Anemia status, hemoglobin concentration and outcome after acute stroke: a cohort study.
BACKGROUND
In the setting of an acute stroke, anemia has the potential to worsen brain ischemia, however, the relationship between the entire range of hemoglobin to long-term outcome is not well understood.


METHODS
We examined the association between World Health Organization-defined admission anemia status (hemoglobin<13 in males, <12 g/dl in women) and hemoglobin concentration and 1-year outcome among 859 consecutive patients with acute stroke (ischemic or intracerebral hemorrhage).


RESULTS
The mean baseline hemoglobin concentration was 13.8 +/- 1.7 g/dl (range 8.1 - 18.7). WHO-defined anemia was present in 19% of patients among both women and men. After adjustment for differences in baseline characteristics, patients with admission anemia had an adjusted OR for all-cause death at 1-month of 1.90 (95% CI, 1.05 to 3.43) and at 1-year of 1.72 (95% CI, 1.00 to 2.93) and for the combined end-point of disability, nursing facility care or death of 2.09 (95% CI, 1.13 to 3.84) and 1.83 (95% CI, 1.02 to 3.27) respectively. The relationship between hemoglobin quartiles and all-cause death revealed a non-linear association with increased risk at extremes of both low and high concentrations. In logistic regression models developed to estimate the linear and quadratic relation between hemoglobin and outcomes of interest, each unit increment in hemoglobin squared was associated with increased adjusted odds of all-cause death [at 1-month 1.06 (1.01 to 1.12; p = 0.03); at 1-year 1.09 (1.04 to 1.15; p < 0.01)], confirming that extremes of both low and high levels of hemoglobin were associated with increased mortality.


CONCLUSIONS
WHO-defined anemia was common in both men and women among patients with acute stroke and predicted poor outcome. Moreover, the association between admission hemoglobin and mortality was not linear; risk for death increased at both extremes of hemoglobin.
Tanne
David
D
Stroke Center, Department of Neurology, Chaim Sheba medical center, Tel- Hashomer, Israel. tanne@post.tau.ac.il
Molshatzki
Noa
N
Merzeliak
Oleg
O
Tsabari
Rakefet
R
Toashi
Maya
M
Schwammenthal
Yvonne
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000209:etiology*; D015331:Cohort Studies; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011336:Probability; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012737:Sex Factors; D020521:Stroke / Q000150:complications* / Q000378:metabolism*
D006454:Hemoglobins