Diagnostic performance of weight loss to predict body fatness improvement in cardiac rehabilitation patients

Recipient race modifies the association between obesity and long-term graft outcomes after kidney transplantation

Donor and recipient obesity (defined using body mass index [BMI]) are associated with worse outcomes after kidney transplant (KT). In adult KT recipients identified using the Scientific Registry of Transplant Recipients (2000-2017), we examined the modifying effect of recipient race on recipient obesity (BMI > 30 kg/m2) and combined donor and recipient (DR) obesity pairing, with death-censored graft loss (DCGL), all-cause graft loss (ACGL), and short-term graft outcomes using multivariable Cox proportional hazards models and logistic regression. Obesity was associated with a higher risk of DCGL in White (adjusted hazard ratio [aHR], 1.29; 95% CI, 1.25-1.35) than Black (aHR, 1.13; 95% CI, 1.08-1.19) recipients. White, but not Black, recipients with obesity were at higher risk for ACGL (aHR, 1.08; 95% CI, 1.05-1.11, for White recipients; aHR, 0.99; 95% CI, 0.95-1.02, for Black recipients). Relative to nonobese DR, White recipients with combined DR obesity experienced more DCGL (aHR, 1.38; 95% CI, 1.29-1.47 for White; aHR, 1.19; 95% CI, 1.10-1.29 for Black) and ACGL (aHR, 1.12; 95% CI, 1.07-1.17 for White; aHR, 1.00; 95% CI, 0.94-1.07 for Black) than Black recipients. Short-term obesity risk was similar irrespective of race. An elevated BMI differentially affects long-term outcomes in Black and White KT recipients; uniform BMI thresholds to define transplant eligibility are likely inappropriate.

Challenges in Cardiovascular Evaluation and Management of Obese Patients: JACC State-of-the-Art Review

Many unique clinical challenges accompany the diagnosis and treatment of cardiovascular disease (CVD) in people living with overweight/obesity. Similarly, physicians encounter numerous complicating factors when managing obesity among people with CVD. Diagnostic accuracy in CVD medicine can be hampered by the presence of obesity, and pharmacological treatments or cardiac procedures require careful adjustment to optimize efficacy. The obesity paradox concept remains a source of confusion within the clinical community that may cause important risk factors to go unaddressed, and body mass index is a misleading measure that cannot account for body composition (eg, lean mass). Lifestyle modifications that support weight loss require long-term commitment, but cardiac rehabilitation programs represent a potential opportunity for structured interventions, and bariatric surgery may reduce CVD risk factors in obesity and CVD. This review examines the key issues and considerations for physicians involved in the management of concurrent obesity and CVD.

Obesity and Cardiovascular Disease: A Scientific Statement From the American Heart Association

The global obesity epidemic is well established, with increases in obesity prevalence for most countries since the 1980s. Obesity contributes directly to incident cardiovascular risk factors, including dyslipidemia, type 2 diabetes, hypertension, and sleep disorders. Obesity also leads to the development of cardiovascular disease and cardiovascular disease mortality independently of other cardiovascular risk factors. More recent data highlight abdominal obesity, as determined by waist circumference, as a cardiovascular disease risk marker that is independent of body mass index. There have also been significant advances in imaging modalities for characterizing body composition, including visceral adiposity. Studies that quantify fat depots, including ectopic fat, support excess visceral adiposity as an independent indicator of poor cardiovascular outcomes. Lifestyle modification and subsequent weight loss improve both metabolic syndrome and associated systemic inflammation and endothelial dysfunction. However, clinical trials of medical weight loss have not demonstrated a reduction in coronary artery disease rates. In contrast, prospective studies comparing patients undergoing bariatric surgery with nonsurgical patients with obesity have shown reduced coronary artery disease risk with surgery. In this statement, we summarize the impact of obesity on the diagnosis, clinical management, and outcomes of atherosclerotic cardiovascular disease, heart failure, and arrhythmias, especially sudden cardiac death and atrial fibrillation. In particular, we examine the influence of obesity on noninvasive and invasive diagnostic procedures for coronary artery disease. Moreover, we review the impact of obesity on cardiac function and outcomes related to heart failure with reduced and preserved ejection fraction. Finally, we describe the effects of lifestyle and surgical weight loss interventions on outcomes related to coronary artery disease, heart failure, and atrial fibrillation.

Obesity in coronary heart disease: An unaddressed behavioral risk factor

Obesity is an independent risk factor for the development and progression of coronary heart disease (CHD). Over 80% of patients with CHD are overweight or obese. While obesity is often considered a relatively "minor" CHD risk factor, weight loss is a broadly effective risk-factor intervention. Weight loss can profoundly influence a number of "major" risk factors including: hypertension, dyslipidemia and insulin resistance/type 2 diabetes mellitus. Despite its prominence as a risk factor most cardiac rehabilitation (CR) programs do not have a specific, targeted intervention to assist patients with weight loss. Consequently, the weight loss that occurs during CR is quite small and unlikely to appreciably alter risk factors. Relying on CR associated exercise as a sole intervention is an ineffective strategy to promote weight loss. There is evidence, however, that behavioral weight loss (BWL) interventions can be effectively employed in the CR setting. In contrast to programs that do not offer a targeted intervention, studies show that participants in CR-related BWL programs lose significantly more weight. The additional weight loss from the BWL intervention is associated with greater improvements in insulin sensitivity and other components of the metabolic syndrome such as hypertension and lipid abnormalities. As a means of maximizing CHD risk factor reduction CR programs need to incorporate BWL programs as a standard programming for overweight/obese patients.

Diagnostic performance of skinfold method to identify obesity as measured by air displacement plethysmography in cardiac rehabilitation

PURPOSE

To assess the diagnostic performance of the skinfold (SKF) method to detect obesity in patients enrolled in an outpatient cardiac rehabilitation (CR) program.

METHODS

This study involves outpatients attending a phase II CR program who underwent air displacement plethysmography (ADP) to assess body composition. We measured body fat percentage (BF%), using a 3-site SKF method calculated through the Jackson-Pollock equation utilizing a Harpenden caliper. Air displacement plethysmography calculated BF% using a bicompartmental model, deriving the body composition after the direct calculation of body density (BD), using the Siri equation [(BF% = 495/BD) - 450]. We calculated the diagnostic performance of SKF to detect obesity, utilizing a BF% cutoff of ≥35% for women and ≥25% for men determined by SKF and ADP to define obesity.

RESULTS

Our sample (n = 310) was 80% men, 60.2 ± 11 years of age, had a mean weight of 89.88 ± 17.96 kg, height 173.38 ± 8.68 cm, body mass index (BMI) 29.78 ± 5.01 kg/m, waist circumference 100.55 ± 14.38 cm, and waist-to-hip ratio of 0.96 ± 0.09. The evaluation of the diagnostic performance of SKF to detect obesity showed a sensitivity of 57%, specificity of 93%, a positive predictive value of 97%, and a negative predictive value of 33%. These values were not different from the diagnostic performance of BMI to detect obesity as defined by BF%. SKF and BMI misclassified 43% and 49% of obese patients as nonobese, respectively.

CONCLUSION

Our findings underscore the limitation of using SKF to assess body fatness in the CR setting.

The prognostic importance of weight loss in coronary artery disease: a systematic review and meta-analysis

OBJECTIVE

To assess the prognostic impact of weight loss on clinical outcomes in patients with coronary artery disease (CAD).

METHODS

We performed a systematic review and meta-analysis of the prognostic effects of weight loss in patients with CAD on a composite outcome of all-cause mortality, cardiovascular mortality, and major adverse cardiac events considering studies published between January 1, 1964, and August 8, 2013. We considered weight loss "intentional" when it occurred in the presence of programmed therapeutic lifestyle changes and "observational" when no such intervention was specified.

RESULTS

We searched 1218 abstracts, of which 12 studies with 14 cohorts met the inclusion criteria. A total of 35,335 patients (mean age, 64 years; 72% male; body mass index [BMI], 30; 3.2 years of follow-up) were included. Overall, weight loss was associated with a greater risk of the composite outcome (relative risk [RR], 1.30; 95% CI, 1.00-1.69; P=.05). However, heterogeneity was high (I(2)=90%) and was substantially explained by weight loss intentionality. Presumed intentional weight loss (4 cohorts) was associated with improved outcomes (RR, 0.67; 95% CI, 0.56-0.80; P<.001), whereas observational weight loss (10 cohorts) was associated with worsened outcomes (RR, 1.62; 95% CI, 1.26-2.08; P<.001; interaction P<.001).

CONCLUSION

Whereas observational weight loss is associated with increased adverse cardiovascular events, intentional weight loss is associated with lower clinical events. These results suggest that the underlying mechanism of weight loss (ie, intentional or unintentional) affects its impact on subsequent risk in persons with known CAD.