Erythropoietin for critically ill trauma patients: A missed opportunity?

Vitamin D status is associated with hepcidin and hemoglobin concentrations in patients with severe traumatic injury

BACKGROUND

Severe traumatic injury leads to persistent injury-associated anemia that is associated with hypercatecholaminemia, systemic inflammation, increased hepcidin, and a functional iron deficiency. Vitamin D has been shown to reduce proinflammatory cytokines and hepcidin concentrations. This study aimed to investigate the association of vitamin D status with inflammation, iron biomarkers, and anemia following blunt trauma.

METHODS

A prospective observational cohort study comparing blunt trauma patients (n = 45) with elective hip replacement patients (n = 22) and healthy controls (n = 8) was performed. Bone marrow ferroportin, transferrin receptor, and erythroferrone expression was measured using quantitative polymerase chain reaction (qPCR). Plasma was assessed for systemic inflammation, erythropoietin (EPO), iron regulation, and vitamin D (25-OH) concentrations using enzyme-linked immunosorbent assay. Hemoglobin was measured on the day of discharge.

RESULTS

Compared with hip replacement, trauma patients had higher plasma interleukin-6 (90.1 vs. 3.8 pg/mL), C-reactive protein (6,223 vs. 2,612 ng/mL), and hepcidin (79.3 vs. 21.2 ng/mL) concentrations. Trauma patients had lower vitamin D (25-OH) (12.8 vs. 18.1 ng/mL) and iron (23.5 vs. 59.9 μg/mL) levels compared with hip replacement patients. Despite the higher hepcidin EPO levels, bone marrow erythroferrone expression was increased 69% following trauma.

CONCLUSION

Following elective hip replacement, patients did have anemia and impaired iron homeostasis without a significant change in inflammatory biomarkers, EPO, and vitamin D status. Vitamin D status did correlate with systemic inflammation, iron dysfunction, and persistent injury-associated anemia following severe blunt trauma. Further research is needed to determine whether supplementation with vitamin D in the trauma population could improve the persistent injury-associated anemia.

LEVEL OF EVIDENCE

Prospective study, prognostic, level III.

Meta-Analysis with Trial Sequential Analysis on the Efficacy and Safety of Erythropoietin in Traumatic Brain Injury: A New Paradigm

OBJECTIVE

Erythropoietin (EPO) has been shown to be beneficial in traumatic brain injury (TBI). We have attempted to quantitatively synthesize the findings of current randomized controlled trials (RCTs) in this meta-analysis and analyzed the need for further trials using trial sequential analysis (TSA).

METHODS

A systematic search was performed in PubMed, the Cochrane Library databases, and Google Scholar for RCTs until December 2019 evaluating the role of EPO in patients with TBI. Seven RCTs were finally included in the quantitative analysis. TSA was done to evaluate the need for further studies.

RESULTS

The pooled estimate demonstrated that EPO significantly reduced mortality at 6 months (odds ratio [OR], 0.65; 95% confidence interval [CI], 0.43-0.97; P = 0.04) but not in hospital mortality (OR, 0.84; 95% CI, 0.31-2.32; P = 0.74). There was no significant difference in the rate of favorable outcomes with EPO (OR, 1.58; 95% CI, 0.84-2.99; P = 0.16). The rate of deep vein thrombosis (RD, -0.02; 95% CI, -0.06 to 0.02; P =0.41) was also not found to be significantly different in the 2 groups. TSA showed that the accrued information is insufficient to make any definitive conclusions.

CONCLUSIONS

EPO seems to be beneficial in terms of reducing 6-month mortality, however, its effect on in-hospital mortality, neurologic outcomes, and risk of deep vein thrombosis fails to reach statistical significance. TSA suggests a need for large trials to evaluate the role of EPO in patients with TBI in a more systematic way.

Anemia and Red Blood Cell Transfusion: Advances in Critical Care

Anemia is common in the intensive care unit (ICU), resulting in frequent administration of red blood cell (RBC) transfusions. Significant advances have been made in understanding the pathophysiology of anemia in the ICU, which is anemia of inflammation. This anemia is related to high hepcidin concentrations resulting in iron-restricted erythropoiesis, and decreased erythropoietin concentrations. A new hormone (erythroferrone) has been identified, which mediates hepcidin suppression to allow increased iron absorption and mobilization from iron stores. RBC transfusions are most commonly administered to ICU patients for treatment of anemia. All strategies to reduce anemia in the ICU should be implemented.

Erythropoiesis-stimulating Agents in Critically Ill Trauma Patients: A Systematic Review and Meta-analysis

OBJECTIVE

To perform a meta-analysis of all relevant randomized controlled trials assessing the effect of erythropoiesis-stimulating agents (ESAs) in critically ill trauma patients.

BACKGROUND

ESAs have effects beyond erythropoiesis. The administration of the ESA epoetin alfa to critically ill trauma patients has been associated with a reduction in mortality.

METHODS

We performed a systematic review and meta-analysis with trial sequential analysis. We searched Medline, Medline in Process, and other nonindexed citations, EMBASE, and the Cochrane Database from inception until September 9, 2015, for randomized controlled trials comparing ESAs to placebo (or no ESA).

RESULTS

We identified 9 eligible studies that randomly assigned 2607 critically ill patients after trauma to an ESA or placebo (or no ESA). Compared with placebo (or no ESA), ESA therapy was associated with a substantial reduction in mortality [risk ratio (RR) 0.63, 95% confidence interval (CI) 0.49-0.79, P = 0.0001, I = 0%). In patients with traumatic brain injury, ESA therapy did not increase the number of patients surviving with moderate disability or good recovery (RR 1.00, 95% CI 0.88-1.15, P = 0.95, I = 0%). With the dosing regimens employed in the included studies, ESA therapy did not increase the risk of lower limb proximal deep venous thrombosis (RR 0.97, 95% CI 0.72-1.29, P = 0.78, I = 0%).

CONCLUSIONS

The administration of ESAs to critically ill trauma patients is associated with a significant improvement in mortality without an increase in the rate of lower limb proximal deep venous thrombosis. Given the worldwide public health significance of these findings research to validate or refute them is required.

Erythropoietin in traumatic brain injury (EPO-TBI): a double-blind randomised controlled trial

BACKGROUND

Erythropoietin might have neurocytoprotective effects. In this trial, we studied its effect on neurological recovery, mortality, and venous thrombotic events in patients with traumatic brain injury.

METHODS

Erythropoietin in Traumatic Brain Injury (EPO-TBI) was a double-blind, placebo-controlled trial undertaken in 29 centres (all university-affiliated teaching hospitals) in seven countries (Australia, New Zealand, France, Germany, Finland, Ireland, and Saudi Arabia). Within 24 h of brain injury, 606 patients were randomly assigned by a concealed web-based computer-generated randomisation schedule to erythropoietin (40,000 units subcutaneously) or placebo (0·9% sodium chloride subcutaneously) once per week for a maximum of three doses. Randomisation was stratified by severity of traumatic brain injury (moderate vs severe) and participating site. With the exception of designated site pharmacists, the site dosing nurses at all sites, and the pharmacists at the central pharmacy in France, all study personnel, patients, and patients' relatives were masked to treatment assignment. The primary outcome, assessed at 6 months by modified intention-to-treat analysis, was improvement in the patients' neurological status, summarised as a reduction in the proportion of patients with an Extended Glasgow Outcome Scale (GOS-E) of 1-4 (death, vegetative state, and severe disability). Two equally spaced preplanned interim analyses were done (after 202 and 404 participants were enrolled). This study is registered with ClinicalTrials.gov, number NCT00987454.

FINDINGS

Between May 3, 2010, and Nov 1, 2014, 606 patients were enrolled and randomly assigned to erythropoietin (n=308) or placebo (n=298). Ten of these patients (six in the erythropoietin group and four in the placebo group) were lost to follow up at 6 months; therefore, data for the primary outcome analysis was available for 596 patients (302 in the erythropoietin group and 294 in the placebo group). Compared with placebo, erythropoietin did not reduce the proportion of patients with a GOS-E level of 1-4 (134 [44%] of 302 patients in the erythropoietin group vs 132 [45%] of 294 in the placebo group; relative risk [RR] 0·99 [95% CI 0·83-1·18], p=0·90). In terms of safety, erythropoietin did not significantly affect 6-month mortality versus placebo (32 [11%] of 305 patients had died at 6 months in the erythropoietin group vs 46 [16%] of 297 [16%] in the placebo group; RR 0·68 [95% CI 0·44-1·03], p=0·07) or increase the occurrence of deep venous thrombosis of the lower limbs (48 [16%] of 305 vs 54 [18%] of 298; RR 0·87 [95% CI 0·61-1·24], p=0·44).

INTERPRETATION

Following moderate or severe traumatic brain injury, erythropoietin did not reduce the number of patients with severe neurological dysfunction (GOS-E level 1-4) or increase the incidence of deep venous thrombosis of the lower limbs. The effect of erythropoietin on mortality remains uncertain.

FUNDING

The National Health and Medical Research Council and the Transport Accident Commission.