Longitudinal burden of disease in hypertrophic cardiomyopathy: one-year follow-up of the AFFECT-HCM study

Introduction Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease. However, prospective data on the burden of disease (BoD) remain limited. Baseline results from the AFFECT-HCM cohort reported reduced quality of life (QoL) and increased societal costs among younger (working-aged), symptomatic HCM patients, primarily driven by productivity losses. Purpose This study assesses changes in BoD, defined as QoL combined with healthcare-related costs of HCM patients and genotype-positive/phenotype-negative (G+/P-) individuals after one year. Methods AFFECT-HCM is a multicenter, prospective cohort study conducted in the Netherlands. Participants were stratified based on phenotype (G+/P- subjects, obstructive (oHCM) and non-obstructive HCM (nHCM) patients), and symptomatic status based on the New York Heart Association (NYHA) class (symptomatic= NYHA≥II). After one year, clinical events (including mortality, septal reduction therapy and ICD-implantation), change in NYHA class and medication use were reported. Disease-specific QoL was measured with the Kansas City Cardiomyopathy Questionnaire (KCCQ) and costs were evaluated using the Medical Consumption Questionnaire (iMCQ) and the Productivity Costs Questionnaire (iPCQ). Bootstrapping was performed for the cost data due to the level of skewness observed. Results 479 of the 506 (95%) participants completed the one-year follow-up: 79 G+/P- subjects, 298 nHCM patients and 102 oHCM patients; 38% female and median age 58 years (45-67). Six HCM patients died, including 1 sudden cardiac death among nHCM patients. 18 patients underwent septal reduction therapy, 21 patients (17 nHCM; 4 oHCM) received an ICD. Significant improvement in NYHA class was observed among oHCM patients (P=0.010). Sodium-glucose cotransporter-2 inhibitors (p<0.001 in nHCM) and mavacamten (p=0.0014 in oHCM were initiated more. Completion rate for QoL and cost questionnaires were 86%. KCCQ scores remained stable in G+/P- individuals, nHCM and oHCM patients. However median KCCQ scores significantly improved among symptomatic HCM patients (68 to 76 points, P=0.003), including 53% oHCM and 34% nHCM patients. Societal costs were significantly lower at follow-up compared to baseline in all phenotypes (Table 1a). However, societal costs in NYHA II HCM patients significantly increased (P<0.001), primarily driven by healthcare costs and productivity losses (Table 1b). Conclusion Over a one-year follow-up period, the QoL remained stable, while the societal costs decreased in both G+/P- individuals and HCM patients. A significant reduction in BoD was observed among symptomatic oHCM patients, in particular those classified as NYHA III. This improvement may be related to the effective treatment of oHCM patients with septal reduction therapy and the introduction of mavacamten during the follow-up period.Figure 1.change KCCQ in nHCM/oHCM by NYHATable 1.