An italian real-world analysis of obstructive hypertrophic cardiomyopathy through a large administrative healthcare database

Background The obstructive hypertrophic cardiomyopathy (HCM) is still not curable. Pharmacological treatments and removal of excess cardiac tissue are recommended to manage symptoms. Purpose The study aimed to identify and describe patients with obstructive HCM, from the perspective of the Italian National Health Service (INHS). Methods From the Fondazione ReS (Ricerca e Salute) database (∼5 million inhabitants/year), adults with ≥1 in-hospital main/secondary diagnosis of obstructive HCM (ICD9-CM code: 425.1) and surgical resection between 01/01/2013 and 12/31/2018 (accrual period), were identified. They are characterized by age, sex, comorbidities and implantation of cardiac devices/revascularization performance, at the baseline. Within 2 years from 01/01/2019 (index date), mortality and related causes, pharmacological therapy (obstructive HCM-related drugs, other cardiovascular "CV" and non-CV drugs), overnight hospitalizations due to CV causes of interest (i.e., obstructive HCM/heart failure/coronary artery disease/hypertension/cerebrovascular disease), other CV, and non-CV diagnoses, local outpatient specialist care, and healthcare integrated costs charged to the INHS, were assessed. Results Out of 640 adults (incidence 16.2x100,000 inhabitants; 55% males; mean age 70±14) with obstructive HCM, 60 (9.4%) underwent resection. The most common comorbidities were hypertension (95%), arrhythmia (53%), and dyslipidaemia (50%). A mean of 2 implantations of cardiac devices/revascularizations are performed in 36% (229/640) patients with obstructive HCM. Within 2 years, 65/640 (10.2%) patients died. Among in-hospital deaths (40/65): 2.5% are due to obstructive HCM, 27.5% to CV and 70% to non-CV causes. During follow-up: ∼90% of patients received ≥1 obstructive HCM-related drug (∼80% β-blockers), 88% ≥1 other CV drug and ∼92% ≥1 non-CV medication. Within the 1st and 2nd follow-up years, respectively, 28% and 22% are hospitalized at least once: 14% and 10% for CV causes of interest, ∼2% for other CV events, and 17% and 13% for non-CV causes; on average, ∼10 days of in-hospital stay. From 85% to 80% of patients received ≥1 local outpatient specialist service, during 1st and 2nd years, respectively. On average, the 1st and 2nd year, respectively, the INHS spent per patient €4362 and €3791: pharmaceuticals accounted for 35% and 40% (mostly concomitant drugs), hospitalizations for 57% and 52%, specialist care for 9% and 8% of the total cost. Conclusion Despite the low prevalence of obstructive HCM, this study shows its high overall burden on the INHS, particularly due to concomitant pharmacological treatments and overnight hospitalizations.