Clinical and economic outcomes associated with blood transfusions among elderly Americans following coronary artery bypass graft surgery requiring cardiopulmonary bypass.

Background: Blood transfusion occurring during hospitalisation for heart surgery has been shown to be associated with increased morbidity and mortality and with increased time spent in hospital, use of healthcare services, and costs. The objective of this study was to assess how perioperative blood transfusion among adults 65 years and older who underwent coronary artery bypass graft surgery requiring cardiopulmonary bypass in the United States is associated with immediate and longer term clinical and economic outcomes.

Materials And Methods: Using data from a 5% random sample of Medicare patients who underwent their first (within 2 years) coronary artery bypass graft requiring cardiopulmonary bypass procedure in 2005 or 2006, this study estimated associations (hazard ratios and regression coefficients) between transfusion status (received or not) and complications after surgery, serious adverse events, death, and costs using Cox proportional hazard and generalised linear models adjusting for patients' demographic and clinical characteristics.

Results: Adjusted hazard ratios were statistically significant (P<0.05) for risks of complications (1.20), serious adverse events (1.58), and death (1.49). There was also a statistically significantly (P≤0.01) and strong relationship between receiving transfused blood and Medicare payments over the subsequent 45 months following discharge ($5,778 per calendar quarter for those receiving transfusion vs $5,197; all costs are measured in 2011 USD).

Conclusion: Blood transfusion during hospitalisation for coronary artery bypass graft requiring cardiopulmonary bypass was significantly associated with increased long-term post-operative morbidity, mortality, and overall healthcare costs. This study contributes to the evidence demonstrating an association between transfusion and adverse clinical and economic outcomes by using a nationally representative longitudinal cost and utilisation database.