Creatinine Muscle Index: Predicting Deadly Kidney Disease Complication

February 12, 2026 Dr. Michael Lee – Health Editor Health

A new index utilizing creatinine levels can identify a potentially fatal complication of chronic kidney disease (CKD) – sarcopenia – according to research published this week. The Creatinine Muscle Index (CMI) offers a way to assess muscle health in CKD patients, a population particularly vulnerable to muscle wasting and its associated health risks.

Sarcopenia, characterized by loss of muscle mass and function, is linked to increased mortality, diminished quality of life, and reduced physical capabilities in individuals with CKD, researchers have found. The CMI, which reflects creatinine generation and excretion, is independently associated with appendicular muscle mass (ACM) and muscle function, even in those not yet undergoing dialysis.

Thomas McDonnell, lead author of one study examining the CMI, explained that the index provides a valuable tool for identifying patients at risk. His team’s research, conducted with colleagues at the Donal O’Donoghue Renal Research Centre and the University of Manchester, focused on a non-dialysis CKD population. The study, published in PLOS Medicine, details the associations between CMI and markers of sarcopenia.

Researchers at Hangzhou TCM Hospital in China have likewise investigated a modified creatinine index, finding a correlation between it and both muscle strength and mortality rates in patients receiving hemodialysis. Their work, published in Renal Failure in October 2022, highlights the broader implications of creatinine-based assessments for CKD patients.

The CMI is calculated using estimations of glomerular filtration rate, cystatin C, and serum creatinine. This composite measure provides a more comprehensive evaluation of muscle health than traditional methods, according to the research. The findings suggest that monitoring CMI could help clinicians proactively manage sarcopenia and improve outcomes for individuals with CKD.

The research indicates that patients with CKD experience decreased muscle protein synthesis and increased protein breakdown, leading to muscle wasting and functional decline. Identifying these patients early is crucial, as sarcopenia significantly impacts overall health and survival rates.