Hemoglobin nonrecovery following acute myocardial infarction is a biomarker of poor outcome: A retrospective database study

Background Anemia on admission and during hospitalization is associated with poor short and long term prognosis among patients with acute coronary syndrome (ACS). Our objective was to examine the prognostic implications of longitudinal hemoglobin (Hb) levels following a first acute myocardial infarction (AMI). Methods We utilized data obtained from the computerized database of a large community based health care maintenance organization to identify patients who survived for at least 6 months following a first AMI, during the years 2003-2010. Hazard ratios were calculated using Cox proportional regression models with various Hb measurements as dependent variables, and net reclassification improvement (NRI) was applied to evaluate the prognostic usefulness of these Hb measurements. Results Last Hb measurement during a 6-24 month follow-up period was found to have the highest prognostic power. In males, Hb levels below 13 g/dL were gradually associated with a higher risk of events, reaching a HR of 4.13 at Hb levels < 11 g/dL. In females, only Hb levels lower than 11 g/dL were significantly associated with a higher event rate (HR = 2.42, p = 0.003). Hb decrease was significantly associated with an increased risk in both genders, even among non-anemic patients at baseline. Conclusions Anemia and Hb decrement following a first AMI are associated with worse prognosis and elevated risk of combined all cause mortality and recurrent cardiac events.