Clinical and economic burden of obstructive hypertrophic cardiomyopathy in the United States

Differences in Healthcare Resource Use and Cost by Pharmacotherapy Among Patients with Symptomatic Obstructive Hypertrophic Cardiomyopathy: Real-World Analysis of Claims Data

BACKGROUND

For symptomatic obstructive hypertrophic cardiomyopathy (oHCM), limited evidence exists on healthcare resource utilization (HRU) and cost for patients with symptomatic oHCM by treatment categories. We evaluated whether HRU and costs vary by initial treatment in symptomatic oHCM.

METHODS

This is a retrospective study of medical and pharmacy claims from 2016 to 2021 to identify (per International Classification of Disease Tenth Revision diagnosis codes) adult patients in the USA with symptomatic oHCM. Patients included in the study cohort were required to be treatment naïve (≥ 12 months' activity before first treatment) and symptomatic (fatigue, chest pain, syncope, dyspnea, heart failure, or palpitations within 3 months of index date). Patients were grouped by first index treatment [beta blocker (BB), calcium channel blockers (CCB), disopyramide, combination therapy], and HRU and costs [per person per year (PPPY), in USD] by initial treatment were reported.

RESULTS

Among 7334 patients with symptomatic oHCM, initial treatment included BB (65.8%), CCB (21.1%), disopyramide (1.2%), or BB + CCB (11.9%). Overall, 87.2% were prescribed monotherapy. Outpatient visits were the main driver of all-cause HRU (mean 11.5 PPPY), and varied by initial treatment (BB: 11.0, CCB: 10.5, disopyramide: 7.2, combination therapy: 12.1). All-cause urgent care visits were more frequent than inpatient visits (means: 5.4 and 0.83 PPPY, respectively). All-cause incurred costs were $46,628 PPPY overall and varied by treatment (BB: $47,029, CCB: $42,124, disopyramide: $27,007, combination therapy: $54,024).

CONCLUSIONS

In this large, US-based cohort of patients with symptomatic oHCM, initial therapy was most commonly BB and CCB monotherapy. Costs and HRU were high for most patients, but greater for those treated initially with combination therapy.

An evidence review and gap analysis for obstructive hypertrophic cardiomyopathy

BACKGROUND

Patients with obstructive hypertrophic cardiomyopathy (oHCM) have a substantial humanistic, clinical, and economic burden due to the array of symptoms and complications associated with the disease. The objective of this review was to identify key evidence gaps related to oHCM, specifically in Europe, North America, and Japan.

METHODS

A targeted literature review was conducted using PubMed to identify English-language studies published between 2012 and 2022 assessing patients with HCM/oHCM in France, Germany, Italy, Spain, the United Kingdom (UK), the United States (US), Canada, and Japan. Outcomes of interest were epidemiology, natural history, pathophysiology, management, and clinical, economic, and humanistic burden. Identified studies were assessed qualitatively to characterize evidence gaps.

RESULTS

Among 2,262 abstracts and 531 full-text articles screened, 178 articles were included from PubMed searches. An additional 16 unique studies were identified via a supplemental Google Scholar search initially conducted in January 2023 and updated in July 2024. Disease natural history, pathophysiology, and management were well documented globally. Significant evidence gaps were noted for the epidemiology, treatment, and burden of oHCM. Although multiple US studies were identified on the clinical, economic, and humanistic burden of oHCM, and one clinical burden study was found for Japan, there was a lack of evidence for France, Germany, Italy, Spain, the UK, and Canada.

CONCLUSIONS

Major evidentiary gaps exist for the epidemiology, treatment, and burden of oHCM. Future research should address these gaps, with a specific focus on generating real-world evidence for Canada and European countries that will support the evaluation of emerging therapies in these regions.

Prevalence and Predictors of Readmissions in Patients With Hypertrophic Cardiomyopathy and Atrial Fibrillation/Flutter

Atrial fibrillation/flutter (AF) is the most common dysrhythmia in patients with hypertrophic cardiomyopathy (HCM). Unexplained left ventricular hypertrophy and left ventricular outflow tract obstruction are integral components of HCM pathology which can cause increased left atrial pressure and atrial myopathy contributing to the substrate for AF. We aimed to determine the impact of AF on hospital readmissions in patients with HCM. We conducted a retrospective analysis using the 2015 to 2019 Nationwide Readmission Database to analyze the effect of AF on 30-day readmission and causes of 30-day readmission in patients with HCM. We also determined the hospital, patient, and procedure-specific independent predictors of readmission in patients with HCM and AF. Of 191,235 index HCM hospitalizations, 81,390 (42.6%) had a secondary diagnosis of AF. A total of 16.9% of patients with HCM and AF were readmitted within 30 days as compared with 14% of HCM patients without AF. The presence of AF was independently associated with a higher risk of all-cause 30-day readmission (hazard ratio [HR] 1.21, 95% confidence interval [CI] 1.17 to 1.25, p <0.001). The foremost etiology of 30-day readmission in HCM patients with AF was hypertensive heart and chronic kidney disease with heart failure, whereas the foremost etiology of 30-day readmission in HCM patients without AF was sepsis. Interventions aimed toward AF management (electrical cardioversion: adjusted HR 0.91, 95% CI 0.82 to 1.01. p = 0.074, AF ablation: HR 0.92, 95% CI 0.74 to 1.13, p = 0.409, Watchman procedure: HR 1.50, 95% CI 0.16 to 14.6, p = 0.725) during index admission did not significantly impact the 30-day readmission in HCM patients with AF. Myectomy during index hospitalization (adjusted HR 0.54, 95% CI 0.34 to 0.86, p = 0.010) was most strongly associated with a lower risk of 30-day readmission in HCM patients with AF. In conclusion, in patients hospitalized for HCM, presence of AF was associated with excess risk of 30-day all-cause readmission. Interventions aimed toward HCM management, that is, myectomy rather than interventions aimed toward AF management predicted lower readmission rate in this patient population.

Quality of life and societal costs in patients with dilated cardiomyopathy

AIMS

Dilated cardiomyopathy (DCM) is a major cause of heart failure impairing patient wellbeing and imposing a substantial economic burden on society, but respective data are missing. This study aims to measure the quality of life (QoL) and societal costs of DCM patients.

METHODS AND RESULTS

A cross-sectional evaluation of QoL and societal costs of DCM patients was performed through the 5-level EuroQol and the Medical Consumption Questionnaire and Productivity Cost Questionnaire, respectively. QoL was translated into numerical values (i.e. utilities). Costs were measured from a Dutch societal perspective. Final costs were extrapolated to 1 year, reported in 2022 Euros, and compared between DCM severity according to NYHA classes. A total of 550 DCM patients from the Maastricht cardiomyopathy registry were included. Mean age was 61 years, and 34% were women. Overall utility was slightly lower for DCM patients than the population mean (0.840 vs. 0.869, P = 0.225). Among EQ-5D dimensions, DCM patients scored lowest in 'usual activities'. Total societal DCM costs were €14 843 per patient per year. Cost drivers were productivity losses (€7037) and medical costs (€4621). Patients with more symptomatic DCM (i.e. NYHA class III or IV) had significantly higher average DCM costs per year compared to less symptomatic DCM (€31 099 vs. €11 446, P < 0.001) and significantly lower utilities (0.631 vs. 0.883, P < 0.001).

CONCLUSION

DCM is associated with high societal costs and reduced QoL, in particular with high DCM severity.

The Majority of Participants With Suspected Hypertrophic Cardiomyopathy Documented During Screening Echocardiography Have a Normal Electrocardiogram

BACKGROUND

Patients with hypertrophic cardiomyopathy (HCM) usually have abnormal electrocardiograms consistent with left ventricular hypertrophy (LVH). The goal of this study was to evaluate the prevalence of abnormal ECG findings (LVH, T wave inversion, left bundle branch block, and left atrial enlargement) in participants with suspected HCM detected during screening echocardiography.

METHOD

The Anthony Bates Foundation has been performing screening echocardiography across the United States for the prevention of sudden death since 2001. A total of 682 subjects between the ages of 8 and 71 underwent echocardiographic screening together with ECG documentation. We evaluated the prevalence of abnormal ECG in participants with suspected HCM defined as any left ventricular wall thickness ≥15 mm.

RESULTS

The prevalence of LVH and T wave inversion were higher in HCM subjects as expected [HCM occurred in 23.5% (4/17) vs. 5.6% (37/665), P = 0.002, T wave inversion occurred in 17.6% (3/17) vs. 4.1% (27/664), P = 0.007]. However, despite adding these 2 common ECG abnormalities in this population, the presence of detected abnormal ECG remained less than 25% (23.5% of HCM subjects had LVH or T wave inversion on ECG vs. 8.7% of control, P = 0.036). Left bundle branch block or abnormal left atrium on ECG were not found in any participants with suspected HCM.

CONCLUSIONS

The prevalence of abnormal ECG in the participants with suspected HCM detected during screening echocardiography is less than 25%. This suggests that ECG alone is not a sensitive marker for the detection of HCM.

The prognostic value of peak oxygen uptake in obstructive hypertrophic cardiomyopathy: a literature review to inform economic model development

AIMS

Patients with obstructive hypertrophic cardiomyopathy (oHCM) experience significant clinical burden which is associated with a high economic burden. Peak oxygen uptake (pVO2), measured by cardiopulmonary exercise testing, is used to quantify functional capacity, and has been studied as a primary endpoint in recent clinical trials. This study aimed to gather evidence to consolidate the prognostic value of pVO2 in oHCM and to assess whether it is feasible to predict health outcomes in an economic model based on changes in pVO2.

METHODS

A targeted literature review was conducted in MEDLINE (via PubMed) and Embase databases to identify evidence on the prognostic value of pVO2 as a surrogate health outcome to support future oHCM economic model development. Following screening, study characteristics, population characteristics, and pVO2 prognostic association data were extracted.

RESULTS

A total of 4,687 studies were identified. In total, 3,531 and 538 studies underwent title/abstract and full-text screening, respectively, of which 151 were included and nine of these were in hypertrophic cardiomyopathy (HCM); only three studies focused on oHCM. The nine HCM studies consisted of one systematic literature review and eight primary studies reporting on 27 potentially predictive relationships from a pVO2-based metric with clinical outcomes including all-cause mortality, cardiovascular mortality, sudden cardiac death, transplant, paroxysmal, and permanent atrial fibrillation. pVO2 was described as a predictor of single and composite endpoints, in three and six studies, respectively, with one study reporting on both.

LIMITATIONS

This study primarily uses systemic literature review methods but does not qualify as one due to not entailing parallel reviewers during title-abstract and full-text stages of review.

CONCLUSION

The findings of this study suggest pVO2 is predictive of multiple health outcomes, providing a rationale to use pVO2 in the development of an economic model.

The evolving paradigm and current perception of hypertrophic cardiomyopathy: Implications for management

Recent evidence from imaging and genetic screening studies has clearly shown that hypertrophic cardiomyopathy (HCM) is more common than initially perceived, emphasizing the need to reassess its associated clinical and social burden. While clinical and academic efforts have long been focused on stratification of arrhythmic risk and management of intraventricular obstruction, progression of cardiac dysfunction and heart failure-related complications have emerged as most relevant from the epidemiological standpoint, delineating a major unmet need. Furthermore, a broader perspective of our patients' needs has become central in the care of individuals with HCM, addressing issues that are not strictly clinical but equally important to their wellbeing, such as quality of life, athletic participation, lifestyle and reproductive choices and psychological adaptation to a chronic condition often detected at a young age. The appropriate evaluation and objective assessment of disease burden associated with HCM are increasingly relevant not only to management but also to trial design and evaluation of the efficacy of emerging, targeted treatments. In this review, we discuss the evolving perception of HCM prevalence and natural history, as well as recent acquisitions regarding its true, often under-appreciated socio-economic and clinical burden.

Quality of life and societal costs in hypertrophic cardiomyopathy: protocol of the AFFECT-HCM study

BACKGROUND

Ever since the first description of hypertrophic cardiomyopathy (HCM), the most common genetic cardiac disease, tremendous progress has been made in the evaluation and management of HCM patients, but little attention has been focused on the impact of HCM on societal costs and quality of life (QoL).

AIMS

This paper describes the study protocol for the AFFECT-HCM study into burden of disease (BoD), which aims to estimate health-related QoL and societal costs in HCM patients and genotype-positive phenotype-negative (G+/P-) relatives during a one-year follow-up study, and relate this to the phenotypical HCM expression.

METHODS

A total of 400 Dutch HCM patients and 100 G+/P- subjects will be followed for one year in a prospective, multi-centre, prevalence-based BoD study. Societal costs will be measured via a bottom-up approach using the cost questionnaires iMCQ and iPCQ. For QoL, the generic EQ-5D-5L and disease-specific Kansas City Cardiomyopathy Questionnaire will be used. QoL and societal costs will be compared with phenotype-specific HCM characteristics and other determinants to identify factors that influence BoD. Accelerometry will test the correlation between BoD and physical activity.

CONCLUSION

The AFFECT-HCM study will evaluate the BoD in HCM patients and G+/P- subjects to improve the understanding of the societal and economic impact of HCM.

New Era: Mavacamten for Obstructive Hypertrophic Cardiomyopathy

Obstructive hypertrophic cardiomyopathy results from asymmetric septal hypertrophy, which eventually obstructs the outflow of the left ventricle. Obstructive hypertrophic cardiomyopathy is linked to mutations in genes that encode for sarcomere proteins, including actin, β-myosin heavy chain, titin, and troponin. The mutations lead to structural abnormalities in myocytes and myofibrils, causing conduction irregularities and abnormal force generation. Obstructive hypertrophic cardiomyopathy is a chronic disease that worsens over time, and patients become at higher risk of developing atrial fibrillation, heart failure, and stroke. Up until recently, there were no disease- specific medications for obstructive hypertrophic cardiomyopathy. Nevertheless, the US Food and Drug Administration approved mavacamten on April 28, 2022, for the treatment of symptomatic obstructive hypertrophic cardiomyopathy (New York Heart Association class II to III) in adults to improve functional capacity and symptoms. Its approval was based on data from EXPLORER- HCM and EXPLORER-LTE (NCT03723655). Mavacamten is a novel, first-in-class, orally active, allosteric inhibitor of cardiac myosin ATPase, which decreases the formation of actin- myosin cross-bridges, and thus, it reduces myocardial contractility, and it improves myocardial energetics. It represents a paradigm-shifting pharmacological treatment of obstructive hypertrophic cardiomyopathy. In this review, we describe its chemical and mechanistic aspects as well as its pharmacokinetics, adverse effects and warnings, potential drug-drug interactions, and contraindications.

Clinical Characteristics and Healthcare Resource Utilization among Patients with Obstructive Hypertrophic Cardiomyopathy Treated in a Range of Settings in the United States

Obstructive hypertrophic cardiomyopathy (oHCM) has been studied primarily in comprehensive centers of excellence. Broadening the understanding of patients with oHCM in the general population may improve identification and treatment in other settings. This retrospective cohort study identified adults with oHCM from a large electronic medical record database comprising data from 39 integrated delivery networks (IBM Explorys; observational period: January 2009–July 2019). Clinical characteristics, healthcare resource utilization (HCRU), and outcomes were reported. Of 8791 patients, 53.0% were female and the mean index age was 61.8 years. Cardiovascular drugs prescribed included beta-blockers (80.5%), calcium channel blockers (46.0%), and disopyramide (2.4%). Over time, heart failure, atrial fibrillation, and ventricular arrhythmias increased. Surgical procedures included septal myectomy (22.0%), alcohol septal ablation (0.6%), and heart transplantation (0.3%). Implantable cardioverter defibrillators were present in 11.2% of patients. After initial septal reduction therapy (SRT), HCRU increased and 550 patients (27.7%) required a reintervention. Of the overall group, 2.7% experienced sudden cardiac arrest by end of study. In conclusion, this cohort of patients with oHCM had guideline-recommended drug therapy and procedures. Despite this, heart failure, atrial fibrillation, and ventricular arrhythmias increased, and more than a quarter of patients undergoing SRT required reintervention. These unresolved issues emphasize the unmet need for new, effective therapies for patients with oHCM.

Longitudinal Psychometric Analysis of the Hypertrophic Cardiomyopathy Symptom Questionnaire (HCMSQ) Using Outcomes from the Phase III EXPLORER-HCM Trial

BACKGROUND

Hypertrophic cardiomyopathy (HCM) symptoms include shortness of breath (SOB), fatigue, chest pain, palpitations, dizziness, and fainting. The HCM Symptom Questionnaire (HCMSQ), the only patient-reported outcome instrument designed to specifically measure HCM symptoms, yields four domain scores (SOB, tiredness, cardiovascular symptoms, syncope) and a total score. We evaluated the longitudinal psychometric properties of the HCMSQ using baseline to week 30 data from the phase III EXPLORER-HCM trial (NCT03470545).

METHODS

Test-retest reliability was assessed via intraclass correlation of patients with stable Patient Global Impression of Change (PGIC) and Patient Global Impression of Severity (PGIS) responses. Sensitivity to change was assessed via Spearman correlations with the Kansas City Cardiomyopathy Questionnaire (KCCQ-23) and the EuroQoL visual analogue scale (EQ VAS), and via one-way ANOVA comparing change groups defined on clinical (New York Heart Association [NYHA] class, left ventricular outflow tract [LVOT] gradient, peak oxygen consumption [pVO2]) and patient-reported (PGIS, PGIC) variables. Meaningful change thresholds were established via PGIC/PGIS.

RESULTS

All HCMSQ scores showed strong evidence of test-retest reliability (intraclass correlation coefficient > 0.70). Sensitivity to change was demonstrated with mostly strong/moderate correlations with KCCQ-23 and EQ VAS, and significant differences (p ≤ 0.05) in PGIS, PGIC, pVO2, and NYHA (except tiredness domain) change categories, but not LVOT gradient. Clinically meaningful score reductions were ≥1 point for tiredness and cardiovascular symptoms domains, ≥ 2.5 points for SOB domain, and ≥2 points for total score.

CONCLUSIONS

Results suggest that HCMSQ is fit for purpose in capturing HCM symptoms and may provide evidence of treatment benefit from the patients' perspectives.

Treatment Changes, Healthcare Resource Utilization, and Costs Among Patients with Symptomatic Obstructive Hypertrophic Cardiomyopathy: A Claims Database Study

INTRODUCTION

There is limited evidence on therapies for obstructive hypertrophic cardiomyopathy (HCM), and data regarding treatment patterns and cost are scarce. This study assessed treatment patterns and economic outcomes in patients with symptomatic obstructive HCM.

METHODS

Adults with symptomatic obstructive HCM as per study design and treated with pharmacotherapies [beta blockers (BBs), calcium channel blockers (CCBs), BB + CCB, or disopyramide] or procedures (septal reduction therapy, heart transplantation, implantable cardioverter-defibrillator, and pacemaker implantation) were identified from the IBM® MarketScan® Commercial and Medicare Supplemental database (January 2009-March 2019). Patients had 12-month continuous eligibility before and after (study period) treatment initiation (index treatment). Healthcare resource utilization (HRU), costs, and treatment changes were assessed.

RESULTS

Of the 4883 patients included in the analysis, 85% received pharmacotherapies (BB 52.5%; CCB 11.7%; BB + CCB 17.7%; disopyramide 2.4%) and 15.7% underwent procedures. During the study period, 38, 34, and 100% of all patients had ≥ 1 inpatient stay, emergency room (ER) visit, and outpatient visit, respectively; mean total healthcare costs were US$53,053. Patients undergoing procedures had the highest HRU and costs across groups. Among patients receiving pharmacotherapies, HRU was lowest with BBs and highest with disopyramide. Treatment changes were observed in 43.8% of patients receiving pharmacotherapies.

CONCLUSIONS

Patients experienced high rates of treatment changes, and the economic burden associated with symptomatic obstructive HCM increased as therapy escalated. More effective therapies are needed to stabilize or decrease the economic burden of obstructive HCM.

Healthcare resource utilization and cost of obstructive hypertrophic cardiomyopathy in a US population

Background

There are limited data evaluating all-cause and disease-related healthcare resource utilization (HCRU) and cost of care for patients with obstructive hypertrophic cardiomyopathy (oHCM).

Methods

This was a retrospective study using US longitudinal medical and pharmacy claims data during 2012-2020. Adults with ≥2 oHCM diagnoses were identified, with the first diagnosis date used as the index date. HCRU and costs of care were reported for the year preindex (baseline) and at 1- and 2-year follow-ups.

Results

We identified 1841 patients with oHCM (63 ± 15 years; 52% male). The mean number of hypertrophic cardiomyopathy (HCM)-related outpatient and cardiology visits increased from baseline to 1-year follow-up (2.3 vs. 7.8 and 0.6 vs. 2.2, respectively). At baseline, 8% of patients had ≥1 HCM-related inpatient hospitalization (mean 0.11 visits, 5.4 days length of stay), increasing to 27% postdiagnosis (mean 0.42 visits, 5.9 days length of stay). Total HCM-related costs increased from $5968 to $20,290 at 1-year follow-up, largely driven by inpatient hospitalization costs ($3889 vs. $14,369) and surgical costs ($2259 vs. $7217). The proportion with ≥1 HCM-related prescription increased from baseline (69%; mean fills 5.3) to 1-year follow-up (82%; mean fills 7.8). Pharmacy costs were generally low but also increased ($449 vs. $752).

Conclusions

This benchmark economic dataset for management and evaluation of patients with oHCM shows increased HCM-related costs over a 2-year period after oHCM diagnosis, driven by inpatient hospitalizations and surgical costs. Medication use was high, but costs were low, possibly reflecting use of generic multi-indication drugs for oHCM treatment.