Letters Section Editor: Jody W. Zylke, MD, Senior Editor.
Author Affiliations: Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada (firstname.lastname@example.org).
In Reply: Drs Patel and Josephson raise 3 important issues in relation to the generalizability of our results beyond the 6 Canadian sites participating in the ARIPI trial: (1) the interaction between storage age and transfusion thresholds, (2) differences in outcomes related to RBC production methods, and (3) the average age of storage duration in the control group.
The potential interaction between transfusion thresholds and storage age is intriguing and deserves further inquiry. We purposely chose a standard care group in the ARIPI trial to reflect current local transfusion and blood bank practice. As such, there was some variability in transfusion threshold practice between sites and a post hoc analysis did not identify appreciable differences in our primary outcome from the more conservative sites compared with the more liberal sites (unadjusted range of mean pretransfusion episode hemoglobin: 8.7-10.7 g/dL).
Fergusson D, Tinmouth A. Storage Age of Red Blood Cells for Transfusion of Premature Infants—Reply. JAMA. 2013;309(6):544-545. doi:10.1001/jama.2012.177442