medwireNews: A liberal red blood cell transfusion strategy is no better than a restrictive strategy for reducing the risk for an unfavorable neurological outcome 6 months after traumatic brain injury, the HEMOTION trial has found.
However, there were potential benefits for conducting transfusion at a higher threshold of hemoglobin for several patient-reported measures of functional independence and quality of life after 6 months. Nonetheless, Alexis Turgeon (CHU de Québec-Université Laval Research Center, Canada) and colleagues write in The New England Journal of Medicine that “confidence intervals were not adjusted for multiple testing,” and so “firm conclusions may not be drawn.”
Standard practice for the treatment of anemia in traumatic brain injury has shifted toward transfusion at a lower threshold of hemoglobin than previously used, but “there are concerns regarding potential harms of a restrictive transfusion strategy in these patients,” they say.
The study participants were over 18 years of age (mean 48.7 years) and had acute moderate or severe traumatic brain injury, with a score of 3–12 out of a possible 15 points on the Glasgow Coma scale (GCS), where lower scores signify a lower level of consciousness. They all had anemia, signaled by a hemoglobin level of 10 g/dL or lower.
The patients were randomly assigned to receive red blood cell transfusions in intensive care units (ICUs) based on a liberal (n=369) or restrictive (n=367) strategy, with transfusions initiated when patients had hemoglobin levels of 10 g or below, and 7 g or below, respectively.
Most of the participants were men (72.7%) and the majority were White, at 70.7% and 74.9% of those in the liberal-strategy and restrictive-strategy groups, respectively. A total of 73.2% had a severe traumatic brain injury and the median GCS motor score was 4 points in both groups.
The median hemoglobin level at baseline was 10.8 g and 8.8 g/dL in the liberal-strategy and restrictive-strategy groups, respectively.
After 6 months, the investigators found no significant difference between the liberal strategy and restrictive strategy in terms of the proportion of patients meeting the primary endpoint of an unfavorable outcome at 6 months, at 68.4% and 73.5%, respectively. This outcome was defined as scores of 3 points and lower, 4 points and lower, or 5 points and lower on the Glasgow Outcome Scale–Extended (GOS-E), depending on the patient’s corresponding prognosis at baseline – worst, intermediate, or best. The GOS-E is a measure of disability and recovery ranging from 1 point (death) to 8 points (a full return to normal life).
The findings were consistent when patients with the worst, intermediate, and best predicted prognoses were considered separately, as well as for age, sex, and different severities of traumatic brain injury. The researchers also found no differences in the mortality rates between the two treatment groups at 6 months, at 26.8% with the liberal strategy and 26.3% with the restrictive strategy.
Among surviving patients, those managed using the liberal strategy, versus the restrictive strategy, had a median 4.34-point improvement on the Functional Independence Measure (119 vs 115 points), which ranges from 18 to 126 points; a 5.19-point improvement in median scores on the 100-point Euro-Qol visual analog scale (70 vs 60 points); and a 0.06-point better score on the Euro-Qol five-dimension, five-level utility index (0.74 vs 0.64), which ranges from −0.59 to 1.00 points. However, none of the differences were significant.
“Although mortality is important to consider, critically ill patients with traumatic brain injury and their caregivers may place greater value on other, patient-centered outcomes, since most survivors will live with severe neurologic deficits and various levels of dependency,” write the authors.
Turgeon et al found that both groups had the same rate of venous thromboembolic events, at 8.4%, although more patients in the liberal-strategy group experienced acute respiratory distress syndrome than in the restrictive-strategy group, with respective rates of 3.3% and 0.8%.
The authors note that some trials have used invasive monitoring of brain-tissue oxygenation to improve clinical outcomes in these patients. By contrast, “our trial focused on transfusion thresholds driven by hemoglobin measurement, which offers a pragmatic approach applicable across various ICU settings, irrespective of brain monitoring or resources available within health care systems,” they say.
The investigators acknowledge limitations to the trial, including the fact that they recruited only patients with anemia, which selects a population with more severe traumatic brain injury and increases the baseline risk for an unfavorable outcome.
They add: “Detection of small treatment effects becomes more challenging as the baseline risk increases.”
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