Study Reveals Racial Disparities in Immune Tolerance Induction Treatment for Hemophilia

The results of a new study revealed disparities in hemophilia treatment, specifically immune tolerance induction (ITI) for patients with inhibitors. When accounting for racial and ethnic factors, the researchers observed Black and Hispanic patients received ITI less often than White patients.

Professional Nurse Preparing Treatment
Image Credit: Viacheslav Yakobchuk - stock.adobe.com

According to the study published in Research and Practice in Thrombosis and Haemostasis, in racially diverse communities treatment varies throughout racial and ethnic groups, especially with chronic diseases. This cross-sectional investigation aimed to evaluate health care disparities in hemophilia care based on receipt of ITI among patients with hemophilia and an inhibitor in the United States.

The study, conducted between 2013 and 2017, included 614 participants with severe hemophilia A and an inhibitor who entered the CDC Community Counts registry. The participants were aged 5 years or older at the study entry, and all had a history of an inhibitor.

The analysis assessed the proportion of participants receiving ITI, considering race and ethnicity in both bivariable and multivariable analyses. The latter adjusted for demographic and clinical covariates, with unadjusted and adjusted prevalence ratios (aPRs) and corresponding 95% CIs calculated.

Among the 614 participants, 56.4% were non-Hispanic (NH) White, 19.7% were NH Black, 18.4% were Hispanic, and 4.9% were Asian. Overall, 85.2% of participants received ITI. In the bivariable analysis, ITI treatment did not exhibit significant variations across different racial and ethnic groups.

However, the multivariable analysis revealed notable disparities. Upon further investigation, the study accounted for various clinical factors, including driving distance, hemophilia treatment center (HTC) size, and other relevant variables.

In this adjusted analysis, NH Black and Hispanic participants were found to be statistically significantly less likely to have received ITI (aPR, 0.91; 95% CI, 0.84-0.99) relative to NH White participants (aPR, 0.84; 95% CI, 0.75-0.93), with a 9% and 12% difference, respectively. Asian participants, while showing a nonsignificant trend, were also less likely to receive ITI in adjusted analyses.

The study also explored the aggregated data of NH and non-White participants. When grouped together, this demographic category showed a 12% lower likelihood of receiving ITI compared with NH White participants. This finding indicates that racial and ethnic disparities in ITI treatment exist, even after accounting for various clinical factors.

In analyses specifically focused on participants whose inhibitor was detected when they were 5 years or younger, the proportion receiving ITI treatment was higher at 92.9%. However, even in this subgroup, racial and ethnic differences in ITI treatment persisted, indicating that disparities in treatment patterns extend to early detection scenarios.

As the field of hemophilia care continues to advance, future research should delve deeper into the specific factors contributing to racial disparities in ITI treatment, the researchers noted. Specifically, efforts to address these disparities must extend beyond clinical considerations to encompass the social determinants of health, including systemic biases and cultural competence.

“Although the role of ITI may evolve with growing use of emicizumab and the introduction of new hemophilia treatment products, understanding characteristics that influence care, particularly race and ethnicity where physician bias and patient mistrust can occur, will remain relevant and applicable to other complex therapies, including gene therapy,” they wrote.

Reference

Kempton CL, Payne AB, Fedewa SA. Race, ethnicity, and immune tolerance induction in hemophilia A in the United States. Res Pract Thromb Haemost. Published online November 4, 2023. doi:10.1016/j.rpth.2023.102251