Body habitus in heart failure: understanding the mechanisms and clinical significance of the obesity paradox

Association between Triglyceride-Glucose Index and risk of all-cause and cardiovascular mortality in adults with prior cardiovascular disease: a cohort study using data from the US National Health and Nutrition Examination Survey, 2007-2018

OBJECTIVE

The association between the Triglyceride-Glucose (TyG) Index and mortality rates in patients with cardiovascular disease (CVD) remains unclear. This study investigates the association between the TyG index and the incidence of all-cause and CVD-specific mortality among individuals with a history of CVD.

DESIGN

Population-based cohort study.

SETTING

Data were sourced from the US National Health and Nutrition Examination Survey (2007-2018) and linked mortality data, with follow-up continuing until 31 December 2019.

PARTICIPANTS

The study population comprised 3422 individuals aged 20 years or older with a documented history of CVD.

OUTCOME MEASURES

We examined the association between the TyG index and the risk of all-cause and cardiovascular mortality.

RESULTS

Over a median follow-up of 5.79 years, 1030 deaths occurred, including 339 due to CVD. Cox regression analysis, adjusted for multiple confounders, showed that individuals in the highest TyG index quartile, compared with those in the lowest, had HRs of 0.76 (95% CI: 0.60 to 0.96) for all-cause mortality and 0.58 (95% CI: 0.39 to 0.89) for CVD mortality. There was a significant inverse relationship between higher TyG index levels and lower mortality risks. For each unit increase in the TyG index, the adjusted HRs for all-cause and CVD mortality decreased by 18% (HR 0.82; 95% CI: 0.71 to 0.94) and 27% (HR 0.73; 95% CI: 0.57 to 0.92), respectively.

CONCLUSIONS

TyG index values are negatively associated with all-cause and CVD mortality risks among individuals with previous CVD. Further interventional studies are needed to clarify the impact of TyG levels on cardiovascular health.

Association between triglyceride glucose-body mass index and long-term adverse outcomes of heart failure patients with coronary heart disease

BACKGROUND

The triglyceride glucose-body mass index (TyG-BMI) is recognized as a reliable surrogate for evaluating insulin resistance and an effective predictor of cardiovascular disease. However, the link between TyG-BMI index and adverse outcomes in heart failure (HF) patients remains unclear. This study examines the correlation of the TyG-BMI index with long-term adverse outcomes in HF patients with coronary heart disease (CHD).

METHODS

This single-center, prospective cohort study included 823 HF patients with CHD. The TyG-BMI index was calculated as follows: ln [fasting triglyceride (mg/dL) × fasting blood glucose (mg/dL)/2] × BMI. To explore the association between the TyG-BMI index and the occurrences of all-cause mortality and HF rehospitalization, we utilized multivariate Cox regression models and restricted cubic splines with threshold analysis.

RESULTS

Over a follow-up period of 9.4 years, 425 patients died, and 484 were rehospitalized due to HF. Threshold analysis revealed a significant reverse "J"-shaped relationship between the TyG-BMI index and all-cause mortality, indicating a decreased risk of all-cause mortality with higher TyG-BMI index values below 240.0 (adjusted model: HR 0.90, 95% CI 0.86-0.93; Log-likelihood ratio p = 0.003). A distinct "U"-shaped nonlinear relationship was observed with HF rehospitalization, with the inflection point at 228.56 (adjusted model: below: HR 0.95, 95% CI 0.91-0.98; above: HR 1.08, 95% CI 1.03-1.13; Log-likelihood ratio p < 0.001).

CONCLUSIONS

This study reveals a nonlinear association between the TyG-BMI index and both all-cause mortality and HF rehospitalization in HF patients with CHD, positioning the TyG-BMI index as a significant prognostic marker in this population.

Current Perspectives: Obesity and Neurodegeneration - Links and Risks

Obesity is increasing in prevalence across all age groups. Long-term obesity can lead to the development of metabolic and cardiovascular diseases through its effects on adipose, skeletal muscle, and liver tissue. Pathological mechanisms associated with obesity include immune response and inflammation as well as oxidative stress and consequent endothelial and mitochondrial dysfunction. Recent evidence links obesity to diminished brain health and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Both AD and PD are associated with insulin resistance, an underlying syndrome of obesity. Despite these links, causative mechanism(s) resulting in neurodegenerative disease remain unclear. This review discusses relationships between obesity, AD, and PD, including clinical and preclinical findings. The review then briefly explores nonpharmacological directions for intervention.

Obesity Paradox among Heart Failure with Reduced Ejection Fraction Patients: A Retrospective Cohort Study

Background and Objectives: There is consensus on the negative effects of obesity on the development of heart failure. However, several studies have suggested that obesity may have paradoxical survival benefits in heart failure patients. Therefore, the aim of this study is to investigate whether the obesity paradox exists in heart failure with reduced ejection fraction (HFrEF) patients in Jordan. Materials and Methods: In this retrospective cohort study, data were retrieved from electronic hospital records of heart failure patients admitted to King Abdullah University Hospital between January 2010 and January 2020. Patients were divided into five BMI (kg/m2) subgroups: (1) Less than 25.0, (2) Overweight 25.0−29.9, (3) Obese Class I 30.0−34.9, (4) Obese Class II 35.0−39.9, and (5) Obese Class III ≥40.0. Changes in patients’ clinical and echocardiographic parameters over one year were analyzed. Results: Data of a total of 297 patients were analyzed to determine the effect of obesity on heart failure. The mean age was 64.6 ± 12.4 years, and most patients (65.7%) were male. Among several co-morbidities, diabetes mellitus and hypertension were the most common and were present in 81.8% and 81.1% of patients, respectively. Over all patients, there was no significant change in EF after 1 year compared to baseline. However, only patients in the Obese Class I group had a statistically significant improvement in EF of 38.0 ± 9.81% vs. 34.8 ± 6.35% (p = 0.004) after 1 year. Importantly, among non-diabetic individuals, only Obese Class I patients had a significant (p < 0.001) increase in EF after 1 year compared to other BMI subgroups, a feature that was not observed among patients with diabetes. On the other hand, only Obese Class I patients with hypertension had a significant improvement (p < 0.05) in EF after 1 year compared to other BMI subgroups, a feature that was not observed among patients without hypertension. Conclusions: Our study demonstrates an inverted U-shaped relationship between BMI and EF such that patients with mild obesity (i.e., Obese Class I) had significant improvement in EF compared to those having a lower and higher BMI. We, therefore, suggest the existence of the obesity paradox among HFrEF patients in Jordan.

Baseline Characteristics Associated with Good Collateral Status Using Hypoperfusion Index as an Outcome

Up to 30% of ischemic stroke cases are due to large vessel occlusion (LVO), causing significant morbidity. Studies have shown that the collateral circulation of patients with acute ischemic stroke (AIS) secondary to LVO can predict their clinical and radiological outcomes. The aim of this study is to identify baseline patient characteristics that can help predict the collateral status of these patients for improved triage. In this IRB approved retrospective study, consecutive patients presenting with AIS secondary to anterior circulation LVO were identified between September 2019 and August 2021. The baseline patient characteristics, laboratory values, imaging features and outcomes were collected using a manual chart review. From the 181 consecutive patients initially reviewed, 54 were confirmed with a clinical diagnosis of AIS and anterior circulation LVO. In patients with poor collateral status, the body mass index (BMI) was found to be significantly lower compared to those with good collateral status (26.4 ± 5.6 vs. 31.7 ± 12.3; p = 0.045). BMI of >35 kg/m2 was found to predict the presence of good collateral status. Age was found to be significantly higher (70.5 ± 9.6 vs. 58.9 ± 15.6; p = 0.034) in patients with poor collateral status and M1 strokes associated with older age and BMI.

The Association of Body Mass Index With Mortality Among Pulmonary Hypertension Patients: A Systematic Review and Meta-Analysis of Cohort Studies

Objective

To run a systematic review and meta-analysis of related studies on body mass index (BMI) and the risk of death among pulmonary hypertension (PH) patients, as well as, to shed light on the shape and strength of the dose-response association.

Methods

Studies published up to Jun 2021 in scientific databases such as Scopus, and PubMed as well as Google Scholar were searched. Cohort studies that reported risk estimates for at least two categories of BMI or per certain increase in BMI in relation to mortality in PH patients were included. Summary relative risks were determined with random effects models. Non-linear relationship was discovered with dose-response analysis.

Results

All in all, 15 cohort studies were selected. The number of participants was 127,215 out of which 73,999 were reported dead. The summary RR for mortality per a 5-unit increment in BMI was 0.83 (95% confidence interval 0.77–0.89; I² = 75.6%, n = 9) among PH patients. There was a non-linear dose-response relation between BMI and mortality in PH patients (P_{non−linearity} < 0.001), with the lowest risk being at BMI 32–38 kg/m².

Conclusion

Higher BMI is related to decreased risk of mortality among PH patients and the lowest point of the curve was seen at BMI 32–38.

Congestive Heart Failure Exhibited Higher BMI With Lower Energy Intake and Lower Physical Activity Level: Data From the National Health and Examination Nutrition Survey

Background: Despite that nutritional deficiency existed in congestive heart failure (CHF), there is a large amount of CHF patients suffering from obesity. This study aimed to identify the differences for increased BMI or obesity in CHF patients.

Methods: This cross-sectional study included adults from the National Health and Nutrition Examination Survey 2007–2016. Differences were compared between CHF participants vs. non-CHF participants, and BMI ≥ 30 kg/m² vs. BMI < 30 kg/m² CHF participants.

Results: CHF participants were with higher BMI, lower energy and macronutrient intake, lower physical activity level and longer rest time, and lower hematocrit and hemoglobin level (all P < 0.05) than non-CHF participants. The prevalence of BMI ≥ 30 kg/m² in participants with CHF was 53.48%. There was no significant difference observed in energy and macronutrient intake between CHF participants with BMI ≥ 30 kg/m² or <30 kg/m². The water intake (P = 0.032), sedentary time (P = 0.002), and hematocrit (P = 0.028) were significantly different between CHF with BMI ≥ 30 kg/m² and with <30 kg/m².

Conclusion: Compared with non-CHF participants, CHF participants exhibited higher BMI with lower energy and macronutrient intake, lower physical activity level, longer rest time, and hemodilution with lower hematocrit and hemoglobin level. Among CHF participants with BMI ≥ 30 kg/m², higher sedentary time and hematocrit were observed.

Obesity and Stroke: Does the Paradox Apply for Stroke?

Historically, obesity has been identified as one of the most important risk factors for developing cardiovascular diseases including stroke; however, a theory called "The Obesity Paradox" has been recently considered. The paradoxical theory is that obese or overweight patients (according to body mass index score) can have better outcomes compared to leaner or malnourished patients. The paradox was initially discovered in patients with heart failure. The purpose of this manuscript was to investigate whether this paradox also applies to stroke patients, according to information available in the current literature.

Implications of obesity across the heart failure continuum

The obesity paradox, which suggests a survival advantage for the obese in heart failure (HF) has sparked debate in the medical community. Studies demonstrate a survival advantage in obese patients with HF, including those with advanced HF requiring continuous inotropic support for palliation or disease modifying therapy with a left ventricular assist device (LVAD) or heart transplantation (HT). Importantly, the obesity paradox is affected by the level of cardiorespiratory fitness (CRF). It is now recommended that HF patients with body mass index ≥35 kg/m² achieve at least 5-10% weight loss, in order to improve symptoms and cardiac function, though more robust data are urgently needed. CRF may be the single best predictor of overall health and small improvements in fitness levels may lead to improved outcomes in HF. In addition to implications of obesity in chronic HF, we also discuss management of obese patients with advanced HF and their implications for therapies such as LVAD implantation and HT.

Obesity paradox in cardiovascular disease: where do we stand?

Obesity is associated with an increased risk of developing cardiovascular disease (CVD), particularly heart failure (HF) and coronary heart disease (CHD). The mechanisms through which obesity increases CVD risk involve changes in body composition that can affect hemodynamics and alters heart structure. Pro-inflammatory cytokines produced by the adipose tissue itself which can induce cardiac dysfunction and can promote the formation of atherosclerotic plaques. When obesity and HF or CHD coexist, individuals with class I obesity present a more favorable prognosis compared to individuals who are normal or underweight. This phenomenon has been termed the “obesity paradox.” Obesity is defined as an excess fat mass (FM), but individuals with obesity typically also present with an increased amount of lean mass (LM). The increase in LM may explain part of the obesity paradox as it is associated with improved cardiorespiratory fitness (CRF), a major determinant of clinical outcomes in the general population, but particularly in those with CVD, including HF. While increased LM is a stronger prognosticator in HF compared to FM, in patients with CHD excess FM can exert protective effects particularly when not associated with increased systemic inflammation. In the present review, we discuss the mechanisms through which obesity may increase the risk for CVD, and how it may exert protective effects in the setting of established CVD, with a focus on body composition. We also highlight the importance of measuring or estimating CRF, including body composition-adjusted measures of CRF (ie, lean peak oxygen consumption) for an improved risk status stratification in patients with CVD and finally, we discuss the potential non-pharmacologic therapeutics, such as exercise training and dietary interventions, aimed at improving CRF and perhaps clinical outcomes.

Obesity Paradox in Aging: From Prevalence to Pathophysiology

Recent advances in medical technology and health care have greatly improved the management for chronic diseases and prolonged human lifespan. Unfortunately, increased lifespan and the aging population impose a major challenge on the ever-rising prevalence of chronic diseases, in particular cardiometabolic stress associated with the pandemic obesity in our modern society. Although overweight and obesity are associated with incident cardiovascular diseases (CVD), including heart failure (HF), it paradoxically leads to a more favorable prognosis in patients with chronic HF, a phenomenon commonly defined as "obesity paradox". Numerous population-based and clinical studies have suggested possible explanations such as better metabolic reserve, smoking and disease-associated weight loss for obesity paradox. Recent evidence noticed a shift in obesity paradox with aging. While some studies have reported a more pronounced "obesity paradox" in the older patients, others have seen diminished cardiac benefits with overweight and obesity in the elderly patients with CVD. These findings suggested that a complex relationship among aging, metabolism, and HF severity/chronicity, which may explain the shift in obesity paradox in the elderly. Aging negatively affects body metabolism and cardiac function although its precise impact on obesity paradox remains elusive. To develop new strategies for cardiovascular health in the elderly, it is imperative to understand the precise role for aging on obesity-related CVD.

Relation Between Obesity and Survival in Patients Hospitalized for Pulmonary Arterial Hypertension (from a Nationwide Inpatient Sample Database 2003 to 2011)

There have been numerous studies reporting lower mortality rates in obese patients with various cardiovascular disorders than in nonobese patients, a phenomenon known as the "obesity paradox." Limited data exist regarding the effect of obesity on prognosis in patients with pulmonary arterial hypertension (PAH). We used the National Inpatient Sample database for years 2003 to 2011 to identify all patient hospitalizations aged ≥18 years with a primary diagnosis of PAH. Patients with a diagnosis of obesity were identified using Elixhauser co-morbidity measure provided in Nationwide Inpatient Sample database, based on International Classification of Diseases, Ninth Revision, Clinical Modification, codes and the diagnosis-related groups. Multivariable logistic regression was used to compare in-hospital mortality between obese and nonobese patients with PAH. Of the 18,450 patients with a primary diagnosis of PAH, 14.7% were obese. Obese patients with PAH were younger, more often women, and more often black compared with nonobese white patients. After risk adjustment for demographics, hospital characteristics, and baseline co-morbidities, obese patients with PAH had lower observed in-hospital mortality compared with nonobese patients with PAH (3.5% vs 8.1%; adjusted odds ratio 0.66, 95% confidence interval 0.51 to 0.85, p = 0.001). In conclusion, from a 9-year nationwide cohort of patients with PAH, we observed significantly lower risk-adjusted in-hospital mortality in obese patients compared with nonobese patients.

Triceps and Subscapular Skinfold in Men Aged 40-65 and Dementia Prevalence 36 Years Later

BACKGROUND

The relationship of obesity with risk for dementia is complex and may change with age.

OBJECTIVE

To analyze the relationship between measures of obesity at age 40-65 and dementia prevalence in survivors 36 years later.

METHODS

Obesity-related measures of triceps and subscapular skinfold thickness were assessed in 1963 in n = 9,760 men aged 40-65 participating in the Israel Ischemic Heart Disease study. Cognitive evaluation and assessment of dementia prevalence were performed in n = 1,643 participants of the original cohort who survived until 1999/2000 (age ≥76 years) and had anthropometric measures in 1963.

RESULTS

Age-adjusted prevalence of dementia in survivors in 1999/2000 by baseline triceps skinfold quintile was 20.5%, 21.2%, 17.6%, 15.6%, and 14.5%, respectively, from lowest to highest (p = 0.006 in trend test). Using logistic regression, a 6-mm increment of triceps skinfold was associated with an age and BMI-adjusted odds ratio of 0.81 (95% CI, 0.70-0.94) for dementia prevalence among survivors. Age-adjusted risk for dementia by subscapular skinfold quintile demonstrated 20.5%, 17.1%, 15.7%, 19.4%, and 18.1%, respectively, in groups of subjects by subscapular skinfold quintile from lowest to highest (p = 0.6 in trend test).

CONCLUSIONS

Lower triceps skinfold at age 40-65, reflecting diminished peripheral fat, was associated with higher dementia prevalence in late life, potentially suggesting a protective role of peripheral fat to brain health.

Obesity and Heart Failure: Focus on the Obesity Paradox

The escalating prevalence of obesity has been linked to substantial increases in both metabolic and cardiovascular disease. Nevertheless, the direct effects of obesity on cardiovascular health and function require further exploration. In particular, the relationship between obesity and cardiac function has received intense scrutiny. Although obesity increases the risk for development of heart failure (HF), it appears to exert a protective effect in patients in whom HF has already been diagnosed (the "obesity paradox"). The protective effects of obesity in patients with previously diagnosed HF are the focus of particularly intense research. Several explanations have been proposed, but most studies are limited by the use of body mass index to classify obesity. Because body mass index does not distinguish between fat mass, fat-free mass, and lean mass, individuals with similar body mass indices may have vastly different body composition. This article discusses the roles of body composition, diet, cardiorespiratory fitness, and weight loss in the development of cardiac dysfunction and HF and the potential protective role that body composition compartments might play in improving HF prognosis. Based on an intensive literature search (Pubmed, Google Scholar) and critical review of the literature, we also discuss how a multidisciplinary approach including a nutritional intervention targeted to reduce systemic inflammation and lean mass-targeted exercise training could potentially exert beneficial effects for patients with HF.