Association of admission anemia with 90-day functional outcomes after acute ischemic stroke

Anemia is common among patients with acute ischemic stroke (AIS), but its association with the full spectrum of poststroke functional outcomes remains incompletely characterized. This study evaluated the association between admission anemia and 90-day functional outcomes after AIS. This secondary analysis used publicly available data from a prospective AIS registry at Seoul National University Hospital, South Korea. Anemia was defined using sex-specific hemoglobin thresholds. The primary outcome was the full ordinal distribution of the 90-day modified Rankin Scale (mRS). Secondary outcomes were mRS scores of 0 to 1, mRS scores of 0 to 2, and 90-day mortality. Partial proportional odds and logistic regression models were used. Fully adjusted models included demographic characteristics, stroke severity, vascular risk factors, premorbid disability, and reduced kidney function, defined as an admission estimated glomerular filtration rate < 60 mL/min/1.73 m². Among 1906 included patients, 738 (38.7%) were women and 508 (26.7%) had anemia. In the fully adjusted partial proportional odds model, anemia was associated with higher odds of severe disability or death, including mRS ≥ 4 vs. 0–3 (OR, 1.604; 95% CI, 1.202–2.142; P =.001), mRS ≥ 5 vs. 0–4 (OR, 1.987; 95% CI, 1.392–2.838; P <.001), and mRS 6 vs. 0–5 (OR, 3.651; 95% CI, 2.236–5.962; P <.001). Anemia was not independently associated with mRS 0 to 1 (OR, 0.812; 95% CI, 0.630–1.047; P =.109) or mRS 0 to 2 (OR, 0.832; 95% CI, 0.628–1.102; P =.200), but remained associated with 90-day mortality (OR, 3.152; 95% CI, 1.903–5.219; P <.001). Moderate and severe anemia showed more consistent associations with adverse outcomes. Admission anemia was associated with worse 90-day functional outcomes after AIS, particularly severe disability and death. Assessment of anemia may help identify patients at higher risk of poor prognosis after AIS.