The prevalence rate of Duchenne muscular dystrophy (DMD) in the United States has increased, largely due to better treatments that are helping patients live longer, while the number of new cases holds steady, a study reports.
Touted as the first of its kind involving DMD, the Deerfield Institute study, titled “Duchenne Muscular Dystrophy Prevalence in the U.S.: A Novel Incidence-Based Modeling Approach Using System Dynamics,” found that the prevalence — the number of cases — among males 45 or younger was 10 for every 100,000 males, compared with previous estimates of 1.38 for every 10,000 males ages 5 to 24.
In earlier prevalence estimates, the institute said in a press release, a significant number of older patients up to 45 years old had been excluded. Most (64.5%) Duchenne patients are younger than 20. Across all age groups, the prevalence figure was found to be 6.09 for every 100,000 males, translating to roughly 10,015 prevalent cases this year.
Meanwhile, incidence — the rate of newly diagnosed DMD cases — is stable in the United States at 17.24 for every 100,000 live male births, corresponding with roughly 362 incident cases this year. Method-wise, the researchers used a triangular distribution of incidence rates and a sensitivity analysis.
A genetic disease characterized by progressive muscle degeneration and weakness, DMD mostly affects boys.
The study was recently presented at a scientific poster session at the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) annual meeting. ISPOR is widely viewed as the leading educational and scientific organization for health economics and outcomes research.
“We hypothesized that the prevalence of DMD has increased over the past few decades due predominantly to improvements in treatment and care,” said Emma Giegerich, a Deerfield institute epidemiologist who co-authored the study along with Mark Stuntz, a former institute investigator.
“Our incidence-to-prevalence model was built using system dynamics principles and birth-cohort-specific survival curves to get the most accurate picture of the disease landscape and its current burden.”
Results indicate the presence of a larger-than-expected patient population who may benefit from innovative treatments such as targeted gene therapies, she added, prospectively enhancing current or future therapy development programs.
The Deerfield Institute develops and analyzes data to advance understanding of innovation, emerging products, and trends within the healthcare market.