HDCN Article Review/Hyperlink

Foley RN, Parfrey PS, Harnett JD, Kent GM, Murray DC, Barre PE

The impact of anemia on cardiomyopathy, morbidity, and mortality in ESRD

Am J Kidney Dis (Jul) 28:53-61 1996

The increased death rate of dialysis patients compared to age-matched nonuremics can be explained by several well known factors. The attributable risk due to anemia is unknown, the purpose of this analysis was to specifically address this issue.

A cohort of 432 patients (hemodialysis-261 and peritoneal dialysis-171) was enrolled between 1982 and 1991 at 3 centers in Canada. Patients were followed for a mean of 41 months, and hemoglobin levels were reported as the mean of monthly values during followup. The patient population was unusual in that almost all patients were Caucasian, the leading cause of renal failure was glomerulonephritis, and because most patients were enrolled prior to routine use of recombinant erythropoietin. The primary outcome measures were mortality, and measures of cardiac function and clinical cardiac disease.

One third of patients had a mean hemoglobin of <8.0 g/dl, one-third between 8.0 and 9.5 g/dl, and one-third greater than 9.5 g/dl. After adjusting for relevant covariates, each 1 g/dl decrease in mean hemoglobin was associated with an increased risk of death (odds ratio 1.14, p=0.024), left ventricular dilatation (odds ratio 1.46, p=0.018), and de novo congestive heart failure (odds ratio 1.20, p=0.046).

Comment: This is a well designed and executed study, and provides the best evidence to date of an association between anemia, mortality and cardiac disease. The authors hypothesize that anemia leads to left ventricular dilatation, with secondary hypertrophy, and then to cardiac failure with a resulting increased risk of death.

Since most patients enrolled were not treated with erythropoietin, the mean hemoglobin was lower then current targets used for patients on dialysis. Because of this fact, it is impossible to use information derived from this study to answer a critical clinical question - What is the optimal target hemoglobin/hematocrit concentration during erythropoietin therapy? It would be incorrect to conclude from this article that current targets should be increased. The results of ongoing interventional studies should help answer this question. (Stephen Fishbane, M.D., Winthrop University Hospital, Mineola, NY)