Elevated C-reactive protein (CRP) levels, a marker of inflammation, predict greater requirements of erythropoiesis-stimulating agents (ESAs).
In a study of 1,754 hemodialysis patients, researchers evaluated the association between CRP levels and average hemoglobin levels and per-administration dose of epoetin alfa (EPO) over the three months following the CRP measurement.
The investigators, led by Brian D. Bradbury, DSc, in the Department of Biostatistics and Epidemiology at Amgen, Inc., which makes EPO, identified patients who had at least one CRP measurement and three months of recorded clinical information prior to the index month of CRP measurement (study entry). Subjects had a mean age of 62.6 years and a mean CRP value of 2.89 mg/dL. The study population was 51.5% male and 56.2% white.
Of the 1,754 patients, 502 did not have an EPO dose or hemoglobin data available in all three months following the index CRP. Another 26 did not have complete covariate information, leaving 1,226 patients (70%) for inclusion in multiple variable analyses. Mean hemoglobin levels over the three month follow-up period did not differ according to CRP level.
After adjusting for severity of illness and other potential confounders, patients in the highest CRP quartile (greater than 3.21 mg/dL) were more likely to require significantly higher EPO doses to achieve comparable hemoglobin levels compared with patients who had lower CRP levels, the authors reported in Nephrology Dialysis Transplantation (2008; published online ahead of print). In the third month, the mean per-administration EPO dose was 9340 units for patients in the highest quartile compared with 7,711, 8,391, and 7,821 units for patients in the first, second, and third quartiles.
“These data suggest that monitoring of CRP levels may guide physicians in their diagnosis and treatment of patients with impaired response to ESAs,” the authors wrote.