Foley RN, Parfrey PS, Harnett JD, Kent GM, Murray DC, Barre
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
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).
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
(Stephen Fishbane, M.D., Winthrop University Hospital, Mineola, NY)