Declining Serum Albumin With Stable Body Mass Index: A Mortality Indicator in Predialysis Chronic Kidney Disease

This study aimed to investigate changes in nutritional markers in patients with predialysis chronic kidney disease (CKD) and stable body mass index (BMI).

We analyzed data from a nationwide cohort of US Veterans with advanced CKD who transitioned to kidney replacement therapy from October 1, 2007, through March 31, 2015. We identified 20,164 U.S. veterans with stable BMI and multiple serum albumin measurements. We calculated intraindividual slopes of serum albumin using mixed effects models for 3 years preceding dialysis. We examined the association of serum albumin slope with mortality after dialysis initiation using Cox proportional hazards models adjusted for demographic characteristics, comorbidities, and baseline estimated glomerular filtration rate and serum albumin.

The cohort had a mean age of 64 years, with 98.3% male and 30% African American participants. Despite maintaining stable BMI, 81% of patients displayed a decline in serum albumin levels in the predialysis period (median slope: -0.09 g/dL/year, 25th and 75th percentile: -0.17, -0.02). A steeper decline in serum albumin over time was associated with significantly higher postdialysis mortality (multivariable-adjusted hazard ratio associated with -1 g/dL/year decline in serum albumin: 1.86, 95% confidence interval: 1.65-2.10, P < .001).

A large proportion of patients with advanced CKD display a clinically relevant decline in serum albumin despite maintaining a stable BMI. Our study highlights the limitations of stable BMI as a marker of nutritional adequacy in advanced CKD, emphasizing the need for more comprehensive nutritional assessments in CKD management.