Interaction between anemia and renal dysfunction in relation to long-term survival following acute myocardial infarction

Background: Anemia and chronic kidney disease (CKD) adversely affect prognosis following acute myocardial infarction (AMI). We aimed to assess their interaction regarding long-term survival post-AMI. Methods: This is a single-center, retrospective analysis of consecutive AMI survivors. Stratified by admission-time anemia status and CKD grade, as determined by hemoglobin and creatinine levels, the cohort was evaluated for all-cause mortality at 10 years after hospital discharge. Results: A total of 11,395 patients (69.1% males, mean age 65.8 ± 13.9 years, 49.6% with ST elevation MI) were included, of whom 29.9% had anemia and 15.9% - grade 3b or higher CKD. CKD was more advanced among anemic patients and the prevalence of anemia rose as CKD grade increased (p for trend < 0.001). At 10 years, 47.8% of patients died. Notwithstanding differences in baseline characteristics, presentation, and treatment between those with various anemia status and CKD grades, anemia presence (HR 1.40, 95% CI 1.32–1.49, p < 0.001) and increasing CKD grade (HR 1.10, 95% CI 1.02–1.20, p for trend < 0.001) were independently associated with a higher mortality risk. The incremental hazard imposed by either anemia or more advanced CKD was limited to patients with normal renal function and up to grade 3a (in the total cohort and the conservative treatment subgroup) or 4 (in the invasive revascularization subgroup) CKD. The added risk associated with increasing CKD grade also affected non-anemic individuals irrespective of the specific CKD grade. Conclusion: Anemia and more advanced CKD are associated with reduced long-term survival post-AMI, inflicting higher risk when conjoined in lower-grade CKD. Graphical abstract: [Figure not available: see fulltext.].