Pre-percutaneous coronary intervention hemoglobin as a prognostic indicator for 6-month mortality in acute myocardial infarction patients: a secondary analysis of the Korea Acute Myocardial Infarction Registry National Institutes of Health cohort.

Background: Anemia is frequently observed in patients with acute myocardial infarction (AMI) and is associated with adverse clinical outcomes. However, the exact relationship between hemoglobin levels and long-term prognosis in patients with AMI undergoing percutaneous coronary intervention (PCI) remains unclear. We aimed to assess the correlation between hemoglobin levels and 6-month mortality in patients with AMI undergoing PCI. Elucidating the prognostic significance of hemoglobin levels could facilitate improved risk stratification and inform early clinical decision-making in patients with AMI. Methods: A secondary analysis based on the Korean patients with AMI who had successful PCI was conducted. A total of 13,104 patients with AMI treated from May 2010 to June 2015 at 15 centers funded by a grant from the Korea Centers for Disease Control and Prevention were recruited. Pre-PCI hemoglobin level was the primary exposure, and 6-month all-cause mortality was the primary outcome. Clinical covariates (e.g., demographic factors, cardiovascular risk factors, laboratory data. and in-hospital medications.) were assessed at baseline. Prognostic outcomes were evaluated through multivariate logistic regression and generalized additive models (GAMs), adjusting for key confounders. All patients were followed for six months post-discharge. Results: The study cohort had a mean age of 63.6±12.6 years, and 75.2% were male. The rates of 6-month all-cause death were significantly higher in the lower hemoglobin level group than in the higher hemoglobin level group. After adjustment for clinical covariates, a nonlinear correlation between hemoglobin levels and 6-month all-cause death was observed. With a hemoglobin ≥10.3 g/dL, an increase of 1 g/dL of hemoglobin was associated with a 30% reduction in the risk of death (odds ratio =0.7; 95% confidence interval: 0.6-0.8). However, with a hemoglobin level <10.3 g/dL, the relationship between pre-PCI hemoglobin and mortality at 6 months was not significant (P>0.05). Conclusions: In patients with AMI, a higher pre-PCI hemoglobin level was an independent protective factor against adverse events. A pre-PCI hemoglobin level ≥10.3 g/dL was negatively correlated with 6-month all-cause death. These findings suggest that routine assessment of hemoglobin prior to PCI may enhance early risk stratification and guide individualized management strategies.