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

J Ren Nutr. 2025 Sep;35(5):598-606. doi: 10.1053/j.jrn.2025.04.005. Epub 2025 May 6.

Abstract

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

Methods: 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.

Results: 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).

Conclusion: 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.

Keywords: Chronic Kidney Disease [CKD]; Nutritional Assessment; Post Dialysis Mortality; Protein-Energy Wasting [PEW]; Serum Albumin.

MeSH terms

  • Aged
  • Biomarkers / blood
  • Body Mass Index*
  • Cohort Studies
  • Female
  • Glomerular Filtration Rate
  • Humans
  • Male
  • Middle Aged
  • Nutritional Status
  • Proportional Hazards Models
  • Renal Dialysis
  • Renal Insufficiency, Chronic* / blood
  • Renal Insufficiency, Chronic* / mortality
  • Renal Insufficiency, Chronic* / therapy
  • Serum Albumin* / analysis
  • Serum Albumin* / metabolism
  • United States / epidemiology
  • Veterans

Substances

  • Serum Albumin
  • Biomarkers