Association of high serum β2-microglobulin levels with poor functional outcomes in patients with acute ischemic stroke: A cohort study

We evaluated the association between serum β2-microglobulin (β2M) levels and prognosis in patients with acute ischemic stroke (AIS) and determined whether the association was affected by any clinical variables. This prospective study included 533 patients with AIS who were admitted to the Hospital of Nanhua Affiliated with the University of South China for treatment from June 1, 2021, to July 31, 2022. Using multiple regression modeling, the association between serum β2M levels and poor functional outcomes-which were classified as being modified Rankin Scale scores of 3 to 6 (composite score of death and major disability), 3 to 5 (major disability), and 6 (death)-were assessed 3 months after stroke onset. At the 3-month follow-up assessment, 209 (47.39%) participants had poor functional outcomes: major disabilities in 150 (34.01%) cases and deaths in 59 (13.38%). After adjusting for important covariates, the group with serum β2M levels in the highest quartile had the highest proportion of individuals with modified Rankin Scale scores of 3 to 6 (odds ratio [OR], 3.54; 95% confidence interval [CI], 1.35-9.33), 3 to 5 (OR, 2.95; 95% CI, 1.21-7.16), or 6 (OR, 1.02; 95% CI, 0.29-3.64) compared with the group having serum β2M levels in the lowest quartiles. The risk prediction for the combined outcome of death and major disability improved after incorporating β2M levels into models that included conventional risk factors. Subgroup analysis revealed a significant impact on the association between serum β2M levels and poor functional outcomes only in patients with AIS whose time from onset to hospitalization was <12 hours (P for interaction < .05). Elevated serum β2M levels were associated with poor functional outcomes in patients with AIS, possibly affected by the time from onset to hospitalization.