Reported Demographics of Primary Immunodeficiency Diseases in the United States

Abstract

Background: Primary immunodeficiency diseases (PIDDs) are rare genetic disorders impairing immunity. Studies evaluating diagnostic rates of PIDDs in historically marginalized US populations are limited.

Objective: To conduct a scoping review that identifies the extent of race and ethnicity reporting in US-based observational studies of people with PIDDs, and the demographic composition of study populations compared with the broader US population.

Methods: We conducted pragmatic searches of MEDLINE in April 2024 and ultimately included studies dating back 10 years. Results were screened and extracted against prespecified eligibility criteria by a single reviewer. Included data were compared with US census data using χ² tests.

Results: We identified 126 publications publishing observational PIDD studies that report patient characteristics, 62 of which (49%) reported race or ethnicity data. After grouping for data source and PIDD type to avoid overlapping studies, 25 publications were prioritized for extraction. Of these, seven were fully compliant with current Food and Drug Administration-recommended reporting guidelines. The populations of the extracted studies were not statistically representative of the broader US population, with overrepresentation of non-Hispanic White patients.

Conclusions: Primary immunodeficiency disease cohort and other studies inconsistently report demographic data on patient race and ethnicity according to current Food and Drug Administration recommendations. Efforts to improve understanding of the prevalence, characteristics, and diagnostic rates of PIDD in different US populations (as well as differences among study populations and overall US demographics) would likely be facilitated by a greater effort toward comprehensive demographic reporting.

Keywords: Diagnostic disparities; Health care equity; PIDD; Primary immunodeficiency.