Currently there is no standard way to detect age-related skeletal muscle loss in patients with chronic kidney disease. Investigators are working on finding rapid and inexpensive ways to measure muscle size and fat within the muscle.

The accelerated muscle wasting associated with chronic kidney disease (CKD) is a source of morbidity and an increased incidence of bone fracture secondary to falls. However, sarcopenia secondary to CKD is not routinely screened or assessed in this patient population. This protocol, "Quantitative Ultrasound Assessment of Lean and Intramuscular Adipose Tissue in Veterans Project" (i.e., QUALITY VETS) is a VA Center for Innovation (VACI) funded pilot study with the purpose of using a clinically viable sarcopenia screening approach for Veterans with CKD who are currently receiving care at the Renal Service.

The investigative team will screen and assess diminished muscle mass, quality, and performance in Veterans with CKD (Stage 3 and 4), and also examine the relationship between the muscle characteristics and estimated fall risk within the sample. Key outcome measures will be obtained within the domains of muscle performance (peak grip strength), functional status (Short Physical Performance Battery), estimates of tissue/body composition (diagnostic ultrasound and DXA), and fall risk (Timed Up-and-Go test). Secondary measures will include questionnaires regarding of fall avoidance, physical activity, depression, and quality of life (QoL).

The general analysis approach will be to characterize the proportion of participants with: sarcopenia based on the European Working Group on Sarcopenia in Older People (EWGSOP) algorithm, low muscle quality based on preliminary echogenicity cut off values and criterion strength values, and an elevated risk of falling based on the Timed Up-and-Go age-dependent cut off values. Investigators will determine the magnitude of association between the skeletal muscle outcomes and fall risk within the participant sample. Hazard ratios will be used to estimate the impact of the sarcopenia classification and echogenicity values on the positive classification of fall risk.

The optimal treatment of Veterans with CKD who have an elevated risk of falls may be enhanced by the timely identification of accelerated muscle changes. The QUALITY-VETS Project will help to determine appropriate screening and assessment strategies that could be implemented in subsequent longitudinal studies involving exercise interventions and fall prevention training.

Inclusion Criteria:

• Ambulatory patients (with or without a gait aid)
• 18-84.9 years of age with CKD stage 3 or 4
• Receiving care at the DC or SF VA Medical Center Renal Service
• Able to speak and read English
• Orientation to person, place, and time

Exclusion Criteria:

• Acute renal failure
• Pregnancy
• Any uncontrolled cardiovascular or musculoskeletal disease that, in the opinion of the principal investigator, could make participation unsafe
• Body size exceeds the dimensional limits of the DXA scanner

Participating Veterans in this study will undergo their standard examination by the DC or SF VA Medical Center Renal Service staff physicians and will be formally staged for CKD. Fifty adult patients with Stage 3 or 4 CKD (i.e., a definitive CKD diagnosis, but prior to the need for dialysis) will be enrolled following consent and then scheduled for the study assessments at their local study center.

Data will be shared between the two study sites: the Washington DC and San Francisco VA Medical Centers