To the Editor: Dr Wu and colleagues1 reported the results of a large retrospective cohort study to determine the prevalence of abnormal preoperative hematocrit levels and the association of this abnormality with postoperative mortality and cardiac events in elderly patients undergoing noncardiac surgery. They demonstrated a negative association with both low and high preoperative hematocrit levels.
Bellati F, Plotti F, Panici PB. Preoperative Hematocrit Levels and Outcomes After Noncardiac Surgery. JAMA. 2007;298(13):1512-1514. doi:10.1001/jama.298.13.1512-a