Ecological study to estimate the prevalence of patients with acid sphingomyelinase deficiency in Spain. PREVASMD study.

Background and objective: Prevalence studies of acid sphingomyelinase deficiency (ASMD) are scarce and different in Spain. The objective of the present study was to determine the estimated prevalence of patients diagnosed with ASMD (types A/B and B) in Spain.

Material and methods: PREVASMD was a descriptive, multicenter, and ecological study involving 21 physicians from different specialties (mainly Internal Medicine, Paediatrics and Hematology), of different autonomous communities, with experience in ASMD management.

Results: Between March and April 2022, specialists were attending a total of 34 patients with ASMD diagnosis, 10 paediatric patients under 18 years of age (29.4%) and 24 adult patients (70.6%). The estimated prevalence of patients (paediatric and adult) diagnosed with ASMD was 0.7 per 1,000,000 inhabitants (95% confidence interval, 95% CI: 0.5-1.0), 1.2 per 1,000,000 (95% CI: 0.6-2.3) in the paediatric population and 0.6 per 1,000,000 inhabitants (95% CI: 0.4-0.9) in the adult population. The most frequent symptoms that led to suspicion of ASMD were: splenomegaly (reported by 100.0% of specialists), hepatomegaly (66.7%), interstitial lung disease (57.1%), and thrombocytopenia (57.1%). According to the specialists, laboratory and routine tests, and assistance in Primary Care were the most relevant healthcare resources in the management of ASMD.

Conclusions: This first study carried out in Spain shows an estimated prevalence of patients of 0.7 per 1,000,000 inhabitants: 1.2 per 1,000,000 inhabitants in the paediatric population and 0.6 per 1,000,000 inhabitants in the adult population.