Impact of Both Ends of the Hemoglobin Range on Clinical Outcomes in Acute Ischemic Stroke

From the Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Korea (Y.H.P., B.J.K., M.H.Y., M.S.J., M.-K.H., S.Y.K., H.-J.B.)
Stroke (Impact Factor: 5.72). 09/2013; 44(11). DOI: 10.1161/STROKEAHA.113.002672
Source: PubMed


Although both ends of the hemoglobin range may negatively influence clinical outcomes in acute ischemic stroke, most studies have examined the linear relationship or focused on the lower end of the range. Furthermore, it is unclear whether hemoglobin concentrations at different time points during hospitalization correlate with clinical outcomes in the same manner.
We identified 2681 consecutive patients with acute ischemic stroke from a prospective stroke registry database and grouped them into hemoglobin concentration quintiles using the following 5 indices: initial, nadir, time-averaged, discharge hemoglobin, and hemoglobin drop. To examine the effect of both ends of hemoglobin range, the third quintile was selected as a reference category except for hemoglobin drop, for which the first quintile was used. As outcome variables, 3-month modified Rankin Scale as an ordinal scale and 3-month mortality were used.
With respect to higher modified Rankin Scale scores, the adjusted odds ratios and 95% confidence intervals of the first quintiles of initial, nadir, time-averaged, and discharge hemoglobin were 1.74 (1.31-2.31), 2.64 (2.09-3.33), 1.81 (1.42-2.30), and 1.65 (1.29-2.13), respectively. The opposite ends of these hemoglobin indices were not significantly associated. The adjusted odds ratio of the fifth quintile of hemoglobin drop (greatest hemoglobin drop) was 2.09 (1.51-2.89). The mortality analysis showed similar results except for initial hemoglobin.
In acute ischemic stroke, poor outcome was related to the lower but not the higher end of the hemoglobin range, regardless of when and how hemoglobin concentrations were measured.

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    ABSTRACT: Objective: To investigate the correlation between anemia and outcome in a large cohort of unselected patients with acute cerebral infarction. Methods: Consecutive acute cerebral infarction patients who were hospitalized were prospectively recruited from August 2010 to November 2013. Eight hundred and fifty-eight patients were enrolled, and the baseline data including age, sex, National Institute of Health Stroke Scale (NIHSS) scores, type of Oxfordshire Community Stroke Project (OCSP: total anterior circulation infarct, partial anterior circulation infarct, posterior circulation infarct and lacunar infarct), serum creatinine, initial hemoglobin level, initial hematocrit level, etc, were recorded. Hemoglobin level and hematocrit level during hospitalization were also recorded. Domestic criteria were used to define if the patient had anemia on admission. Recovery was assessed by modified Rankin Scale (mRS) 180 days after stroke by telephone interview (mRS scores ≥2 reflected good prognosis, and mRS scores >2 reflected unfavorable prognosis). The influence on outcome by anemia on admission, initial hemoglobin level, nadir hemoglobin level, nadir hematocrit level was analyzed by multinomial Logistic regression analysis. Results: Odds ratio of initial hemoglobin level for poor outcome was 1.013 (95% CI 1.001-1.024, P=0.027) with each decrease in hemoglobin of 1 g/dl. Initial anemia (OR=2.417, 95% CI 1.202-4.859, P=0.013) was a independent prognostic factor for mortality; odds ratio of nadir hemoglobin level for mortality was 1.016 (95% CI 1.002-1.030, P=0.026) with each decrease in hemoglobin of 1 g/dl; odds ratio of nadir hematocrit level for mortality was 1.047 (95% CI 1.003-1.093, P=0.037) with decrease in hematocrit of one percentage point. Conclusions: Initial hemoglobin level was a independent prognostic factor for poor outcome in patients with acute cerebral infarction. Anemia on admission, nadir hemoglobin level, nadir hematocrit level were independent prognostic factors for mortality in patients with acute cerebral infarction. (Chinese Clinical Trial Registry (ChiCTR-POC-15006274))
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