Low Hemoglobin Levels at Admission Are Independently Associated with Cognitive Impairment after Ischemic Stroke: a Multicenter, Population-Based Study

Data on the association between hemoglobin (Hb) levels and poststroke cognitive function are limited. We investigated the relationship between Hb concentrations at admission and poststroke cognitive function using a multicenter database. In total, 1081 patients were recruited from seven Chinese medical centers within 6 months after experiencing ischemic stroke. Cognitive status was evaluated with a series of brief neuropsychological tests. A subgroup of 439 patients from a single center was followed up for 4–6 years and was eventually reassessed with a cognitive test. The association between Hb and cognitive impairment was analyzed by multivariable Tobit regression and logistic regression. The mean age of the 920 eligible participants at study entry was 42.5 years; 311 (34%) were women, and all participants were Chinese nationals who lived locally. After adjustment for multiple covariables, Hb levels at admission remained positively associated with poststroke Mini-Mental State Examination (MMSE) scores, with a 0.37-point increase in the MMSE score for every 1-standard-deviation increase in the Hb level. Moreover, an optimal Hb level above 15.0 g/dl was proposed for preventing or alleviating the development of poststroke cognitive impairment in men. After 4–6 years of rehabilitation, the baseline Hb still correlated with MMSE scores. A significant interaction was found between baseline Hb and change in MMSE scores over time, with higher baseline Hb levels predicting faster recovery of global cognitive performance (β, 0.21; 95% confidence interval, 0.03–0.39).These findings warrant further study of anemia as a risk factor for poststroke cognitive impairment.