Underrepresentation and Underreporting of Race/Ethnicity in Systemic Light Chain Amyloidosis NCCN Guidelines
Authors: Reid Katrina , Vojjala Nikhil , Alobaidi Hajir , Houde Christiane A. , Ross Danielle , Caucci Stephen , Zonder Jeffrey A. , Cole Craig Emmitt 
Published: December 2024

Background: The incidence of systemic light chain amyloidosis (SLCA) across racial populations is not well-defined. However, a recent retrospective analysis of 2,416 SLCA patients seen at a single tertiary care referral center reported that 14% were people of color (8% Black, 4% Hispanic, 2% non-Hispanic other) and found prognostically significant racial and ethnic differences in disease presentation, socioeconomic factors, and therapy use (Staron et al.Blood Ca J, 2020). Hematologists refer to The National Comprehensive Cancer Network(NCCN) Systemic Light Chain Amyloidosis Guidelines to inform their treatment strategies for patients with SLCA. Considering the findings above, we reviewed the racial composition of SLCA studies cited as support for the NCCN guidelines to determine the degree to which people of color are included in research informing SLCA treatment guidelines.

Methods: We reviewed the references cited in the “Treatment of Newly Diagnosed SLCA” and “Treated SCLA” sections of the NCCN Systemic Light Chain Amyloidosis Guidelines, version 4.2024. Four reviewers independently analyzed 58 cited studies. We included original articles published in English that described the results of SLCA clinical studies. We excluded studies not specific to amyloidosis, reviews, non-clinical studies, commentaries, editorials, case reports, abstracts, and animal-based studies. The inter-reviewer concordance rate in identifying eligible references was nearly 100%. In cases of non-concordance, all reviewers met and reached a consensus about inclusion through discussion. We then examined the racial composition of al patients enrolled into the studies included in this review.

Results: Forty-one clinical studies including 4977 patients were included in the final analysis; 17 were excluded (9 abstracts, 6 reviews, 1 was not a clinical study and 1 was a duplicate) Among the 41 studies which were included, 22 were retrospective studies, 14 were therapeutic clinical trials, and 5 were prospective observational studies. Median patient age was reported in all except one study. Researchers did not report racial or ethnic demographics in 39 (95.2%) studies. Researchers in only two studies (4.8%) reported the racial/ethnic demographic characteristics of their sample. However, in these two studies, ~90% of participants were White, and the authors did not specify the racial demographics of the remaining 10% of their sample.

Conclusion: The expected outcome of this analysis was that the data would show underrepresentation of minorities in the NCCN guidelines. The actual outcome was that we cannot sufficiently determine the racial demographic characteristics of people included in research informing the NCCN guidelines because researchers rarely reported racial or ethnic characteristics. Further, in the few instances that racial or ethnic demographic information was provided, authors only offered details about White participants and failed to report the characteristics of other groups. Therefore, it is impossible to determine the generalizability and applicability of the SLCA NCCN guidelines to people of color. While minority groups are historically underrepresented in clinical research, the systemic failure to report racial demographic data makes it impossible to determine the extent to which people of color are represented in research forming the basis of the NCCN SLCA guidelines. Researchers must prioritize reporting their racial demographic characteristics and examine how SLCA research applies to the needs and experiences of people of color. We propose that publications describing the results of clinical trials published after 2023 can only be cited in future NCCN guidelines if demographic information regarding race and ethnicity is reported.