Precision of biomarkers to define chronic inflammation in CKD.
OBJECTIVE
Several inflammatory biomarkers have been found to be associated with cardiovascular disease or all-cause mortality in dialysis patients, but their usefulness in clinical practice or as surrogate endpoints is not certain. The purpose of the present study was to determine the intrapatient variation of C-reactive protein, IL-6, fetuin-A and albumin in a population of dialysis patients.


METHODS
Apparently healthy dialysis patients with either a tunneled dialysis catheter or fistula had monthly assessments of these biomarkers for a total of four determinations, and the intraclass correlation coefficients were calculated as measures of intersubject variance.


RESULTS
Our results showed large within-subject variation relative to the total variation in the measurements (31-46%). Having a tunneled catheter as opposed to a fistula was not significantly associated with mean levels, suggesting that chronic subclinical catheter infection does not explain the variation seen in the biomarkers. In contrast, there was a rapid change in these biomarkers with a clinically apparent acute infection.


CONCLUSIONS
These results suggest that these biomarkers have limitations for use as surrogate endpoints in clinical trials due to wide fluctuations, even in apparently clinically healthy individuals.
LaClair
Robert
R
Indiana University School of Medicine, Indianapolis, Indiana, USA.
O'Neal
Kalisha
K
Ofner
Susan
S
Sosa
Marcelo J
MJ
Labarrere
Carlos A
CA
Moe
Sharon M
SM
D015415:Biomarkers / Q000097:blood*; D001798:Blood Proteins / Q000032:analysis; D002097:C-Reactive Protein / Q000032:analysis; D002318:Cardiovascular Diseases / Q000209:etiology; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007206:Individuality; D007249:Inflammation / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000150:complications; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D012709:Serum Albumin / Q000032:analysis; D060749:alpha-2-HS-Glycoprotein
C556354:AHSG protein, human; D015415:Biomarkers; D001798:Blood Proteins; D015850:Interleukin-6; D012709:Serum Albumin; D060749:alpha-2-HS-Glycoprotein; D002097:C-Reactive Protein