A linear relationship between serum high-sensitive C-reactive protein and hemoglobin in hemodialysis patients.
BACKGROUND
Inflammatory process in hemodialysis patients involves hematopoiesis. The aim of the study was to determine the relationship between serum C-reactive protein (CRP) as a marker of inflammation with hemoglobin in patients under hemodialysis.


METHODS
Patients under maintenance hemodialysis for more than 3 months were studied. Serum high-sensitive CRP (hs-CRP) was measured by immunoturbidimetric method and hemoglobin < 11 g/dl was considered as anemia. Iron deficiency anemia was confirmed by percent transferrin saturation < 20 %. Correlation coefficient, linear regression and odds ratio (OR) were used to determine the relationship.


RESULTS
A total of 73 patients aged 50 ± 16.9 years with median hemodialysis duration of 24 (3-280) months entered the study. High serum hs-CRP (> 5 mg/l) was found in 42 (57.5 %) and anemia in 32 (43.8 %) patients. High CRP was significantly associated with anemia OR = 20.8 (95 % CI 5.35-81, p = 0.001). After adjustment for age, dialysis duration, blood indices and serum albumin, the odds of anemia in the high CRP group remained at a significant level of 16.7 (95 % CI 3.7-75, p = 0.001). Hemoglobin levels conversely correlated with serum hs-CRP (r = -0.607, r (2) = 0.36, p = 0.001). In linear regression analysis for each 1 mg/l increase in serum hs-CRP, hemoglobin value increased by 12.4 % (p = 0.002). Serum iron at cutoff level of 54 µg/dl discriminated patients with and without iron deficiency anemia with sensitivity of 93.3 %, specificity of 84 % and accuracy of 90 % (AUC ± SE = 0.901 ± 0.04 (95 % CI, 0.805-0.998, p = 0.001).


CONCLUSIONS
These findings indicate that in hemodialysis patients, the inflammatory process alters hemoglobin level in converse correlation with CRP concentration with a linear relationship pattern. Serum iron <54 µg/dl indicates iron deficiency anemia with high accuracy.
Department of Internal Medicine, Rouhani Hospital, Babol University of Medical Sciences, Babol, Iran, bheidari6@gmail.com.
Behzad
B
Heidari
Muhammad Reza
MR
Fazli
Muhammad Ali Ghazi
MA
Misaeid
Parham
P
Heidari
Niloofar
N
Hakimi
Abbas Ali
AA
Zeraati
D000328:Adult; D000368:Aged; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000150:complications; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D003430:Cross-Sectional Studies; D048909:Diabetes Complications / Q000097:blood / Q000628:therapy; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000150:complications; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000209:etiology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis
D015415:Biomarkers; D006454:Hemoglobins; D002097:C-Reactive Protein