When to Transfuse After Hip Surgery?

Ricki Lewis, PhD

December 14, 2011

December 14, 2011 — A more liberal cutoff for transfusion after hip surgery has no appreciable effect on mortality or the ability to walk across a room unassisted, according to results of the Transfusion Trigger Trial for Functional Outcomes in Cardiovascular Patients Undergoing Surgical Hip Fracture Repair. The results are published online December 14 in the New England Journal of Medicine.

Jeffrey L. Carson, MD, from the University of Medicine and Dentistry of New Jersey, New Brunswick, and colleagues tested the hypothesis that untreated anemia endangers people recovering from hip fracture repair. The researchers recruited patients from 47 clinical sites in the United States and Canada from July 19, 2004, through February 28, 2009.

Participants were older than 50 years and had cardiovascular disease (CVD) or risk factors for it. The average age was 81.6 years, and 62.9% of participants had CVD. Hemoglobin had to have fallen below 10 g/dL within 3 days of surgery.

The researchers randomly assigned patients to a "liberal" group (1 unit of packed red cells given at 10 g/dL, with more to maintain that level; n = 1007) and a "restrictive" group (red cells delivered only on symptoms of anemia or hemoglobin < 8 g/dL; n = 1009). More than half of the participants assigned to the restrictive group did not require transfusion.

Patients had hemoglobin measured on hospital days 1, 2, 4, and 7, and were followed-up for 30 days or until discharge, whichever occurred first. Primary outcomes were death or inability to walk 10 feet without human assistance at 60-day follow-up.

Rates of the primary outcome were 35.2% in the liberal group and 34.7% in the restrictive group (liberal: odds ratio, 1.01; 95% confidence interval [CI], 0.84 - 1.22), for an absolute risk difference of 0.5 percentage points (95% CI, −3.7 to 4.7). Rates of in-hospital acute coronary syndrome or death were 4.3% and 5.2%, respectively (absolute risk difference, −0.9%; 99% CI, −3.3 to 1.6), and rates of death on 60-day follow-up were 7.6% and 6.6%, respectively (absolute risk difference, 1.0%; 99% CI, −1.9 to 4.0).

The investigation "found no evidence that maintaining the hemoglobin level above 10 g per deciliter was superior to transfusion for symptoms or maintaining a hemoglobin level of less than 8 g per deciliter," with respect to death or inability to walk unassisted.

"[I]t is reasonable to withhold transfusion in patients who have undergone surgery in the absence of symptoms of anemia or a decline in the hemoglobin level below 8 g per deciliter, even in elderly patients with underlying cardiovascular disease or risk factors," the researchers conclude. Such an approach would conserve the blood supply, they further note.

In an editorial, Paul Barr, PhD, from Queen's University Belfast, Ireland, and Karen Bailie, MD, PhD, from West of Scotland Blood Transfusion Centre, Glasgow, point out that the average difference in hemoglobin levels between the groups was only 1 g/dL, which "may have contributed to the lack of detectable difference in the primary outcome between the two groups." They further caution that the decision to transfuse should consider "a combination of signs, symptoms, and laboratory measures."

Dr. Carson receives grant support from Amgen. One coauthor receives a stipend as president of the Hartford County Medical Association and is an expert witness for the American Academy of Orthopaedic Surgery. One coauthor is a scientific advisory board member for Abbott Laboratories, Alere, Beckman Coulter, Ortho Clinical Diagnostics, and Instrumentation Laboratories, and is a consultant for Abbott Diagnostics, Ortho Clinical Diagnostics, and Instrumentation Laboratories, as well as receiving lecture fees from Abbott Diagnostics and Alere. One coauthors is a board member of Amgen, Novartis, and GlaxoSmithKline and a consultant for Eli Lily, sanofi-aventis, and Amgen, and receives lecture fees from Novartis. The editorialists have disclosed no relevant financial relationships.

N Engl J Med. Published online December 14, 2011. Abstract