Anemia: Fast Facts (Peer reviewed publications)
Study examines prognostic value of hemoglobin levels in the critically ill
A prospective observational cohort study was conducted in critically ill patients with acute renal failure requiring dialysis in order to assess the prognostic value of hemoglobin levels. A total of 206 consecutive patients from 2 adult medical intensive care units were studied and 63% of the patient cohort were anemic at baseline (anemia was defined as hemoglobin below 9 g/dL).
The prognostic value of the hemoglobin level was measured by evaluating the survival rate of the patients. Multivariable analysis identified the following 3 factors which were independently associated with 28-day death: 1) SOFA score (sepsis-related organ failure assessment) score, which quantitatively describes the degree of organ dysfunction; 2) hemoglobin <9 g/dL (adjusted odds ratio 2.4, 95% confidence interval 1.1-5.2); and 3) age. Overall, the 28-day mortality was 48%. The researchers concluded, "initial hemoglobin levels may be helpful in identifying patients with acute renal failure requiring dialysis at high risk of death."
NAAC experts believe this is an interesting study, however the low initial hemoglobin level makes interpretation difficult. We do not know if the anemia is merely a marker for higher risk patients or whether treatment of anemia might improve outcomes. Clearly, severe anemia of this magnitude is a poor prognostic indicator, but of greater clinical relevance is the prognostic value of more moderate degrees of anemia.
For additional information on this research, please reference the source article:
du Cheyron D, Parienti JJ, Fekih-Hassen M, Daubin C, Charbonneau P. Impact of anemia on outcome in critically ill patients with severe acute renal failure. Intensive Care Med. 2005 Oct 5; [Epub ahead of print]
Retrospective study determines physicians adhere to NKF-K/DOQI guidelines
A retrospective study evaluated 160,028 patients from 2 databases (31,267 from the Fresenius Medical Care-North America database; 128,761 Medicare patients). The purpose of the study was to evaluate prescribing patterns of epoetin alfa for achieving target hemoglobin levels recommended by the National Kidney Foundation - Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) in patients with end-stage renal disease on hemodialysis. This endpoint was measured by analyzing monthly hemoglobin levels and epoetin alfa dosing. A longitudinal appraisal of the Fresenius data set revealed 98.8% of patients had persistent hemoglobin levels >12.0 g/dL with epoetin alfa dosing adjusted to maintain this range. Analysis of the Medicare data set showed epoetin alfa dosing was appropriately titrated in patients with a 3-month average hemoglobin level <11.0 g/dL in order to bring hemoglobin values to NKF-K/DOQI recommended levels.
Overall, less than 0.4% of patients who received epoetin alfa experienced anemia that would not resolve or respond to medication dosing titration. The researchers concluded, "In these analyses, few hemodialysis patients experienced persistent anemia while being administered high epoetin alfa doses…and… physicians appeared to appropriately adjust [epoetin alfa] doses to achieve hemoglobin levels recommended by the NKF-K/DOQI guidelines."
For additional information on this research, please reference the source article:
Collins AJ, Brenner RM, Ofman JJ, et al. Epoetin alfa use in patients with ESRD: an analysis of recent US prescribing patterns and hemoglobin outcomes. Am J Kidney Dis. 2005;46:481-8
NAAC Experts believe this is an important study as the Centers for Medicare & Medicaid Services is preparing to modify erythropoietin payment policy for dialysis patients. This study shows that the concern of CMS, that nephrologists do not adequately monitor anemia in this patients or adjust erythropoietin doses appropriate, is not correct.
Reviewing the role of anemia in heart failure
In an article written by Vasu et al., the role of anemia in heart failure is reviewed. The authors identify anemia as a significant risk factor which is often prognostic of morbidity and mortality. Various etiologies of anemia in heart failure are reviewed, including inhibition of erythropoiesis due to multiple factors, with specific references to the affects of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, and a call for continued investigation into the important relationship between anemia and congestive heart failure.
For additional information on this research, please reference the source article:
Vasu S, Kelly P, Lawson WE. Anemia in heart failure - A concise review. Clinical Cardiology. 2005;28:454-458
Anemia may predict risk of ischemic complications in patients with giant cell arteritis
The Mayo Clinic defines giant cell arteritis (GCA) as "Inflammation of arteries, most frequently occurring in the arteries of the head" (also known as cranial arteritis, temporal arteritis, or Horton's disease). An article authored by Gonzalez-Gay et al. reports on the outcomes of patients with GCA and the extent to which ischemic manifestations play a role in clinical outcomes. Their study looked at 240 consecutive patients with GCA previously proven by biopsy in a single institution. The study reviewed laboratory markers of inflammation and their value as prognostic factors of severe ischemic manifestations, such as cerebrovascular accidents, ophthalmic complications, claudication, and stenosis. Anemia was defined as a hemoglobin value <12 g/dL, and 131 patients (54.6%) were determined to be anemic, while 117 (48.8%) had thrombocytosis and 68 (28.3%) had leukocytosis. The researchers stated, "Anemia was more commonly observed in patients without severe ischemic manifestations (61.5% versus 48.9% in those with severe ischemic manifestation; p = 0.05) and in patients with constitutional syndrome or fever (p < 0.001)." However, a multivariate logistic regression analysis found anemia to be a negative predictor for the development of severe ischemic manifestations of GCA. The authors concluded, "The presence of anemia may negatively predict the risk of severe ischemic complications in GCA patients."
For additional information on this research, please reference the source article:
Gonzalez-Gay MA, Lopez-Diaz MJ, Barros S, et al.Giant cell arteritis: laboratory tests at the time of diagnosis in a series of 240 patients. Medicine (Baltimore). 2005;84:277-90
Research reveals certain hematologic differences between African-Americans and whites
A study evaluated the blood of 1491 African-American patients and 31 005 white patients, with approximately equal division between men and women in each group. In this report, the authors have gathered a large amount of hematology screening information from patients of African-American or white origin. The authors found that there were significant differences in the hemoglobin concentration, MCV, transferrin saturation, ferritin and white blood cell counts between the groups that could not be accounted for even after patients with iron deficiency or alpha thalassemia trait were removed from the comparison. African-Americans had lower hemoglobin concentrations, lower MCVs, lower percent transferrin saturation, lower white cell counts (that could be accounted for by lower granulocyte counts) and higher serum ferritins. Using standard reference cut-offs, 16.2% of non-iron deficient African-American women would have a hemoglobin <12.0 gm/dL compared to 3.9% of white women. Only part of this difference could be accounted for by the presence of alpha thalassemia trait, and the authors state that this is not of practical consequence since means for routine clinical diagnosis of alpha thalassemia trait are not available. Thus, it is important to recognize that these differences exist and to include this information when making decisions about working up anemia in patients from different ethnic backgrounds. The authors conclude that creating reference laboratory ranges for different ethnic groups is not feasible and, consequently, this is "information that the physician must possess that becomes one of the many factors that (is designated) as clinical judgment."
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