Weight-Loss Magnitude, Fat Mass, and Device-Estimated Muscle Mass Loss During Obesity Pharmacotherapy
5 affiliations
- 1Doctoral School of Medicine, “Victor Babes” University of Medicine and Pharmacy, 300041 Timisoara, Romania
- 2Centre for Molecular Research in Nephrology and Vascular Disease, “Victor Babes” University of Medicine and Pharmacy, 300041 Timisoara, Romania
- 3Second Department of Internal Medicine, “Victor Babes” University of Medicine and Pharmacy, 300041 Timisoara, Romania
- 4First Department of Internal Medicine, “Victor Babes” University of Medicine and Pharmacy, 300041 Timisoara, Romania
- 5Multidisciplinary Research Center for Malignant Hematological Diseases (CCMHM), “Victor Babes” University of Medicine and Pharmacy, 300041 Timisoara, Romania
Abstract
Background: Body-composition changes during routine obesity pharmacotherapy require cautious interpretation. Methods: This retrospective observational cohort included 59 adults with paired InBody 770 assessments: 53 receiving tirzepatide and 6 receiving semaglutide. Paired changes and relative device-estimated muscle mass loss were analyzed in all 59; component-share analyses were restricted to the 51 achieving ≥5% weight loss. Analyses used rank-based methods and exploratory robust regression. Results: Recorded treatment duration was a median of 7.0 months, and median observed weight loss was 12.11%. Median fat mass and device-estimated muscle mass losses were 9.9 and 2.3 kg, respectively. Among the 51 participants achieving ≥5% weight loss, median fat, device-estimated muscle, and residual shares were 73.95%, 14.91%, and 10.85%. Each additional five percentage points of weight loss was associated with 2.47 percentage points greater relative device-estimated muscle mass loss (95% CI, 1.89 to 3.05). The corresponding fully adjusted association with muscle share was −0.52 percentage points (95% CI, −1.66 to 0.62); this does not establish stability or equivalence. Final drug-specific dose intensity was not statistically associated with either outcome in the adjusted models. Conclusions: Weight loss observed in this selected, predominantly tirzepatide-treated cohort was mainly accounted for by estimated fat mass reduction. Larger observed weight-loss responses accompanied greater device-estimated muscle mass reductions. Muscle-share estimates were uncertain and model-dependent. The study cannot establish causal medication effects or functional consequences.
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BibTeX
@article{tomescu2026weightloss,
title = {{Weight-Loss Magnitude, Fat Mass, and Device-Estimated Muscle Mass Loss During Obesity Pharmacotherapy}},
author = {Cristina Tomescu and Alin Albai and Vlad Florian Avram and Sandra Timar and Anamaria Cipu and Bogdan Timar},
journal = {Journal of Clinical Medicine},
year = {2026},
month = oct,
doi = {10.3390/jcm15208008},
url = {https://www.mdpi.com/2077-0383/15/20/8008},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Weight-Loss Magnitude, Fat Mass, and Device-Estimated Muscle Mass Loss During Obesity Pharmacotherapy
AU - Cristina Tomescu
AU - Alin Albai
AU - Vlad Florian Avram
AU - Sandra Timar
AU - Anamaria Cipu
AU - Bogdan Timar
PY - 2026
DA - 2026/10/01
JO - Journal of Clinical Medicine
DO - 10.3390/jcm15208008
UR - https://www.mdpi.com/2077-0383/15/20/8008
AB - Background: Body-composition changes during routine obesity pharmacotherapy require cautious interpretation. Methods: This retrospective observational cohort included 59 adults with paired InBody 770 assessments: 53 receiving tirzepatide and 6 receiving semaglutide. Paired changes and relative device-estimated muscle mass loss were analyzed in all 59; component-share analyses were restricted to the 51 achieving ≥5% weight loss. Analyses used rank-based methods and exploratory robust regression. Results: Recorded treatment duration was a median of 7.0 months, and median observed weight loss was 12.11%. Median fat mass and device-estimated muscle mass losses were 9.9 and 2.3 kg, respectively. Among the 51 participants achieving ≥5% weight loss, median fat, device-estimated muscle, and residual shares were 73.95%, 14.91%, and 10.85%. Each additional five percentage points of weight loss was associated with 2.47 percentage points greater relative device-estimated muscle mass loss (95% CI, 1.89 to 3.05). The corresponding fully adjusted association with muscle share was −0.52 percentage points (95% CI, −1.66 to 0.62); this does not establish stability or equivalence. Final drug-specific dose intensity was not statistically associated with either outcome in the adjusted models. Conclusions: Weight loss observed in this selected, predominantly tirzepatide-treated cohort was mainly accounted for by estimated fat mass reduction. Larger observed weight-loss responses accompanied greater device-estimated muscle mass reductions. Muscle-share estimates were uncertain and model-dependent. The study cannot establish causal medication effects or functional consequences.
SN - 2077-0383
ER -