Analysis of Italian Administrative Healthcare Data to Identify Rare Diseases and Describe Their Clinical Burden: The Case of Duchenne Muscular Distrophy

OBJECTIVES: To identify and describe patients with Duchenne Muscular Dystrophy (DMD) in Italy through administrative healthcare data.

METHODS: From the Fondazione ReS (Ricerca e Salute) database, which collects annually Italian administrative healthcare data, male patients aged <30 years with DMD were selected in 2021 (accrual period). The identification was performed through different algorithms: 1) the ataluren dispensation (ATC code: M09AX03) during accrual and/or 7-year look-back periods; 2) the assignment of the disease waiver code from fee related to muscular dystrophies (RFG080) within 7 years of age; 3) the presence of the disease waiver code RFG080 in 2021 together with a previous genetic test performed in local outpatient specialist settings (Italian codes), and/or a persistent (≥3 months) treatment with corticosteroids for systemic use (i.e., prednisolone – H02AB06; prednisone – H02AB07; deflazacort – H02AB13); 4) the admission to hospital/emergency department with diagnosis of hereditary progressive muscular dystrophy (ICD-9-CM code: 359.1) during accrual and/or look-back periods, together with a previous genetic test and/or a persistent treatment with corticosteroids. The index date was considered as the least recent date corresponding to the aforementioned criteria. If identification criteria were traced before 2021, the index date was Jan 01, 2021. Comorbidities relevant for DMD and evaluable through administrative data, and mean age (±standard deviation) were described at baseline.

RESULTS: Starting from 5,407,239 inhabitants in 2021, among 744,064 males aged <30 years, 120 patients with DMD were identified (16.1/100,000). The annual prevalence between 4 and 7 years was 24.1/100,000. Mean age was 13 (±6) years. At least one comorbidity was found in 37.5% patients. The most frequent comorbidities were chronic obstructive airway diseases (19.2% patients), cardiomyopathies (15.0%), osteoporosis (12.5%), and psychotic disorders (8.3%).

CONCLUSIONS: DMD is a rare disease. Its epidemiology and clinical burden can be reliably described through administrative healthcare data, despite the need of different algorithms and proxies.