Clinical Nutrition Open Science · Published 2026-04-17 · DOI 10.1016/j.nutos.2026.100663
Background & Aims: Acute muscle wasting and muscle atrophy are common in hospitalized patients and are associated with increased risk of morbidity and mortality, thus monitoring of muscle mass is crucial for informing early clinical interventions. Creatinine and cystatin C have emerged as promising biomarkers for muscle mass estimation, but less research has investigated the relationship between these measures and provider-assessed muscle loss. The purpose of this study is to examine the association between serum biomarkers and provider-assessed muscle loss in hospitalized patients. Methods: The data in this retrospective cross-sectional study was obtained through patient records of one large tertiary academic medical center from February 2020 to December 2024, including adults with serum creatinine and cystatin C measured at the same time. The primary outcome measure was muscle loss (no loss, mild, moderate, severe) obtained from Nutrition-Focused Physical Exam (NFPE) notes by registered dietitians. Provider notes from visits within 7 days of specimen collection were used. Manual chart review was performed to rule out those with unstable creatinine, end-stage renal disease, and dialysis. Secondary data included age, sex, and body mass index (BMI). The independent variables analyzed were sarcopenia index (creatinine/cystatin C ∗ 100) and estimated body muscle mass using a novel equation developed by Kim et al. (2016). Univariable and multivariable logistic regression analyses, including receiver operating characteristic (ROC) curves, were used to evaluate the association between creatinine and cystatin C-derived indices and any muscle loss. Results: We identified 68 patients for muscle loss analysis, of which 13 were excluded after chart review. The median age of the remaining 55 patients was 32. There were no significant differences in sarcopenia index or estimated body muscle mass between muscle loss groups. When factoring in age, sex, and BMI, sarcopenia index was observed to be significantly associated with muscle loss at any severity (p = 0.024; 95% confidence interval [CI]: 0.92–0.99). Estimated body muscle mass was not found to be significantly associated with muscle loss in any regression models. In general, multivariable binary logistic regression models including sarcopenia index and estimated body muscle mass performed better than those without. Conclusion: Our findings suggest that use of creatinine and cystatin C is a promising direction of research for evaluating muscle loss in hospitalized patients, providing more information than age, sex, and BMI alone. We have laid exploratory, hypothesis-generating groundwork for future study assessing muscle wasting prevalent in critically ill or hospitalized patients. Substantially larger sample sizes to increase predictive power and objective measures of muscle mass such as CT are necessary to translate findings into meaningful clinical interventions. These further studies would support the use of serum biomarkers in routine clinical settings to monitor patient muscle status, contributing towards the development of a reliable and accessible method of muscle mass measurement to improve monitoring and care for critically ill or hospitalized patients.
Abstract from DOAJ. Public domain (CC0 1.0).
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