TOPLINE

An imaging-derived measure, the sarcopenic obesity index, predicted heart failure, cardiovascular death, and all-cause mortality better than traditional body composition measures such as BMI and waist-based ratios, capturing the combined burden of excess adiposity and low muscle mass.

METHODOLOGY

• Researchers used a deep learning algorithm and developed a novel imaging-based sarcopenic obesity index by combining body weight with three-dimensional measurements of pectoralis major muscle mass from 55,768 cardiac MRI scans in the UK Biobank.
• They used this index to determine its association with prognostic markers of cardiac structure and function as well as cardiovascular and mortality outcomes during a median follow-up of 4.18 years. Cardiovascular outcomes were measured as time to incident cardiovascular events, and mortality outcomes were measured as time to death.
• The development dataset included cardiac MRI axial stacks of the pectoralis major muscle from 200 manually segmented cases, with 150 used for training and 50 independent cases for validation.
• Researchers performed genetic analyses to identify genes linked to sarcopenic obesity and adverse cardiac remodeling and then confirmed the activity of those genes in human muscle samples using transcriptomic analyses.

TAKEAWAY

• Each 1-SD increase in the sarcopenic obesity index was associated with adverse cardiac remodeling on imaging, including lower left ventricular mass, a higher left ventricular mass-to-volume ratio, and higher native T1 values suggestive of diffuse myocardial fibrosis.
• A higher sarcopenic obesity index was associated with a 31% higher risk for incident heart failure (hazard ratio [HR], 1.31), a 51% higher risk for cardiovascular death (hazard ratio [HR], 1.51), and a 37% higher risk for all-cause mortality (HR, 1.37; P < .001 for all).
• The sarcopenic obesity index outperformed BMI, the waist-to-hip ratio, and the waist-to-height ratio in predicting heart failure and cardiovascular and all-cause deaths. The index improved the Harrell C-statistic by approximately 0.005 for heart failure and 0.008-0.009 for mortality outcomes.
• Genetic analyses identified 16 sarcopenic obesity loci, including several overlapping genes linked to heart failure and cardiomyopathy. Transcriptomic analyses revealed that most sarcopenic obesity-linked genes were disproportionately regulated during muscle atrophy.

IN PRACTICE

“Observational, genomic, and transcriptomic analyses performed in this work may aid in incorporating cross-sectional imaging-derived assessment of sarcopenic obesity into clinical risk assessment, stratification, and identification of individuals for targeted intervention,” the researchers wrote.

SOURCE

The study was led by Mihir M. Sanghvi, MBBS, PhD, of the William Harvey Research Institute, National Institute for Health and Care Research Barts Biomedical Research Centre, Queen Mary University of London, England. It was published online on July 1 in JACC.

LIMITATIONS

The observational study design could not exclude residual confounding. Researchers could not differentiate outcomes based on heart failure subtypes. The predominantly White population of the UK Biobank limited generalizability of the findings.

DISCLOSURES

The authors disclosed that the study was conducted in the absence of any commercial or financial relationships that could be construed as potential conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.