Cardiovascular outcomes by time-varying New York Heart Association class among patients with obstructive hypertrophic cardiomyopathy: a retrospective cohort study.

Aims: Assess the relationship between New York Heart Association (NYHA) functional class and cardiovascular (CV) outcomes in obstructive hypertrophic cardiomyopathy (HCM).

Materials And Methods: This retrospective cohort study used the Optum Market Clarity database with linked claims and electronic health records. Adults (aged ≥18 years) with obstructive HCM and ≥1 NYHA class assessment after first HCM diagnosis were eligible (selection period: 2007-2021). Thirteen outcomes were assessed following the index date (first documented NYHA class assessment after first HCM diagnosis in the study period): all-cause mortality; first occurrences of all-cause hospitalization; CV-related hospitalization; primary ischemic stroke or transient ischemic attack (TIA); myocardial infarction (MI); deep vein thrombosis (DVT) or pulmonary embolism (PE); and major adverse CV event (MACE); as well as first incident events of atrial fibrillation or flutter; primary ischemic stroke or TIA; heart failure; acute MI; DVT/PE; and a composite endpoint of pacemaker and cardiac resynchronization therapy. Their associations with the index NYHA class were described using the Kaplan-Meier method (mortality) or cumulative incidence functions (other outcomes). Hazard ratios between NYHA class over time and outcomes were evaluated using time-varying Cox models, adjusting for age at first observed HCM diagnosis, sex, and race.

Results: Among 4,631 eligible patients, the mean age was 59 years at the first observed HCM diagnosis (female, 47%; White, 77%). The risks of all outcomes increased with worse (higher) index NYHA class and worsening NYHA class over time. Deterioration in the NYHA class from the index date was associated with increased risks of outcomes.

Limitations: The study population may not be representative of all patients with obstructive HCM in the real world. Documented NYHA classes may not fully reflect the longitudinal variation of NYHA class for each patient.

Conclusions: Worsening NYHA class was associated with increased risks of all-cause mortality and CV outcomes in obstructive HCM.