Muscle Wasting in Chronic Kidney Disease: A Collaborative Call to Action

Muscle wasting is a common yet underrecognized complication of chronic kidney disease (CKD). For nephrology providers managing an already complex clinical picture, muscle loss can feel like just one more issue competing for attention. From a renal dietitian’s perspective, however, muscle wasting is not a secondary concern: It is tightly intertwined with morbidity, mortality, quality of life, and health care utilization. Addressing it effectively requires shared understanding, consistent terminology, and a collaborative, interdisciplinary approach.

Defining muscle wasting in CKD

One challenge in understanding muscle wasting in CKD is the inconsistent use of terminology. Several related but distinct conditions are often used interchangeably:

• Sarcopenia refers to a gradual decline in muscle mass and function associated with aging.¹
• Muscle atrophy describes more rapid muscle loss due to acute catabolic stress (such as sepsis or cancer) or undernutrition, often occurring over days to weeks.¹
• Protein energy wasting (PEW) syndrome involves the simultaneous loss of body protein and energy stores, and it is a recognized contributor to muscle wasting in CKD.¹

Distinguishing among these conditions is not academic — it matters clinically. Each has different drivers, timelines, and intervention strategies. Without clarity, it becomes difficult to estimate prevalence, identify causation, or implement targeted prevention and treatment strategies.²

Estimates of muscle-loss prevalence in CKD vary widely, ranging from 4% to 42%, with higher rates observed in dialysis populations (approximately 13.7% to 42%).2 This broad range reflects not only differences in patient populations and disease severity, but also variability in definitions and assessment methods. What is consistent across studies, however, is that muscle wasting becomes more prevalent as kidney disease progresses

Assessing muscle wasting in patients with CKD

The consequences of muscle wasting extend far beyond body composition. Loss of muscle mass and function impairs patients’ ability to perform basic activities of daily living, significantly reducing their quality of life. It is also associated with higher hospitalization rates, increased health care costs, and increased mortality.2,7 From a patient-centered and system-level perspective, muscle preservation is a meaningful and measurable outcome

Historically, muscle wasting in CKD was largely attributed to malnutrition, often inferred from low serum albumin levels.2 Decades of research have since clarified that albumin — particularly when used in isolation — is an unreliable marker of nutritional status and is far more reflective of inflammation and illness severity.3 Reliance on albumin as a nutrition surrogate overlooks the multifactorial drivers of muscle loss in CKD

Muscle wasting can be assessed using a combination of tools. Physical examination — looking for muscle loss in areas such as the temples, clavicles, and shoulders — remains valuable⁸, though it may be challenging in dialysis settings or for patients uncomfortable with touch. Bioimpedance analysis offers a noninvasive way to track body composition changes over time and may be more informative than weight alone. Assessing the issues affecting individual patients can help identify risks for and type of muscle wasting.

Factors contributing to muscle wasting in CKD

CKD itself appears to be an independent contributor to muscle wasting. Multiple overlapping mechanisms are involved, including anemia, metabolic acidosis, insulin resistance, chronic inflammation, and hormonal dysfunction affecting growth hormone, thyroid hormone, testosterone, vitamin D, and insulin signaling.² The hemodialysis process further exacerbates catabolism and protein imbalance, while CKD-associated bone and mineral disorders also play a role in muscle dysfunction and loss.²

Protein metabolism in CKD is frequently dysregulated, with impaired anabolic signaling and increased proteolysis. Even when dietary intake appears adequate, these metabolic disturbances can blunt the muscle’s ability to synthesize and retain protein.²

Emerging evidence highlights the role of gut microbiota imbalance in CKD-related muscle wasting. Dysbiosis contributes to systemic inflammation, insulin resistance, and mitochondrial dysfunction, in part through increased production of uremic toxins.² These toxins can further impair muscle metabolism and function, creating a feedback loop that accelerates muscle loss. This connection reinforces the importance of dietary fiber, gut health, and careful consideration of antibiotic exposure in CKD care.

Reduced physical activity is common in CKD and is often driven by fatigue, depression, cardiovascular disease, and other comorbidities. Inactivity itself is a well-established risk factor for muscle wasting. Importantly, studies demonstrate that in elderly patients with CKD, the combination of adequate protein intake and increased physical activity is more effective at improving muscle mass than increased protein intake alone.⁴

That said, increasing physical activity is not feasible for all patients. In these cases, alternatives such as physical therapy and neuromuscular electrical stimulation have shown benefit and should be considered.⁵

Low vitamin D levels are common in CKD and are associated with reduced muscle strength and increased fall risk.2 Vitamin D also plays a role in insulin secretion and protein synthesis, both of which are relevant to muscle maintenance.6 Routine monitoring and appropriate supplementation represent a relatively simple intervention with potential downstream benefits for muscle function

The evolving renal diet paradigm — emphasizing cardiovascular health and individualized nutrient restriction — aligns well with muscle preservation. Diets that reduce inflammation, support gut microbiota balance, and lower dietary acid load may indirectly reduce muscle wasting risk.2 This approach also makes dietary adherence more realistic and sustainable for patients

Practical muscle-preserving strategies in CKD

• Regularly monitor vitamin D levels and supplement as indicated
• Encourage aerobic and resistance exercise when feasible, with referrals to physical therapy as needed
• Consider neuromuscular electrical stimulation for patients with limited mobility
• Refer patients early to a renal dietitian for individualized nutrition support
• Consider probiotics and prebiotics, particularly following antibiotic use
• Use bioimpedance or other body composition tools when available

How dietitians can support nephrologists and patients:

• Provide guidance on protein intake or ketoanalogue use for patients with poor appetite, conservative CKD management, or short-term increased protein needs (eg, surgery)
• Reduce dietary acid load, support gut microbiota, and increase fiber through greater fruit, vegetable, and whole grain intake
• Promote adequate protein-sparing calorie intake (30–35 kcal/kg)
• Assess gut health and provide targeted dietary strategies
• Perform nutrition-focused physical exams to identify early muscle wasting

Conclusion

Muscle wasting in CKD is common, complex, and clinically significant — but it is not inevitable. By recognizing CKD as an active driver of muscle loss and addressing contributing factors through coordinated medical, nutritional, and functional interventions, nephrology teams can meaningfully improve patient outcomes. Dietitians stand ready to partner in this work, helping nephrologists support not only kidney health, but strength, function, and quality of life for patients living with CKD

1. .Dardevet D, Savary-Auzeloux I, Remond D, Mosoni L. Commentaries on Viewpoint: Muscle atrophy is not always sarcopenia. J Appl Physiol. 2012;113(4):680-684. doi:10.1152/japplphysiol.00667.2012
2. .Cheng TC, Huang SH, Kao CL, et al. Muscle wasting in chronic kidney disease: mechanism and clinical implications — a narrative review. Int J Mol Sci. 2022;23(11). doi:10.3390/ijms23116047
3. Ikizler TA, Burrowes JD, Byham-Gray LD, et al. KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update. Am J Kidney Dis. 2020;76(3):S1-S107. doi:10.1053/j.ajkd.2020.05.006
4. Isaka Y. Optimal protein intake in pre-dialysis chronic kidney disease patients with sarcopenia: an overview. Nutrients. 2021;13(4):1205. doi:10.3390/nu13041205
5. Wang K, Liu Q, Tang M, et al. Chronic kidney disease-induced muscle atrophy: molecular mechanisms and promising therapies. Biochem Pharmacol. 2023;208:115407. doi:10.1016/j.bcp.2022.115407
6. Massini G, Caldiroli L, Molinari P, Carminati FMI, Castellano G, Vettoretti S. Nutritional strategies to prevent muscle loss and sarcopenia in chronic kidney disease: What do we currently know? Nutrients. 2023;15(14):3107. doi:10.3390/nu15143107
7. Yi SHJ& HS. Clinical features and molecular mechanism of muscle wasting in end-stage renal disease. BMB Rep. 2023;56(8):426-438. doi:10.5483/BMBRep.2023-0097
8. McCann L. Pocket Guide to Nutrition Assessment of the Patient with Kidney Disease. 6th ed. National Kidney Foundation; 2021.