OBJECTIVES: To estimate the diagnosed incidence and prevalence of Duchenne muscular dystrophy (DMD) in France, Germany, Italy, Spain, and the United Kingdom (UK).

METHODS: Diagnosed incidence of DMD was estimated via a system dynamics model based on a triangular distribution of incidence rates identified from a systematic review of the literature. Diagnosed prevalent cases of DMD were calculated using an incidence to prevalence model and age-specific Kaplan-Meier survival data stratified by birth cohort to account for improvements in treatment practices. To calculate the number of diagnosed incident and prevalent cases in 2019, the incidence rate estimate was multiplied by the sum of country-specific male birth estimates starting in 1971. The number of patients still alive in 2019 constituted the diagnosed prevalent population, which was subsequently divided by the sum of the projected 2019 male population in each country to yield the diagnosed prevalence rate.

RESULTS: The diagnosed incidence of DMD was estimated to be 19.8 (95% CI: 15.2, 24.7) per 100,000 live male births, corresponding to approximately 330 incident cases in 2019. The diagnosed prevalence of DMD was found to be 6.52 (95% CI: 5.04, 8.19) per 100,000 male population, corresponding to approximately 10,406 prevalent cases in 2019. The majority (58.2%) of DMD patients are under the age of 20 and approximately 3% live to be between 40-45 years of age. The prevalence of DMD among male population 45 years of age or younger is 12.0 (95% CI: 9.2, 15.0) per 100,000.

CONCLUSIONS: This is the first examination of the prevalence of DMD in these European countries. While the incidence of DMD in these countries has remained stable, the prevalence of the disease has increased in the past decades due to improvements in life expectancy. Additional advancements in treatments may similarly lead to greater longevity of life, thereby further increasing prevalence.