Association between serum albumin and mortality in dialysis patients is partly explained by inflammation, and not by malnutrition.

Abstract

OBJECTIVE:

We investigated the effects of inflammatory and nutritional status on the association between serum albumin and mortality in hemodialysis (HD) and peritoneal dialysis (PD) patients.

DESIGN AND PATIENTS:

This was a prospective cohort study of incident dialysis patients starting HD or PD. Inflammation (C-reactive protein >or=5 or >or=10 mg/L), malnutrition (1 to 5 on the 7-point subjective global assessment [SGA]), and low protein intake (normalized protein equivalent of nitrogen appearance [nPNA] <0.99 g/kg/day) were measured at 3 months after the start of dialysis.

SETTING:

The study involved 38 dialysis centers in The Netherlands.

MAIN OUTCOME MEASURE:

We ascertained all-cause mortality during the first 2 years after the start of dialysis.

RESULTS:

In total, 700 patients were included (mean SD age, 59 [+/-15] years; serum albumin, 3.3 (0.7) g/dL; 60% men; 454 starting HD, and 246 starting PD). The 2-year mortality was 21%. In HD patients, the mortality (hazard ratio [HR], with 95% confidence interval [95% CI]) per unit decrease in serum albumin (g/dL) was 1.47 (95% CI, 1.07 to 2.00). Adjustment for SGA did not decrease this risk, whereas adjustment for nPNA decreased the HR to 1.45 (95% CI, 1.06 to 1.97). The mortality risk decreased to 1.30 (95% CI, 0.95 to 1.78) after adjustment for inflammation, and did not further decrease after additional adjustment for SGA and nPNA. Additional adjustments for age, sex, and comorbidity decreased the HR to 1.09 (95% CI, 0.79 to 1.51). In PD patients, the effects of adjustments on the mortality risk of serum albumin (1.38; 95% CI, 0.87 to 2.20) were similar.

CONCLUSION:

In dialysis patients, a 1-g/dL decrease in serum albumin was associated with an increased mortality risk of 47% in HD patients and 38% in PD patients. These mortality risks were in part explained by the inflammatory pathway. The mortality risks associated with serum albumin were not a consequence of malnutrition, as measured with SGA and nPNA. These findings imply that nutritional status cannot be assessed with precision by the measurement of serum albumin in dialysis patients.

• Authors: Renée de Mutsert, Diana C Grootendorst, Fleur Indemans, Elisabeth W Boeschoten, Raymond T Krediet, Friedo W Dekker, Netherlands Cooperative Study on the Adequacy of Dialysis-II Study Group
• Journal: Journal of renal nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation (J Ren Nutr) Vol. 19 Issue 2 Pg. 127-35 (Mar 2009) ISSN: 1532-8503 [Electronic] United States
• PMID: 19218039 (Publication Type: Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers
• Dietary Proteins
• Serum Albumin
• C-Reactive Protein

Topics

• Biomarkers (blood)
• C-Reactive Protein (analysis, metabolism)
• Cause of Death
• Cohort Studies
• Dietary Proteins (administration & dosage)
• Female
• Humans
• Inflammation (blood, etiology, mortality)
• Kidney Failure, Chronic (blood, mortality, therapy)
• Male
• Malnutrition (blood, mortality)
• Middle Aged
• Nutrition Assessment
• Nutritional Status
• Peritoneal Dialysis (mortality)
• Prospective Studies
• Renal Dialysis (mortality)
• Risk Factors
• Serum Albumin (analysis, metabolism)