Serum beta-2 microglobulin predicts mortality after acute coronary syndrome

Abstract

Introduction: We have previously shown that serum beta-2 microglobulin (B2M) is significantly elevated in patients with acute coronary syndrome (ACS) in Hong Kong and is a predictor of all-cause mortality in the United States National Health and Nutritional Examination Survey. In this cohort study, we investigated the relationship between baseline B2M level and mortality in long-term follow-up. Methods: In total, 88 patients with ACS and 79 controls matched for age and sex were recruited from Queen Mary Hospital between September 2015 and May 2016. Serum B2M was measured using a latex-enhanced B2M immunoassay (Siemens Diagnostics, Erlangen, Germany). Patient data up to 15 November 2018 were extracted from the Clinical Data Analysis and Reporting System of the Hong Kong Hospital Authority. Serum B2M levels were compared using analysis of variance with SPSS (Windows version 25.0; IBM Corp, Armonk [NY], United States). Results: Seven patients died (6 in the ACS group) during the follow-up period. The geometric mean of serum B2M level was 3.13 μg/mL (95% confidence interval [CI]=2.14-4.58 μg/mL) in those who died and 1.97 μg/mL (95% CI=1.84-2.11 μg/mL) in those who survived (P=0.001). In the ACS group, the geometric mean serum B2M level was 3.50 μg/mL (95% CI= 2.73-4.49 μg/mL) in those who died and 1.99 μg/mL (95% CI=1.78-2.23 μg/mL) in those who survived (P=0.002). Conclusion: Elevated serum B2M level is associated with higher mortality in patients with ACS. This test is readily available and may help to identify high-risk patients with ACS.