Alban De Schutter

Obesity and Prevalence of Cardiovascular Diseases and Prognosis—The Obesity Paradox Updated

The prevalence and severity of obesity have increased in the United States and most of the Westernized World over recent decades, reaching worldwide epidemics. Since obesity worsens most of the cardiovascular disease (CVD) risk factors, not surprisingly, most CVDs, including hypertension, coronary heart disease, heart failure, and atrial fibrillation, are all increased in the setting of obesity. However, many studies and meta-analyses have demonstrated an obesity paradox with regards to prognosis in CVD patients, with often the overweight and mildly obese having a better prognosis than do their leaner counterparts with the same CVD. The implication for fitness to markedly alter the relationship between adiposity and prognosis and the potential impact of weight loss, in light of the obesity paradox, are all reviewed.

The impact of obesity on risk factors and prevalence and prognosis of coronary heart disease-the obesity paradox

Obesity is associated with a host of cardiovascular risk factors and its prevalence is rising rapidly. Despite strong evidence that obesity predisposes to the development and progression of coronary heart disease (CHD), numerous studies have shown an inverse relationship between various measures of obesity (most commonly body mass index) and outcomes in established CHD. In this article we review the evidence surrounding the ≪obesity paradox≫ in the secondary care of CHD patients and the CHD presentations where a paradox has been found. Finally we discuss the impact of cardiorespiratory fitness and a number of mechanisms which may offer potential explanations for this puzzling phenomenon.

Body Composition and Coronary Heart Disease Mortality—An Obesity or a Lean Paradox?

OBJECTIVE To determine the combined effects of body mass index (BMI) and body fat (BF) on prognosis in coronary heart disease (CHD) to better understand the obesity paradox. PATIENTS AND METHODS We studied 581 patients with CHD between January 1, 2000, and July 31, 2005, who were divided into low (<25) and high BMI (≥25), as well as low (≤25% men and ≤35% women) and high BF (>25% in men and >35% in women). Four groups were analyzed by total mortality during the 3-year follow-up by National Death Index: low BF/low BMI (n=119), high BF/low BMI (n=26), low BF/high BMI (n=125), and high BF/high BMI (n=311). RESULTS During the 3-year follow-up, mortality was highest in the low BF/low BMI group (11%), which was significantly (P<.001) higher than that in the other 3 groups (3.9%, 3.2%, and 2.6%, respectively); using the high BF/high BMI group as a reference, the low BF/low BMI group had a 4.24-fold increase in mortality (confidence interval [CI], 1.76-10.23; P=.001). In multivariate logistic regression for mortality, when entered individually, both high BMI (odds ratio [OR], 0.79; CI, 0.69-0.90) and high BF (OR, 0.89; CI, 0.82-0.95) as continuous variables were independent predictors of better survival, whereas low BMI (OR, 3.60; CI, 1.37-9.47) and low BF (OR, 3.52; CI, 1.34-9.23) as categorical variables were independent predictors of higher mortality. CONCLUSION Although both low BF and low BMI are independent predictors of mortality in patients with CHD, only patients with combined low BF/low BMI appear to be at particularly high risk of mortality during follow-up. Studies are needed to determine optimal body composition in the secondary prevention of CHD.

Update on Obesity and Obesity Paradox in Heart Failure

Obesity has reached epidemic proportions in most of the Westernized world. Overweightness and obesity adversely impact cardiac structure and function, including on both the right and, especially, left sides of the heart, with adverse affects on systolic and, especially, diastolic ventricular function. Therefore, it is not surprising that obesity markedly increases the prevalence of heart failure (HF). Nevertheless, many studies have documented an obesity paradox in large cohorts with HF, where overweight and obese have a better prognosis, at least in the short-term, compared with lean HF patients. Although weight loss clearly improves cardiac structure and function and reduces symptoms in HF, there are no large studies on the impact of weight loss on clinical events in HF, preventing definitive guidelines on optimal body composition in patients with HF.

Correlation and discrepancies between obesity by body mass index and body fat in patients with coronary heart disease

BACKGROUND: Despite its many shortcomings, body mass index (BMI) is the most widely used screening tool for obesity, in part, because of its practicality. Other more physiologic measurements of obesity are based on body fat (BF). However, the correlation between BMI and BF has not been well-characterized, especially in patients with coronary heart disease (CHD). METHODS: We retrospectively studied 581 patients with CHD following major CHD events, who were divided according to BMI (calculated as weight divided by height squared), based on the World Health Organization standard cutoff points (underweight [<18.5 kg/m2], normal [≥18.5 and <25 kg/m2], overweight [≥25 and <30 kg/m2], and obese [≥30 kg/m2]). Second, the population was divided according to BF, on the basis of the age- and gender-adjusted Gallagher BF classification into underweight, normal, overweight, and obese categories. RESULTS: Body mass index and percent BF correlated significantly (r = 0.60; P < .0001) and classified patients in the same category in about 59% of patients. In approximately 27% of the sample, BMI underestimated BF, while in about 14% of cases BMI overestimated BF. The relationship between BMI and BF was influenced by age, gender, and BMI itself. CONCLUSIONS: Even though a correlation exists between BMI and BF, they frequently classify individuals differently in a population of CHD patients. When defining overweight/obesity, care must be taken when using a crude screening tool such as BMI. While it is not expected for all clinicians to add BF assessments within routine patient assessments, the results of this study may be helpful to guide clinicians and researchers who are considering different aspects of body composition.

Body Composition and Mortality in a Large Cohort With Preserved Ejection Fraction: Untangling the Obesity Paradox

OBJECTIVE To evaluate the effects of body composition as a function of lean mass index (LMI) and body fat (BF) on the correlation between increasing body mass index (BMI; calculated as the weight in kilograms divided by the height in meters squared) and decreasing mortality, which is known as the obesity paradox. PATIENTS AND METHODS We retrospectively assessed 47,866 patients with preserved left ventricular ejection fraction (≥50%). We calculated BF by using the Jackson-Pollock equation and LMI using (1 - BF) × BMI. The population was divided according to the sex-adjusted BMI classification, sex-adjusted LMI classification, and sex-adjusted BF tertiles. The population was analyzed by using multivariate analysis for total mortality over a mean follow-up duration of 3.1 years by using the National Death Index, adjusting for left ventricular ejection fraction, left ventricular mass index, age, sex, and relative wall thickness. RESULTS In the entire population, higher BMI was narrowly associated (hazard ratio [HR], 0.99; P<.001) with lower mortality. The higher LMI group was clearly protective (HR, 0.71; P<.001), whereas BF tertile was associated with lower mortality only if no adjustment was made for LMI (HR, 0.87; P<.001 without LMI; HR, 0.97; P=.23 with LMI). In the lean patients, low BMI was clearly associated with higher mortality (HR, 0.92; P<.001) and lower BF tertile was associated with lower mortality only if no adjustment was made for LMI (HR, 0.80; P<.001 without LMI; HR, 1.01; P=.83 with LMI). The underweight patients stratified by BF seemed to have an increased mortality (HR, 1.91; 95% CI, 1.56-2.34) that was independent of LMI. However, in obese patients, both BMI (HR, 1.03; P<.001) and BF (HR, 1.18; P=.003) were associated with higher mortality, even after adjusting for LMI, which remained protective (HR, 0.57; P<.001) independently of BF. CONCLUSION Body composition could explain the inverse J shape of the mortality curve noted with increasing BMI. Body fat seems to be protective in this cohort only if no adjustment was made for LMI, although being underweight stratified by BF seems to be an independent risk factor. Lean mass index seems to remain protective in obese patients even when BMI is not.

Obesity Paradox, Cachexia, Frailty, and Heart Failure

Overweight and obesity adversely affect cardiovascular (CV) risk factors and CV structure and function, and lead to a marked increase in the risk of developing heart failure (HF). Despite this, an obesity paradox exists, wherein those who are overweight and obese with HF have a better prognosis than their leaner counterparts, and the underweight, frail, and cachectic have a particularly poor prognosis. In light of this, the potential benefits of exercise training and efforts to improve cardiorespiratory fitness, as well as the potential for weight reduction, especially in severely obese patients with HF, are discussed.

Impact of Cardiac Rehabilitation and Exercise Training on Psychological Risk Factors and Subsequent Prognosis in Patients With Cardiovascular Disease

The role of psychological risk factors has been under-recognized in most subspecialties of medicine, as well as in general medicine practices. However, considerable evidence indicates that psychosocial factors are involved in the pathogenesis and progression of cardiovascular disease (CVD). Emerging data from cardiac rehabilitation (CR) settings and CR exercise training (CRET) programs have demonstrated the value of comprehensive CRET to improve psychological functioning and reduce all-cause mortality. Recent evidence also supports the role of CRET and the added value of stress management training in the secondary prevention of CVD.

Obesity paradox and the heart: which indicator of obesity best describes this complex relationship?

Purpose of reviewDespite the detrimental effects of obesity on coronary heart disease (CHD) and heart failure, obesity is found to be paradoxically associated with improved survival in secondary care of CHD and heart failure. This ‘obesity paradox’ is an area of active research, and it might be the result of an inaccurate working definition of obesity, which is traditionally defined in terms of BMI. We reviewed the recent literature on the paradox and examined different anthropomorphic measurements and their association with prognosis in cardiovascular diseases. Recent findingsIn CHD, obesity is associated with improved prognosis when defined by high BMI and body fat, independent of fat-free mass (FFM). High waist circumference seems to be associated with worse prognosis in some studies, but is associated with protection and an obesity paradox in those with poor cardiorespiratory fitness (CRF). In patients with heart failure, BMI, body fat and waist circumference, and possibly FFM, have been associated with improved survival. Despite these findings, intentional weight loss remains protective. In both CHD and heart failure, CRF seems to significantly impact the relationship between adiposity and subsequent prognosis, and an obesity paradox is only present with low CRF. SummaryBody composition, including waist circumference, body fat and FFM have a role in clinical practice. Emphasis should be placed on improving CRF, regardless of weight status. Intentional weight loss, particularly while maintaining FFM, should be encouraged in obese individuals.

Does fitness completely explain the obesity paradox

Theresulthasbeen an adverse impact on many of the major CV andcoronary heart disease (CHD) risk factors includingincreasing levels of arterial pressure, increasing insulinresistance (thus leading to increased prevalence ofmetabolic syndrome and type 2 diabetes mellitus),increasing dyslipidemia (especially increasing triglycer-ides and reducing levels of the cardioprotective high-density lipoprotein cholesterol), and increasing inflam-mation (evidenced by increased C-reactive protein), andalthough sedentary lifestyle may increase the prevalenceof obesity, increases in weight may also beget physicalinactivity. Not surprisingly, obesity increases almost allmajor CV diseases including hypertension, CHD, heartfailure (HF), peripheral arterial disease, and atrial fibrilla-tion. Numerous studies and large meta-analyses have nowclearly demonstrated that overweight and obese patientswith established CV diseases paradoxically have a betterprognosis than do comparable subjects who are lean.Most of the evidence demonstrating this obesityparadox, including the article in this issue of the Ameri-can Heart Journal by Uretsky et al,