Nadine Shehata and colleagues studied this question in a recently published article (abstract) in the August 2013 issue of Transfusion.
This is a single-institution study of 2,102 patients who underwent CABG surgery at the University of Ottawa Hospital. 224 of 2,102 patients were readmitted within 30 days after hospital discharge. The authors collected data on a number of patient and discharge variables.
The leading causes of readmission included infection (24%), heart failure (13%), pulmonary disease (7%), and hemorrhagic disease (?)(7%).
Of the patients discharged, 48% had a discharge Hb between 8 to 10 g/dL and 42% had a discharge Hb between 10 to 12 g/dL.
Predischarge Hb was not a significant independent prognostic predictor of 30-day readmission due to all causes, readmission due to cardiac causes, or 30-day mortality.
Factors that were associated with increased 30-day admission rates included higher co-morbidity score, leg and sternal wound infections, and post-op renal failure.
These data support the concept that anemia is an adaptive response and that even moderate anemia at the time of discharge is well-tolerated, at least as measured by 30-day hospital readmission rate. Moreover, it supports restrictive transfusion practices in these patients. This paper is important for hospital transfusion committees, cardiovascular surgeons, anesthesiologists, and transfusion service physicians to consider with regard to blood utilization management.