CT scans highlight impact of semaglutide on body composition
Blockbuster weight loss drugs like semaglutide don’t just change the ways bodies look on the outside, they modify body composition as well.
Standard clinical measures that gauge weight loss do not paint the full picture of how it affects overall health. Body composition metrics derived from CT scans, on the other hand, can provide greater insight into how losing weight affects the body from a cardiometabolic perspective. Researchers recently detailed exactly how semaglutide affects body composition in new American Journal of Roentgenology research.
“As patients on GLP-1 receptor agonists undergo weight loss (or even weight gain), it is important to understand underlying changes in body composition, including visceral and subcutaneous fat volume, abdominal muscle bulk and quality, bone mineral density, and organ properties (e.g., liver volume and attenuation)," corresponding author Perry J. Pickhardt, MD, from the Departments of Radiology and Medical Physics at the University of Wisconsin School of Medicine & Public Health, and colleagues explained. "Such body composition measures, which cannot be derived from standard clinical assessments (e.g., weight, waist circumference, and BMI), serve as biomarkers for cardiometabolic disease, frailty, and mortality risk.”
For the study, researchers analyzed the abdominal CT scans of 241 patients on semaglutide who had imaging available from both five years before and after going on the medication. The team applied an automated suite of validated AI body composition tools to the scans to quantify measures of visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) area, skeletal muscle area and attenuation, intermuscular adipose tissue (IMAT) area, liver volume and attenuation, and trabecular bone mineral density (BMD). These measures were also compared alongside weight loss and gain among the group.
In the group that lost weight, pre-semaglutide versus post-semaglutide scans showed decreases in VAT area, SAT area, muscle area and liver volume, and an increase in liver attenuation. In contrast, the post-semaglutide scans of the weight gain group showed increased VAT area, SAT area and IMAT area, and decreases in muscle attenuation.
In the weight loss group, all shifts in body composition were positive and benefited cardiometabolic health. These metrics offer a fuller picture of the impact of the GLP-1 agonist class of drugs, the group noted.
“Prior studies of GLP-1 agonist treatment have focused on patient outcomes determined by clinical anthropometric data such as weight and waist circumference. Such outcomes do not capture potentially important tissue-specific changes as can be assessed by CT," the added.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.