Total Convection Affects Serum β2 Microglobulin and C-Reactive Protein but Not Erythropoietin Requirement following Post-Dilutional Hemodiafiltration.
BACKGROUND
Inflammation and increased erythropoiesis stimulating agents (ESA) requirement are frequently associated in patients on dialysis. On-line hemodiafiltration (ol-HDF), putting together high levels of diffusion, and convection could improve both conditions. However, it is still not known which depurative component plays a major role in determining this result. The aim of the study was to evaluate the role of convection and diffusion on long-term variations of serum β2 microglobulin (Δβ2M), high-sensitive C-reactive protein (ΔhsCRP) concentrations, and ESA requirement (ΔESA) in ol-HDF.


METHODS
Seventy-three patients prevalent on high flux HD (hfHD) were studied. Thirty-eight patients were switched from hfHD to post-dilutional ol-HDF (Study group); the other 35 patients were considered the Control group. At 6 and 12 months, the effects of ol-HDF and hfHD on ΔhsCRP, ΔB2M, and ΔESA (U/kg/week) were evaluated. Other variables considered were body weight (BW), serum albumin (sAlb), hemoglobin (Hb), and equilibrated Kt/V (eKt/V). Iron therapy and ESA were administered intravenously according to the K/DOQI guidelines in order to maintain transferrin saturation between 20 and 40%, serum ferritin between 150 and 500 ng/ml and Hb between 11 and 12 g/dl. Qb, treatment time and Qd remained constant. Ol-HDF and hfHD were performed using membranes of size 1.9-2.1 sqm. Ultrapure dialysate and substitution fluid were employed in both HDF and HD treatments. Data are expressed as mean ± SD. Paired t test, Mann-Whitney U test, and simple and multiple regression analyses were employed for statistical evaluation.


RESULTS



METHODS
total convective volume (TCV) was 22.1 ± 1.9 l/session. A significant reduction of hsCRP: from 6.8 ± 7.1 to 2.3 ± 2.4 mg/dl (p < 0.001), β2M: from 36.5 ± 14.4 to 24.7 ± 8.6 mg/dl (p < 0.0001) and ESAdose: from 107 ± 67 to 65 ± 44 U/kg/week (p < 0.005) was observed. No significant variations of Hb, BW and sAlb were seen. A significant inverse correlation was found between TCV and Δβ2M (r = -0.627; p < 0.0001), and TCV and ΔhsCRP (r = -0.514; p < 0.0001); no correlation between TCV and ΔESAdose was observed. No correlation was found between eKt/V and Δβ2M, ΔhsCRP, and ΔESAdose. Multiple regression analysis with ΔESAdose as dependent variable showed ΔhsCRP as the only significantly associated independent factor (p < 0.01).


METHODS
no significant variations of hsCRP, β2M, and ESAdose were observed over time.


CONCLUSIONS
Ol-HDF induces a long-term significant reduction in pre-dialysis β2M and hsCRP concentrations. The magnitude of reduction is directly correlated to the amount of TCV achieved but not on eKt/V. The observed reduction in ESAdose requirement is independent either on convection or diffusion, but is directly associated to the concomitant reduction of inflammation.
U.O. Nephrology, Spedali Civili and University of Brescia, Brescia, Italy.
Ezio
E
Movilli
Corrado
C
Camerini
Paola
P
Gaggia
Roberto
R
Zubani
Paolo
P
Feller
Chiara
C
Salviani
Annalisa
A
Facchini
Giovanni
G
Cancarini
D000368:Aged; D001835:Body Weight; D002097:C-Reactive Protein / Q000378:metabolism*; D018481:Convection; D004058:Diffusion; D004921:Erythropoietin / Q000008:administration & dosage*; D005260:Female; D005293:Ferritins / Q000097:blood; D006397:Hematinics / Q000008:administration & dosage*; D017583:Hemodiafiltration / Q000379:methods*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000628:therapy*; D012709:Serum Albumin / Q000378:metabolism; D013997:Time Factors; D014168:Transferrin / Q000378:metabolism; D001613:beta 2-Microglobulin / Q000097:blood*
D006397:Hematinics; D006454:Hemoglobins; D012709:Serum Albumin; D014168:Transferrin; D001613:beta 2-Microglobulin; D004921:Erythropoietin; D002097:C-Reactive Protein; D005293:Ferritins; D007501:Iron