]). Cox proportional hazards models were used to examine a 1-year composite outcome (HF hospitalisation or mortality). Across BMI quartiles, higher BMI was associated with lower risk of the composite outcome ( p _trend < 0.001). Contrastingly, higher WHtR was associated with higher risk of the composite outcome. Individuals in the lean-fat group, with low BMI and high WHtR (13.9%), were more likely to be women (35.4%) and to be from low-income countries (47.7%) (predominantly in South/Southeast Asia), and had higher prevalence of diabetes (46%), worse quality of life scores (63.3 ± 24.2), and a higher rate of the composite outcome (51/232; 22%), compared to the other groups ( p < 0.05 for all). Following multivariable adjustment, the lean-fat group had higher adjusted risk of the composite outcome (hazard ratio 1.93, 95% CI 1.17–3.18, p = 0.01), compared to the obese-thin group, with high BMI and low WHtR. Results were consistent across both HF subtypes (HFpEF and HF with reduced ejection fraction [HFrEF]; p _interaction = 0.355). Selection bias and residual confounding are potential limitations of such multinational observational registries.

Conclusions

In this cohort of Asian patients with HF, the ‘obesity paradox’ is observed only when defined using BMI, with WHtR showing the opposite association with the composite outcome. Lean-fat patients, with high WHtR and low BMI, have the worst outcomes. A direct correlation between high WHtR and the composite outcome is apparent in both HFpEF and HFrEF.

Trial registration

Asian Sudden Cardiac Death in HF (ASIAN-HF) Registry ClinicalTrials.gov Identifier: NCT01633398

Abstract

Carolyn Lam and colleagues investigate the association of body mass index and waist-to-height ratios with heart failure outcomes in cohorts from 11 Asian regions.

Author summary

Why was this study done?

• Asian heart failure (HF) patients are more likely to have a lean HF phenotype compared to Western patients.

• The obesity paradox, where higher body mass index (BMI) is associated with better HF outcomes, is well-reported in Western populations, but little is known about this paradox in Asia.

• We investigated the association between obesity, defined by traditional BMI versus waist circumference indices, and HF outcomes in Asia.

What did the researchers do and find?

• Among Asian patients with HF, BMI and waist-to-height ratio (WHtR) have directionally opposite relationships with a composite outcome of all-cause death and hospitalisation for HF—lower BMI, but higher WHtR, is associated with worse outcomes.

• In combined analysis, patients who were lean-fat (with low BMI but high WHtR) were more likely to be women, to be from low-income countries or South/Southeast Asia, to have diabetes, and to have worse quality of life scores.

• Lean-fat patients also had the highest rate and risk of the composite outcome (HF hospitalisation and all-cause mortality), irrespective of heart failure subtype (with preserved versus reduced ejection fraction).

What do these findings mean?

• The obesity paradox exists in Asia only when obesity is classified by BMI.

• The relationship between obesity and HF outcomes in Asia is directionally opposite for BMI versus WHtR.

• In this cohort of Asian patients with HF, lean (low BMI) patients with central obesity (high WHtR) had the worst outcomes, both in cases where ejection fraction was reduced and in cases where it was preserved.