Association of hemoglobin trend and outcomes in aneurysmal subarachnoid hemorrhage: A single center cohort study

Anemia has been linked to delayed cerebral ischemia (DCI) and worse outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH). However, the association of hemoglobin (Hb) trend and outcomes is not well studied. We investigated predictors of Hb trend and its association with outcomes in patients with aSAH. Our hypothesis was that a negative Hb trend is associated with poorer outcomes independent of Hb values.We conducted a retrospective study of a prospectively collected cohort of consecutive patients with aSAH who were admitted to an academic center (2016-2021). We tested the association of Hb trend and values with measures including DCI and poor functional outcome defined as modified Rankin scale 4-6 at 3 months after discharge. Multiple linear regression analysis was used to identify factors associated with Hb difference from admission to discharge.We included 310 patients with confirmed aneurysmal etiology (mean age 57 years, SD13.6; 62 % female). Greater Hb decrement from admission to discharge was independently associated with higher likelihood of both DCI (OR 1.28 per 1 g/dl decrease in Hb, 95 % CI 1.08-1.47; p = 0.003) and poor functional outcome (OR 1.27 per 1 g/dl decrease in Hb, 1.03-1.53; p = 0.026) independent of any absolute Hb values. Predictors of Hb decrement from admission to discharge were hospital length of stay, Hunt and Hess grades, female sex and age.Greater Hb decrement can be associated with higher likelihood of DCI and poor functional outcome in aSAH. More evidence is needed to use Hb trend to guide transfusion threshold in aSAH patients.