Racial and Ethnic Differences in Timing of Diagnosis and Clinical Services Received in Duchenne Muscular Dystrophy

Abstract

Introduction: Racial/ethnic differences in diagnostic and treatment services have been identified for a range of health conditions and outcomes. The current study aimed to analyze whether there are racial/ethnic differences in the timing of diagnostic testing and treatments for males with Duchenne Muscular Dystrophy (DMD). Methods: Diagnostic and clinical data for male individuals with DMD born during 1990-2010 were analyzed from eight sites (Arizona, Colorado, Georgia, Iowa, Piedmont Region of North Carolina, western New York, South Carolina, Utah) of the Muscular Dystrophy Surveillance Tracking and Research Network (MD STARnet). Seven milestones related to diagnosis/treatment experiences were selected as outcomes. Times to each milestone were estimated and compared by four racial/ethnic groups using Kaplan-Meier estimation and Cox proportional hazard models. Times between initial evaluation or diagnostic testing and later milestones were also compared by race/ethnicity. Results: We identified 682 males with definite or probable DMD of whom 61.7% were non-Hispanic White, 20.5% Hispanic, 10.6% other, and 7.2% non-Hispanic Black. Seven milestone events were studied (initial evaluation, first neurology/neuromuscular visit, diagnosis, corticosteroid treatment first offered, corticosteroid treatment started, first electrocardiogram or echocardiogram, and first pulmonary function testing). The first five milestone events occurred at an older age for non-Hispanic Black individuals compared to non-Hispanic White individuals. Time from diagnosis to first offering of corticosteroids and initiation of corticosteroid therapy was later for Hispanic individuals compared to non-Hispanic White individuals. When accounting for timing of initial evaluation/diagnosis, offering of corticosteroids continued to occur later, but first pulmonary testing occurred earlier, among Hispanic individuals compared to non-Hispanic Whites. No significant delays remained for non-Hispanic Black individuals after accounting for later initial evaluation/diagnosis. Conclusion: We described racial/ethnic differences in ages at selected diagnostic and treatment milestones. The most notable differences were significant delays for five of seven milestones in non-Hispanic Black individuals, which appeared to be attributable to later initial evaluation/diagnosis. Findings for Hispanic individuals were less consistent. Efforts to address barriers to early evaluation and diagnosis for non-Hispanic Black children with DMD may promote more timely initiation of recommended disease monitoring and interventions.

Mathematical modeling of the progression of Duchenne Muscular Dystrophy in San Diego in an era of allele specific oligonucleotide therapy

“…We were concerned that differences in FVC% decline in Hispanic and non-Hispanic boys might have re ected a different level of care. One previous study found that time to initiation of corticosteroid therapy of DMD was later among Hispanic individuals and rst pulmonary testing occurred earlier compared to non-Hispanic whites 30 . However, another study found that the average annual death rate of males with DMD age <40 years were higher in non-Hispanic whites than Hispanic whites 31 .…”

Diagnoses of muscular dystrophy in a veterans health system

“…For example, the MD STARnet study on racial and ethnic differences in timing of diagnosis and clinical services received in Duchenne MD raises awareness of racial and ethnic disparities and could lead to educational efforts and earlier diagnoses in these populations. 19 When conducting surveillance and research on MD, it is important to include VHS as a data source. Mild cases of MD and those of later onset appear to be compatible in some cases with successful completion of military service.…”

“…This can potentially lead to measures that will ultimately improve the quality of life of individuals living with MD. For example, the MD STARnet study on racial and ethnic differences in timing of diagnosis and clinical services received in Duchenne MD raises awareness of racial and ethnic disparities and could lead to educational efforts and earlier diagnoses in these populations 19 . When conducting surveillance and research on MD, it is important to include VHS as a data source.…”

Newborn screening for Duchenne muscular dystrophy: the perspectives of stakeholders

“… 6 For boys with DMD, diagnostic delays have remained unchanged over the past three decades, 7 with late diagnosis persistently noted in ethnic minority groups. 8 For many children, this results in missed opportunities for implementation of standards of care, participation in clinical trials, and access to newly approved dystrophin restoration therapies. Likewise, families lose opportunities for timely genetic counselling and testing.…”