Online Clinical Investigations

Evaluating Muscle Mass by Using Markers of Kidney Function: Development of the Sarcopenia Index

Kashani, Kianoush B. MD^1,2; Frazee, Erin N. PharmD, RPh³; Kukrálová, Lucie MD⁴; Sarvottam, Kumar MD²; Herasevich, Vitaly MD, PhD⁵; Young, Phillip M. MD⁶; Kashyap, Rahul MBBS²; Lieske, John C. MD^1,7

Author Information

¹Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN.

²Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic, Rochester, MN.

³Department of Pharmacy, Mayo Clinic, Rochester, MN.

⁴Charles University in Prague, Faculty of Medicine in Hradec Kralove, Czech Republic, Europe.

⁵Department of Anesthesiology, Mayo Clinic, Rochester, MN.

⁶Department of Radiology, Mayo Clinic, Rochester, MN.

⁷Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.

Dr. Kashani had full access to all of the data in the study and played an essential role in the study design, data collection, and the writing of the article. Drs. Frazee and Lieske provided significant intellectual contributions and participated in the critical review of the article. Drs. Herasevich, Kashyap, and Kukrálová substantially participated in the data collection and some of the analysis. Dr. Sarvottam assisted with preparation of data for the revision and reviewed all CT scans to abstract additional data. All authors read and approved the final article.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website (http://journals.lww.com/ccmjournal).

The institution received research funds from ASTUTE Medical for the original study. Authors retrospectively analyzed data from the funded prospective observational study. The company was neither involved in the design or conduct of the study nor the article construction and content. None of the authors received any direct funds from the above-named company.

Dr. Kashani is the recipient of the Mayo Clinic Department of Medicine Write-up and Publish (WRAP) grant which provided five business days for completion of this article. The remaining authors have disclosed that they do not have any potential conflicts of interest.

For information regarding this article, E-mail: [email protected]

Critical Care Medicine 45(1):p e23-e29, January 2017. | DOI: 10.1097/CCM.0000000000002013

Abstract

Objectives:

Sarcopenia is associated with a poor prognosis in the ICU. The purpose of this study was to describe a simple sarcopenia index using routinely available renal biomarkers and evaluate its association with muscle mass and patient outcomes.

Design:

A retrospective cohort study.

Setting:

A tertiary-care medical center.

Patients:

High-risk adult ICU patients from October 2008 to December 2010.

Interventions:

The gold standard for muscle mass was quantified with the paraspinal muscle surface area at the L4 vertebrae in the subset of individuals with an abdominal CT scan. Using Pearson’s correlation coefficient, serum creatinine-to-serum cystatin C ratio was found to be the best performer in the estimation of muscle mass. The relationship between sarcopenia index and hospital and 90-day mortality, and the length of mechanical ventilation was evaluated.

Measurements and Main Results:

Out of 226 enrolled patients, 123 (54%) were female, and 198 (87%) were white. Median (interquartile range) age, body mass index, and body surface area were 68 (57–77) years, 28 (24–34) kg/m², and 1.9 (1.7–2.2) m², respectively. The mean (± sd) Acute Physiology and Chronic Health Evaluation III was 70 (± 22). ICU, hospital, and 90-day mortality rates were 5%, 12%, and 20%, respectively. The correlation (r) between sarcopenia index and muscle mass was 0.62 and coefficient of determination (r²) was 0.27 (p < 0.0001). After adjustment for Acute Physiology and Chronic Health Evaluation III, body surface area, and age, sarcopenia index was independently predictive of both hospital (p = 0.001) and 90-day mortality (p < 0.0001). Among the 131 patients on mechanical ventilator, the duration of mechanical ventilation was significantly lower on those with higher sarcopenia index (–1 d for each 10 unit of sarcopenia index [95% CI, –1.4 to –0.2; p = 0.006]).

Conclusions:

The sarcopenia index is a fair measure for muscle mass estimation among ICU patients and can modestly predict hospital and 90-day mortality among patients who do not have acute kidney injury at the time of measurement.

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Evaluating Muscle Mass by Using Markers of Kidney Function: Development of the Sarcopenia Index