ABO blood groups do not predict progression of traumatic intracranial hemorrhage

Impact of ABO blood group on mortality in trauma patients: A systematic review

BACKGROUND

Haemorrhage is a significant cause of death in trauma patients. There is evidence that individuals with blood group O have higher rates of non-traumatic haemorrhage. It has been suggested that blood group O may be associated with higher mortality in trauma, however existing evidence is limited and conflicting.

OBJECTIVE

A systematic review was conducted to evaluate the impact of ABO blood group on mortality in trauma patients.

METHODS

MEDLINE via OVID, the Cochrane library and grey literature were searched to identify studies investigating the effect of ABO blood group on mortality of trauma patients admitted to hospital. PRISMA guidelines were followed throughout, study quality was assessed using CASP checklists and certainty of evidence was evaluated using GRADE. Meta-analysis was precluded by significant study heterogeneity.

RESULTS

180 relevant records were screened and seven studies met inclusion criteria, representing 12,240 patients. Two studies found that there was a higher mortality in blood group O compared to other ABO groups. Included studies had substantial variability in methods and population. Study quality was variable with certainty of evidence rated as very low.

CONCLUSIONS

There is insufficient evidence to definitively establish an association between mortality and ABO group in trauma patients. In an age of increasingly individualised care, there is a need to determine the existence and cause for any association through further studies across multiple settings, trauma mechanisms and populations.

ABO blood type and functional neurological outcome in patients with severe traumatic brain injury

BACKGROUND

The ABO blood system has been involved in the pathogenesis of several diseases, including coagulopathy and bleeding complications. In trauma patients, blood type A has been associated with acute respiratory distress syndrome, and recently, blood type O has been associated with all-cause mortality. The purpose of this study was to assess the association between ABO blood types and long-term functional outcomes in critically ill patients with severe traumatic brain injury (TBI).

METHODS

We conducted a single-center, retrospective, observational study including all patients admitted to the intensive care unit with severe TBI (defined as a Glasgow Coma Scale score of ≤8) between January 2007 and December 2018. Patient characteristics and outcomes were extracted from a prospective registry of all intubated patients admitted to the intensive care unit for TBI. ABO blood types were retrospectively retrieved from patient medical records. The association between ABO blood type (A, B, AB, and O) and unfavorable functional outcome (defined by a Glasgow Outcome Scale score between 1 and 3) 6 months after injury was assessed in univariate and multivariate analysis.

RESULTS

A total of 333 patients meeting the inclusion criteria were included. There were 151 type O (46%), 131 type A (39%), 37 type B (11%), and 12 type AB patients (4%). No significant differences in baseline demographic, clinical, or biological characteristics were observed between blood types. The prevalence of unfavorable outcome was significantly different between the four groups. After adjustment for confounders, blood type O was significantly associated with unfavorable outcome at 6 months (odds ratio, 1.97; confidence interval [1.03-3.80]; p = 0.042). The prevalence of coagulopathy or progressive hemorrhagic injury was not statistically different between blood types ( p = 0.575 and p = 0.813, respectively).

CONCLUSION

Blood type O appears to be associated with unfavorable long-term functional outcome in critically ill patients with severe TBI. Further studies are needed to detail the mechanism underlying this relationship.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Mortality and outcomes by blood group in trauma patients: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

Blood group O contains lower levels of factor VIII and von Willebrand factor. Higher incidence of bleeding among group O is reported in multiple contexts. Results of studies vary regarding outcomes stratified by blood group in trauma. We systematically reviewed the literature for outcomes related to blood group in trauma patients. Meta-analysis of studies evaluating mortality related to blood group was performed.

MATERIALS AND METHODS

The PubMed and Embase databases were searched for studies analysing relationships between blood group and outcomes in trauma patients. Preferred Reporting Items in Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. We synthesized outcomes data related to blood group. Meta-analysis compared mortality rates between group O and non-O patients.

RESULTS

Inclusion criteria were met by 13 studies. Statistically significant differences by blood group were reported in 3 of 10 (30%) studies evaluating mortality, 2 of 3 (66.7%) evaluating mortality from haemorrhage and 2 of 9 (22.2%) evaluating transfusion requirement. Meta-analysis was performed on seven studies evaluating mortality (total n = 11,835). There was significant heterogeneity among studies (I²  = 86%, p < 0.00001). No difference was found in mortality between group O and non-O patients (relative risk = 1.21, 95% confidence interval = 0.89-1.64, p = 0.23).

CONCLUSION

Existing literature does not consistently demonstrate a mortality difference between trauma patients with O and non-O blood groups. High variability in the methods and results among studies limits this conclusion, and further research is needed to delineate under what circumstances blood group may influence outcomes.

Is Low-Titer Group O Whole Blood Truly a Universal Blood Product?

BACKGROUND

Whole blood was historically transfused as a type-specific product. Given recent advocacy for low-titer group O whole blood (LTOWB) as a universal blood product, we examined outcomes after LTOWB transfusion stratified by recipient blood groups.

STUDY DESIGN

Adult trauma patients receiving prehospital or in-hospital transfusion of LTOWB (November 2017 to July 2020) at a single trauma center were prospectively evaluated. The patients were divided into blood type groups (O, A, B, and AB). Major complications and survival to 30 days were compared. Univariate analyses among blood groups were followed by purposeful regression modeling, reflecting 6 variables of significance: male sex, White race, injury severity, arrival lactate, arrival systolic blood pressure, and emergency department blood products.

RESULTS

Of 1,075 patients receiving any LTOWB, 539 (50.1%) were Group O, 340 (31.6%) were Group A, 150 (14.0%) were Group B, and 46 (4.3%) were Group AB. There were no statistically significant differences in demographics, injury severity, hemolysis panels, prehospital vitals, or resuscitation parameters (all p > 0.05). However, arrival systolic pressure was lower (91 vs 102, p = 0.034) and lactate was worse (5.5 vs 4.1, p = 0.048) in Group B patients compared to other groups. While survival and most major complications did not differ across recipient groups, acute kidney injury (AKI) initially appeared higher for Group B. Stepwise regression did not show a difference in AKI rates. This analysis was repeated in patients receiving only component products. Group B again showed no significantly increased risk of AKI (13%) compared to other groups (O 7%, A 7%, AB 5%; p = 0.091).

CONCLUSIONS

LTOWB appears to be a safe product for universal use across all blood groups. Group B recipients arrived with worse physiologic values associated with hemorrhagic shock whether receiving LTOWB or standard component products.

ABO and RhD blood group are not associated with mortality and morbidity in critically ill patients; a multicentre observational study of 29 512 patients

Background

The ABO and RhD blood group represent antigens on the surface of erythrocytes. The ABO blood group antigens are also present on multiple other cells. Interestingly, previous studies have demonstrated associations between the blood group and many types of disease. The present study aimed to identifying associations between the ABO blood group, the RhD blood group, and morbidity and mortality in a mixed cohort and in six pre-defined subgroups of critically ill patients.

Methods

Adult patients admitted to any of the five intensive care units (ICUs) in the Scania Region, Sweden, between February 2007 and April 2021 were eligible for inclusion. The outcomes were mortality analysed at 28– and 90–days as well as at the end of observation and morbidity measured using days alive and free of (DAF) invasive ventilation (DAF ventilation) and DAF circulatory support, including vasopressors or inotropes (DAF circulation), maximum Sequential Organ Failure Assessment score (SOFAmax) the first 28 days after admission and length of stay. All outcomes were analysed in separate multivariable regression models adjusted for age and sex. In addition, in a sensitivity analysis, five subgroups of patients with the main diagnoses sepsis, septic shock, acute respiratory distress syndrome, cardiac arrest and trauma were analysed using the same separate multivariable regression models.

Results

In total, 29,512 unique patients were included in the analyses. There were no significant differences for any of the outcomes between non-O blood groups and blood group O, or between RhD blood groups. In the sensitivity analysis of subgroups, there were no differences in mortality between non-O blood groups and blood group O or between the RhD blood groups. AB was the most common blood group in the COVID-19 cohort.

Conclusions

The ABO and RhD blood group do not influence mortality or morbidity in a general critically ill patient population.