The importance of iron in long-term survival of maintenance hemodialysis patients treated with epoetin-alfa and intravenous iron: analysis of 9.5 years of prospectively collected data.
BACKGROUND
In patients treated by maintenance hemodialysis the relationship to survival of hemoglobin level and administered epoetin-alfa and intravenous iron is controversial. The study aim was to determine effects on patient survival of administered epoetin-alfa and intravenous iron, and of hemoglobin and variables related to iron status.


METHODS
The patients were 1774 treated by maintenance hemodialysis in 3 dialysis units in New York, NY from January 1998 to June, 2007. A patient-centered, coded, electronic patient record used in patient care enabled retrospective analysis of data collected prospectively. For survival analysis, patients were censored when transplanted, transferred to hemodialysis at home or elsewhere, peritoneal dialysis. Univariate Kaplan-Meier analysis was followed by multivariate analysis with Cox's regression, using as variables age, race, gender, major co-morbid conditions, epoetin-alfa and intravenous iron administered, and 15 laboratory tests.


RESULTS
Median age was 59 years, epoetin-alfa (interquartile range) 18,162 (12,099, 27,741) units/week, intravenous iron 301 (202, 455) mg/month, survival 789 (354, 1489) days. Median hemoglobin was 116 (110, 120)g/L, transferrin saturation 29.7 (24.9, 35.1)%, serum ferritin 526 (247, 833) microg/L, serum albumin 39.0 (36.3, 41.5) g/L. Survival was better the higher the hemoglobin, best with > 120 g/L. Epoetin-alfa effect on survival was weak but had statistically significant interaction with intravenous iron. For intravenous iron, survival was best with 1-202 mg/month, slightly worse with 202-455 mg/month; it was worst with no intravenous iron, only slightly better with > 455 mg/month. Survival was worst with transferrin saturation < or = 16%, serum ferritin < or = 100 microg/L, best with transferrin saturation > 25%, serum ferritin > 600 microg/L The effects of each of hemoglobin, intravenous iron, transferrin saturation, and serum ferritin on survival were independently significant and not mediated by other predictors in the model.


CONCLUSIONS
Long term survival of maintenance hemodialysis patients was favorably affected by a relatively high hemoglobin level, by moderate intravenous iron administration, and by indicators of iron sufficiency. It was unfavorably influenced by a low hemoglobin level, and by indicators of iron deficiency.
Pollak
Victor E
VE
MIQS Inc., 2100 Central Avenue, Suite 201, Boulder, Colorado 80301, USA. vpollak@miqs.com
Lorch
Jonathan A
JA
Shukla
Rakesh
R
Satwah
Supriya
S
D000328:Adult; D000368:Aged; D000740:Anemia / Q000188:drug therapy* / Q000209:etiology; D015897:Comorbidity; D004359:Drug Therapy, Combination; D000068817:Epoetin Alfa; D004921:Erythropoietin / Q000627:therapeutic use*; D005260:Female; D005290:Ferric Compounds / Q000008:administration & dosage / Q000627:therapeutic use*; D000077605:Ferric Oxide, Saccharated; D005293:Ferritins / Q000097:blood; D005937:Glucaric Acid; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007262:Infusions, Intravenous; D007505:Iron-Dextran Complex / Q000008:administration & dosage / Q000627:therapeutic use*; D053208:Kaplan-Meier Estimate; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000628:therapy; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011994:Recombinant Proteins; D006435:Renal Dialysis; D012189:Retrospective Studies; D016019:Survival Analysis; D014168:Transferrin / Q000032:analysis
D005290:Ferric Compounds; D006454:Hemoglobins; D011994:Recombinant Proteins; D014168:Transferrin; D004921:Erythropoietin; D000068817:Epoetin Alfa; D007505:Iron-Dextran Complex; D005293:Ferritins; D000077605:Ferric Oxide, Saccharated; D005937:Glucaric Acid; C035552:ferric gluconate