Several Demographic Groups Underrepresented in Clinical Trials of Blood Donation, Blood Transfusion

A review of participant data from clinical trials of blood donation and blood transfusion in the United States demonstrates that various demographic groups are underrepresented in these trials. Researchers reported their findings earlier this month in Transfusion and Apheresis Science.

In this cross-sectional study, investigators analyzed participant sex, race/ethnicity and age data from 38 clinical trials of blood donation and blood transfusion registered with Clinicaltrials.gov. These included seven blood donation trials (with a total of 2,720 participants) and 31 blood transfusion trials (with a total of 9,255 participants).

The investigative team found that, despite mandatory reporting requirements and an established reporting framework, clinical trial researchers frequently failed to report complete demographics of trial participants. While the participant dataset from trial reports were incomplete, 100% of blood donation trials reported sex and age, 71.4% reported race and 42.3% reported ethnicity. Among blood transfusion trials, 100% reported age, 96.8% reported sex, 51.6% reported race and 38.7% reported ethnicity.

The results also suggested that several demographic groups were underrepresented compared with 2019 U.S. census data. Females were underrepresented among blood donation trial participants (28.5%) compared with census data (50.8%). However, female (50.8%) and male participants (49.2%) were equally represented among blood transfusion trial participants. 

White (73.4%) and Asian (6%) participants were overrepresented in blood donation trials compared with 2019 census data (72.5% and 5.5%, respectively) while Black or African American participants (4.3 %) Hispanic or Latino participants (7.7%) were underrepresented (12.7% and 18%, respectively). Representation was lowest for American Indian or Alaska Native participants (0.4%), followed by Native Hawaiian or Other Pacific Islanders (1.8%) and multiracial participants (2.6%).

Among blood transfusion trial participants, representation was highest for White (70.5%) and Black or African American participants (22.4%). Representation was lowest Native Hawaiians or Other Pacific Islanders (0.3%), American Indians or Alaska Natives (0.5%), multiracial participants, (1%), Other race (1.6 %) and Asians (2.4%). Hispanic or Latino participants were underrepresented (8.2%). Furthermore, only 8.3 % of blood transfusion clinical trials open to adults reported the inclusion of adults aged 65 and older.

According to the authors, these gaps in data reporting, particularly for race and ethnicity, must be addressed to instruct equitable enrollment for future trials. “While our findings indicate progress is being made, they demonstrate an opportunity for further introspection and the adoption of patient-focused studies that explore barriers to participation for some underrepresented groups in blood donation- and transfusion-related trials, and appropriate interventions to increase participation in trials among these groups,” the authors concluded.