ObjectiveTo investigate the influence of hemoglobin level on in-hospital outcome of elderly patients with acute coronary syndrome (ACS).MethodsThis study retrospectively collected 262 elderly patients with ACS in the First Hospital of Tsinghua University from January 2015 to August 2019. Patients were divided into 4 groups according to the hemoglobin level. Patients with hemoglobin level≤121.75 g/L were classified into group A (n=65), patients with hemoglobin level between 121.76 and 132.50 g/L were classified into group B (n=66), patients with hemoglobin level between 132.51 and 144.00 g/L were classified into group C (n=69), and patients with hemoglobin level≥144.01 g/L were classified into group D (n=62). The primary endpoints of this study were in-hospital major adverse cardiovascular events, including all-cause death, reinfarction, acute or subacute stent thrombosis and cardiac arrest. Logistic regression analysis was used to explore the effect of hemoglobin on the in-hospital prognosis of elderly patients with ACS.ResultsLogistic regression analysis showed that the odds ratio of hemoglobin level in the major adverse cardiovascular events assessment was 0.971, the 95% confidence interval was (0.946, 0.996) and the P value was 0.024, while the odds ratio of hemoglobin level in the all-cause death assessment was 0.957, the 95% confidence interval was (0.929, 0.987) and the P value was 0.005.ConclusionLow hemoglobin level is a risk factor for in-hospital adverse events in the elderly patients with ACS.