New studies have shed additional light on how convalescent plasma may affect patients with COVID-19, how blood type impacts bleeding risk, the effects of race on cancer-associated thrombosis, and iron deficiency in pregnancy.

These studies were presented as part of the “Best of ASH” session at the 2020 annual meeting of the American Society of Hematology.

Alisa S. Wolberg, PhD, of the University of North Carolina at Chapel Hill, who cochaired the session, reviews these studies with host David H. Henry, MD, in this episode.

Abstract #572: Association of ABO Blood Group with Bleeding Severity in Patients with Bleeding of Unknown Cause. https://bit.ly/2Mc0R2A.

This study, which included 422 patients, indicated that blood group O is overrepresented in patients with bleeding of unknown cause.
Blood group O was associated with a more severe bleeding phenotype, especially oral mucosal bleeding, independent of the levels of von Willebrand factor and factor VIII.
Patients with blood group O had increased clot density, but blood group O didn’t influence thrombin generation or platelet function analysis.
The researchers said these findings are important for better understanding the underlying mechanisms of bleeding in patients who have bleeding of unknown cause.
Dr. Wolberg said this study reframed how people look at bleeding of unknown cause.

Abstract #203: Racial/Ethnic Disparities in Cancer-Associated Thrombosis: A Population-Based Study. https://bit.ly/35Xi5HE.

This study included more than 942,109 cancer patients.
Results showed an independent association between race/ethnicity and the risk of cancer-associated thrombosis.
Asians/Pacific Islanders had a significantly lower incidence of cancer-associated thrombosis, compared with non-Hispanic Whites.
African Americans had a significantly higher incidence of cancer-associated thrombosis versus non-Hispanic Whites.
Racial/ethnic differences were especially prominent when examining pulmonary embolism only.
It’s hard to determine what causes these differences, Dr. Wolberg said. The differences could be explained by underlying biological traits, systemic racism, access to care, and/or the severity of underlying comorbidities, according to the researchers.

Abstract #424: Suboptimal Iron Deficiency Screening in Pregnancy in a High Resource Setting. https://bit.ly/2XYedSA.

The study included data on 47,590 pregnancies in 44,552 women from Ontario.
About 40% of these patients (n = 25,880) had ferritin measurements taken during pregnancy.
Iron deficiency was observed in 52.8% of evaluable pregnancies, and severe iron deficiency was seen in 23.8%.
These findings suggest a ferritin test should be included as part of routine bloodwork at the first prenatal visit, the researchers said.
They also noted that failing to evaluate iron stores in the second and/or third trimester misses the periods of highest iron-deficiency risk, when intravenous iron may be considered.
The researchers said these gaps in care should be addressed by revising guidelines.

Abstract #245: Efficacy of COVID-19 Pathogen-Inactivated Convalescent Plasma for Patients with Moderate-to-Severe Acute COVID-19: A Case-Matched Control Study. https://bit.ly/2XVlulU.

For this study, researchers compared 15 cases and 30 controls, all of whom had COVID-19.
Cases received two units of COVID-19 convalescent plasma (CCP) from different donors.
CCP appeared to improve survival in hospitalized COVID patients, though the difference was not significant.
The 28-day mortality rate was 6.7% among cases and 20.7% in controls (P = .233).
The researchers also found that unselected CCPs have heterogeneous antivirus activity.
Pathogen reduction treatment did not impact antivirus activity.
ADAP, ACE2, RVPN, and COVAM could be used to define activity.
A posttransfusion increase in activity could be detected in some, but not all, patients.
The researchers said more definitive studies are needed.

*Some of the data presented at the meeting differ from data included in the abstracts.

Disclosures:

Dr. Wolberg disclosed relationships with Bristol-Myers Squibb, GlaxoSmithKline, and Takeda. Dr. Henry has no financial disclosures relevant to this episode.

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