Incidence, correlates, and outcomes of acute, hospital-acquired anemia in patients with acute myocardial infarction

Abstract

Background: Anemia is common among patients hospitalized with acute myocardial infarction and is associated with poor outcomes. Less is known about the incidence, correlates, and prognostic implications of acute, hospital-acquired anemia (HAA).

Methods and results: We identified 2909 patients with acute myocardial infarction who had normal hemoglobin (Hgb) on admission in the multicenter TRIUMPH registry and defined HAA by criteria proposed by Beutler and Waalen. We used hierarchical Poisson regression to identify independent correlates of HAA and multivariable proportional hazards regression to identify the association of HAA with mortality and health status. At discharge, 1321 (45.4%) patients had HAA, of whom 348 (26.3%) developed moderate-severe HAA (Hgb <11 g/dL). The incidence of HAA varied significantly across hospitals (range, 33% to 69%; median rate ratio for HAA, 1.13; 95% confidence interval, 1.07 to 1.23, adjusting for patient characteristics). Although documented bleeding was more frequent with more severe HAA, fewer than half of the patients with moderate-severe HAA had any documented bleeding. Independent correlates of HAA included age, female sex, white race, chronic kidney disease, ST-segment elevation myocardial infarction, acute renal failure, use of glycoprotein IIb/IIIa inhibitors, in-hospital complications (cardiogenic shock, bleeding and bleeding severity), and length of stay. After adjustment for GRACE score and bleeding, patients with moderate-severe HAA had higher mortality rates (hazard ratio, 1.82; 95% confidence interval, 1.11 to 2.98 versus no HAA) and poorer health status at 1 year.

Conclusions: HAA develops in nearly half of acute myocardial infarction hospitalizations among patients treated medically or with percutaneous coronary intervention, commonly in the absence of documented bleeding, and is associated with worse mortality and health status. Better understanding of how HAA can be prevented and whether its prevention can improve patient outcomes is needed.

Figure 1

Independent correlates of hospital acquired anemia

Figure 2

Variation in the Incidence of Hospital-acquired Anemia Across Hospitals Figure 2: Variation in the incidence of hospital-acquired anemia across TRIUMPH hospitals enrolling > 20 patients.

Figure 3. 12-month Kaplan-Meier mortality estimates

Figure 3A - 12-month Kaplan-Meier mortality estimates comparing those with no anemia, mild HAA, moderate HAA and chronic anemia. Figure 3B – 12-month Kaplan-Meier mortality estimates comparing HAA patients with documented inpatient bleeding vs. HAA patients without documented bleeding episodes.

Figure 4. 12-month unadjusted and adjusted Mortality among patients with mild HAA, moderate-severe HAA and chronic anemia

Unadjusted and adjusted 12-month mortality (reference category=no anemia)

Figure 5. Association between mild HAA, moderate-severe HAA and chronic anemia with physical functioning across time over 12 months of follow-up

Repeated measures health status comparing SF-12 PCS scores of patients with mild HAA, moderate-severe HAA and chronic anemia after controlling for baseline SF-12 PCS score to no anemia. Results presented as points on SF-12 PCS (95% confidence interval).