Sarcopenia, defined as the loss of muscle mass, is a growing public health concern, and is an underrecognized problem in adults with Chronic Kidney Disease (CKD). The clinical diagnosis of sarcopenia can be made via measurement of appendicular lean mass index (ALMi, indexed to height by m2), traditionally obtained through whole-body dual-energy X-ray absorptiometry (DXA) scans, however these are not frequently performed. As a result, large population studies examining the relationship between CKD and sarcopenia are lacking.

Using databases held at the Manitoba Centre for Health Policy, we identified adults who had at least one DXA scan linkable to serum creatinine values within 365 days, between 2007 and 2022. Serum creatinine was used to calculate estimated glomerular filtration rate, and estimated ALMi (eALMi) was calculated through central DXA scans via a previously developed algorithm. We constructed Linear, logistic, and Cox proportional hazards models to examine the relationship between CKD, sarcopenia, and adverse clinical outcomes.

Our CKD cohort contained 24,660 individuals (64.4 ± 12.5 years, 84.4% female), with 3,204 individuals (13.0%) having eALMi indicating sarcopenia. 22,648 individuals (91.8%) had eGFR <= 60, and 2,012 (8.2%) had eGFR < 60. After adjustment for age, sex, estimated central mass index, and comorbid conditions, both sarcopenia and declining eALMi were also associated with adverse clinical outcomes including hospitalization and emergency room visits, home care use, long-term care use, and all-cause mortality. Additionally, the presence of eGFR < 60 was associated with higher odds of sarcopenia (OR: 1.39; 95% CI: 1.16–1.67), and lower eALMi (-0.057; 95% CI: -0.081, -0.034). In individuals with two DXA scans (n=2,985), eGFR < 60 at baseline was associated with a larger decline in eALMi compared to individuals with preserved eGFR (OR: 1.61; 95% CI: 1.05–2.45).

Our results show that CKD is associated with sarcopenia and leads to more rapid declines in appendicular lean mass over time. Furthermore, we demonstrate that eALMi as derived from routine central DXA scanning is associated with long-term downstream adverse clinical outcomes. These findings validate our central DXA based measurement of eALMi and sarcopenia and highlight the importance preservation of muscle mass in individuals with CKD.