[Administrative healthcare data to identify and describe patients with rare diseases: the case of Duchenne muscular dystrophy].

Introduction: Duchenne muscular dystrophy (DMD) is a rare disease that causes a progressive loss of muscle function in males, presenting at the age of two years, and involving respiratory and heart function starting from teenage years. This retrospective observational study has identified patients potentially affected by DMD and described their utilization of healthcare resources and direct healthcare costs charged to the Italian National Healthcare Service (INHS).

Methods: From the Foundation Ricerca e Salute (ReS), through a specific algorithm based only on administrative healthcare data of 5.4 million inhabitants in 2021 (index date), male patients aged <30 years potentially affected by DMD were identified. Comorbidities at baseline, and utilization of healthcare resources and direct healthcare costs charged to the INHS during the year following index date, were described.

Results: In 2021, 120 male patients aged <30 years were identified as potentially affected with DMD (2.2/100,000 inhabitants; 16.1/100,000 males aged <30 years). Chronic airway disease and cardiomyopathy were found in 19.2% and 15.0% of patients, respectively. During follow-up: 41.7% of patients were treated with deflazacort, 2.5% with ataluren and about one third with cardiac drugs; 29.2% and 42.5% were admitted to overnight and day hospitalization, respectively, mainly due to neurological, cardiac, and respiratory diseases; 12.5% accessed the emergency department, mainly for traumatisms and fractures; 70.8% received local outpatient specialist care, half of which were specialist visits, and about 15% cardiac diagnostics. On average, the per capita annual total cost charged to the -INHS was € 6713; ataluren accounted for more than half of this expenditure. After having excluded the dispensation of ataluren during follow-up, the mean per capita total cost was € 2548, more than half of which due to hospitalizations.

Conclusions: This study of administrative data has identified patients potentially affected by DMD, a rare disease, from a large sample of INHS beneficiaries, and assessed their healthcare pathway. This is useful for regulatory purposes and for improved access to emerging innovative therapies.