Duchenne and Becker Muscular Dystrophies’ Prevalence in MD STAR<b><i>net</i></b> Surveillance Sites: An Examination of Racial and Ethnic Differences

Abstract

&lt;b&gt;&lt;i&gt;Introduction:&lt;/i&gt;&lt;/b&gt; Previous studies indicated variability in the prevalence of Duchenne and Becker muscular dystrophies (DBMD) by racial/ethnic groups. The Centers for Disease Control and Prevention’s (CDC) Muscular Dystrophy Surveillance, Tracking, and Research network (MD STAR&lt;i&gt;net&lt;/i&gt;) conducts muscular dystrophy surveillance in multiple geographic areas of the USA and continues to enroll new cases. This provides an opportunity to continue investigating differences in DBMD prevalence by race and ethnicity and to compare the impact of using varying approaches for estimating prevalence. &lt;b&gt;&lt;i&gt;Objective:&lt;/i&gt;&lt;/b&gt; To estimate overall and race/ethnicity-specific prevalence of DBMD among males aged 5–9 years and compare the performance of three prevalence estimation methods. &lt;b&gt;&lt;i&gt;Methods:&lt;/i&gt;&lt;/b&gt; The overall and race/ethnicity-specific 5-year period prevalence rates were estimated with MD STAR&lt;i&gt;net&lt;/i&gt; data using three methods. Method 1 used the median of 5-year prevalence, and methods 2 and 3 calculated prevalence directly with different birth cohorts. To compare prevalence between racial/ethnic groups, Poisson modeling was used to estimate prevalence ratios (PRs) with non-Hispanic (NH) whites as the referent group. Comparison between methods was also conducted. &lt;b&gt;&lt;i&gt;Results:&lt;/i&gt;&lt;/b&gt; In the final population-based sample of 1,164 DBMD males, the overall 5-year prevalence for DBMD among 5–9 years of age ranged from 1.92 to 2.48 per 10,000 males, 0.74–1.26 for NH blacks, 1.78–2.26 for NH whites, 2.24–4.02 for Hispanics, and 0.61–1.83 for NH American Indian or Alaska Native and Asian or Native Hawaiian or Pacific Islander (AIAN/API). The PRs for NH blacks/NH whites, Hispanics/NH whites, and NH AIAN/API/NH whites were 0.46 (95% CI: 0.36–0.59), 1.37 (1.17–1.61), and 0.61 (0.40–0.93), respectively. &lt;b&gt;&lt;i&gt;Conclusions:&lt;/i&gt;&lt;/b&gt; In males aged 5–9 years, compared to the prevalence of DBMD in NH whites, prevalence in NH blacks and NH AIAN/API was lower and higher in Hispanics. All methods produced similar prevalence estimates; however, method 1 produced narrower confidence intervals and method 2 produced fewer zero prevalence estimates than the other two methods.

Characteristics of Clinical Trial Participants with Duchenne Muscular Dystrophy: Data from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet)

“…The observation that non-Hispanic blacks and Hispanics had a lower participation rate than non-Hispanic whites is consistent with observations in other diseases [27]. We note that although it was observed that non-Hispanic blacks have a lower prevalence of DMD than non-Hispanic whites [21,24], in this study we determined the rate of participation among identified patients, so the findings cannot be explained by this diagnostic discrepancy. Many explanations were proposed for discrepancies in trial participation by race or ethnicity [26,27].…”

“…MD STARnet is a population-based public health surveillance program of nine muscular dystrophies, including dystrophinopathies, funded by the Centers for Disease Control and Prevention. Details about MD STARnet were published previously [19][20][21][22][23][24]. For this study, retrospective active surveillance data were collected by six sites: Colorado (CO), Iowa (IA), North Carolina, Piedmont region (NC), South Carolina (SC), Utah (UT), and New York's 21 western counties (wNY).…”

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

“…Another possible explanation for the delay in initial evaluation among non-Hispanic black males could be differences in gene frequency or gene expression. DMD prevalence has been shown to vary across racial/ethnic groups in the USA [20, 22]. Further, there are genetic modifiers known to modulate the DMD phenotype [37, 38], and there may be others still undiscovered.…”

“…MD STAR ne t is a multisite population-based surveillance system funded by the Centers for Disease Control and Prevention that identifies and follows individuals diagnosed with DBMD. The surveillance methodology has been described previously [18-22]. Briefly, data collection was initiated in 2004 at 4 sites (Arizona [AZ], Colorado [CO], Iowa [IA], and 12 counties in Western New York [wNY]); two additional sites were added in 2006 (Georgia [GA], Hawaii [HI]).…”

“…MD STARnet is a multisite population-based surveillance system funded by the Centers for Disease Control and Prevention that identifies and follows individuals diagnosed with DBMD. The surveillance methodology has been described previously [18][19][20][21][22] The MD STARnet case identification and data abstraction approach have been described in detail previously [18,19,23]. In short, cases were screened for cohort eligibility (resident of MD STARnet site, eligible cohort birth date, and diagnosis prior to cohort end date) using International Classification of Diseases, Ninth Revision ICD-9 (ICD-9-CM), code 359.1 and International Classification of Diseases, Tenth Revision (ICD-10), code G71.0, from neuromuscular clinics, private practices, and hospitals.…”