Obesity paradox in heart failure with and without diabetes mellitus: a retrospective cohort study

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Heart failure (n=8383). Intervention: Overweight status (BMI ≥ 23 kg/m2) vs. Lean status (BMI < 23 kg/m2). Primary outcome: One-year post-discharge mortality (overweight diabetic vs lean diabetic) (HR 0.65, 95% CI 0.53-0.79, p=<0.001).

Q: What does this research mean for the field?

Overweight status is associated with a significantly lower one-year mortality risk compared to lean status in heart failure patients, regardless of their diabetes status. Novelty: ClaimNovelty.CONFIRMATORY. Consensus alignment: ConsensusAlignment.SUPPORTS_CONSENSUS.

Ohchul Kwon; Minjae Yoon; Jin Joo Park

doi:10.1007/s00392-026-03007-0

September 8, 2026Clinical Research in CardiologyOpen Access

Obesity paradox in heart failure with and without diabetes mellitus: a retrospective cohort study

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Key result

Overweight status (BMI ≥ 23 kg/m2) was associated with a significantly lower one-year mortality risk compared to lean status in heart failure patients with diabetes (adjusted HR 0.65) and without diabetes.

Why the study?

While obesity worsens diabetes mellitus outcomes, it may paradoxically confer survival benefits in heart failure patients, leading researchers to investigate the impact of the obesity-diabetes interaction on heart failure outcomes.

Does overweight status improve survival in patients hospitalized for acute heart failure regardless of their diabetes mellitus status?

Key Points

To investigate the impact of the obesity-diabetes mellitus interaction on clinical outcomes and mortality in patients with heart failure.
Analyzed 8,383 heart failure patients from the KorAHF (NCT01389843) and KorHF (NCT04329234) registries.
Categorized patients into four groups based on body mass index and diabetes status: overweight non-diabetic (31%), overweight diabetic (19%), lean non-diabetic (35%), and lean diabetic (15%).
Evaluated in-hospital mortality and one-year all-cause mortality using multivariable logistic regression and Cox proportional hazards regression models.
One-year all-cause mortality was 9.3% in overweight non-diabetic, 12.7% in overweight diabetic, 16.4% in lean non-diabetic, and 20.7% in lean diabetic patients (P < 0.01).
Overweight diabetic patients had a significantly lower one-year mortality risk than lean diabetic patients after multivariable adjustment (adjusted HR 0.65, 95% CI 0.53-0.79; P < 0.001), with no significant BMI × DM interaction (P = 0.70).

Study Design

Type

Cohort (n=8,383)

Multicenter

Yes

Structured PICO

Does overweight status improve survival in patients hospitalized for acute heart failure regardless of their diabetes mellitus status?

P

Population

8,383 patients hospitalized for acute heart failure, with a mean age of 68.2 years and 48% female, followed for 1 year to assess the impact of BMI and diabetes on mortality.

E

Exposure

Overweight status (defined as BMI ≥ 23 kg/m2 per Korean Society for the Study of Obesity guidelines), stratified by the presence or absence of diabetes mellitus.

C

Comparator

Lean status (defined as BMI < 23 kg/m2), stratified by the presence or absence of diabetes mellitus.

O

Outcome

In-hospital mortality and one-year post-discharge all-cause mortality.hard clinical

Main Result

Hazard Ratio: 0.65 (95% CI 0.53–0.79)

Absolute Event Rate: 12.7% vs 20.7%

p-value: p=<0.001

Overweight status (BMI ≥ 23 kg/m2) is associated with lower one-year mortality in patients hospitalized for acute heart failure, confirming the obesity paradox regardless of concurrent diabetes mellitus.

Limitations

Retrospective design cannot establish causality
Use of two national registries from different time periods may introduce confounding
Relatively low mean BMI and limited proportion of patients at BMI extremes restricts generalizability
Lack of detailed data on cardiorespiratory fitness and body composition, including sarcopenia
Outcome data limited to 1 year
Missing detailed information on diabetes treatment and glycemic control (HbA1c missing in 76.6%)
BMI assessed at hospital admission may be affected by fluid retention, leading to misclassification
Did not account for weight-modifying therapies such as SGLT2 inhibitors or GLP-1 receptor agonists
Observational design cannot prove causality
Potential reverse causality (lower body weight reflecting advanced heart failure, cardiac cachexia, malnutrition, or frailty)
Collider stratification bias
BMI is an imperfect surrogate for body composition and cannot distinguish adiposity from lean body mass
Lack of longitudinal weight trajectories, nutritional status, and skeletal muscle mass data
Findings in a Korean cohort with a lower BMI threshold may not extrapolate to non-Asian populations

Implication

Overweight status should not change weight management in acute HF; supports obesity paradox across diabetes status but remains hypothesis-generating.

Abstract

BACKGROUND: Both diabetes mellitus (DM) and obesity are established risk factors for heart failure (HF). While obesity worsens DM outcomes, it may paradoxically confer survival benefits in HF patients. This study investigated the impact of obesity-DM interaction on clinical outcomes in HF. METHODS AND RESULTS: ), 34.0% had DM. Patients were categorized as overweight non-diabetic (31%), overweight diabetic (19%), lean non-diabetic (35%), and lean diabetic (15%). Lean diabetic patients had the worst baseline characteristics and outcomes, while overweight non-diabetic patients had the most favorable profile. In this retrospective analysis, after multivariable adjustment, overweight diabetic patients had a significantly lower one-year mortality risk than lean diabetic patients (adjusted HR 0.65, 95% CI 0.53-0.79; P < 0.001), as did overweight non-diabetic patients. The association between overweight status and in-hospital mortality was attenuated and no longer statistically significant after adjustment (overweight diabetic: adjusted OR 0.68, 95% CI 0.45-1.03, P = 0.069). No significant BMI × DM interaction was observed. CONCLUSIONS: Overweight status was associated with better prognosis in HF patients regardless of DM status, confirming the obesity paradox in both diabetic and non-diabetic HF populations. This obesity paradox was robust for one-year mortality but, after multivariable adjustment, was not independently associated with in-hospital mortality. Given the observational design, these findings should be interpreted as associations rather than evidence of a causal effect. TRIAL REGISTRATION: KorAHF, ClinicalTrials.gov NCT01389843 (propectively registered); KorHF, ClinicalTrials.gov NCT04329234 (prospectively registered).

Discussion

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Cite This Study

Kwon et al. (2026) conducted a cohort in Heart failure (n=8,383). Overweight status (BMI ≥ 23 kg/m2) vs. Lean status (BMI < 23 kg/m2) was evaluated on One-year post-discharge mortality (overweight diabetic vs lean diabetic) (HR 0.65, 95% CI 0.53-0.79, p=<0.001). Overweight status (BMI ≥ 23 kg/m2) was associated with a significantly lower one-year mortality risk compared to lean status in heart failure patients with diabetes (adjusted HR 0.65) and without diabetes.

synapsesocial.com/papers/6aa27aca58559d80afc7399d https://doi.org/10.1007/s00392-026-03007-0

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Obesity paradox in heart failure with and without diabetes mellitus: a retrospective cohort study

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Obesity paradox in heart failure with and without diabetes mellitus: a retrospective cohort study

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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