TOPLINE:

Among patients with chronic kidney disease (CKD), adverse muscle composition, characterised by low muscle volume and high muscle fat infiltration, was independently associated with a more than fourfold increased risk for all-cause mortality.

METHODOLOGY:

• Researchers conducted a prospective observational study to evaluate the association between MRI‑defined adverse muscle composition and all-cause mortality in patients with CKD and to compare this association with sarcopenia.
• They analysed data of 894 patients (mean age, 72.2 years; 47.5% women) with CKD (defined as the estimated glomerular filtration rate < 60 mL/min/1.73 m²) from the UK Biobank imaging cohort and 3576 matched control individuals.
• Participants underwent rapid whole-body fat- and water-separated MRI scans; images were analysed to assess thigh muscle volume and muscle fat infiltration.
• Adverse muscle composition was defined as the coexistence of low thigh muscle volume (z score < 25th percentile; < -0.68 SD) and high muscle fat infiltration (> 75th percentile; > 7.7% for men and > 8.82% for women).
• All-cause mortality data were obtained through linkage to national death registries.

TAKEAWAY:

• During a mean follow-up of 3.6 years, 50 patients with CKD died. The risk for all-cause mortality was 2.41-fold higher in patients with CKD vs control individuals (hazard ratio [HR], 2.41; P < .001). The leading causes of death among patients with CKD were diseases of the circulatory system, particularly ischaemic heart disease.
• Adverse muscle composition was independently associated with a more than fourfold increased risk for all-cause mortality (HR, 4.21; P = .007).
• MRI-assessed muscle composition identified a larger proportion of participants with CKD at risk and showed a stronger association with mortality than sarcopenia as defined by the European Working Group on Sarcopenia in Older People 2 and Foundation for the National Institutes of Health criteria.

IN PRACTICE:

"Our findings indicate that CKD patients with AMC [adverse muscle composition], characterized by low muscle volume and high MFI [muscle fat infiltration], are at a greater risk of mortality, and that AMC is independently associated with all-cause mortality in CKD," the authors wrote.

SOURCE:

This study was led by Ainhoa Indurain, MD, Linköping University, Linköping, Sweden. It was published online on April 14, 2026, in the Clinical Journal of the American Society of Nephrology.

LIMITATIONS:

CKD was defined using blood samples collected 7-9 years prior to MRI. The study population consisted mainly of White individuals with early-stage CKD, which may have limited the generalisability of the findings to other ethnic groups or those with advanced CKD. In addition, the relatively small number of mortality events led to wide CIs and some uncertainty regarding the estimated effects.

DISCLOSURES:

This work was supported by the Swedish Research Council, the Swedish Kidney Foundation, and the Swedish Society of Nephrology. Additional support was provided by AstraZeneca and Pfizer, Inc.Some authors reported receiving honoraria; serving in advisory or leadership roles; working as consultants or employees; or holding ownership interests, patents, or royalties with various pharmaceutical companies or organisations.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.