Frequency and clinicoeconomic impact of delays to definitive diagnosis of obstructive hypertrophic cardiomyopathy in the United States.

AIMS: The diagnostic history in the years leading up to the definitive diagnosis of patients with obstructive hypertrophic cardiomyopathy (HCM) has not been studied. METHODS: Patients with a delay in the definitive diagnosis of obstructive HCM from January 2009 to March 2019 were identified in the US IBM MarketScan Commercial and Medicare Supplemental Databases if they had an alternative diagnosis indicating a misdiagnosis during the 24 months before the definitive obstructive HCM diagnosis. Resource use and costs associated with the delay were estimated during the same period. RESULTS: Of 3,888 eligible patients with obstructive HCM, 59.5% had a delay in definitive diagnosis. Patients received a mean of 4.0 misdiagnoses before the definitive obstructive HCM diagnosis, most of which were other cardiovascular conditions. Consequently, 15.7% of patients may have received inappropriate treatment. Approximately 78.4% of patients visited a cardiologist (mean 4.7 visits) before the definitive obstructive HCM diagnosis. Additionally, 26.8% and 32.1% of patients had an inpatient and emergency room visit, respectively. Annualized healthcare costs associated with the delay were $4,379 per patient. LIMITATIONS: The current study used administrative claims data for a commercially insured population. Therefore, the results may not be generalizable to other populations (e.g. those insured by Medicare or Medicaid and the uninsured). Like other database studies, the current study may have suffered from miscoding or undercoding, which may have caused misclassification of patients. Owing to insufficient data, the study could not evaluate all potential consequences of a delay in definitive diagnosis. CONCLUSIONS: Most patients with obstructive HCM had a delay of ≤ 2 years before receiving the definitive diagnosis. The diagnostic journey involved multiple potential misdiagnoses, predominantly cardiovascular, as well as a substantial clinical and economic burden on patients and the healthcare system.

Clinical Outcomes, Resource Utilization, and Treatment Over the Disease Course of Symptomatic Obstructive Hypertrophic Cardiomyopathy in the United States.

We sought to describe the clinical outcomes, resource utilization, and treatment options for patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM) over the course of their disease. Adults with obstructive HCM who were symptomatic were identified from the IBM MarketScan Commercial and Medicare supplemental database (January 2009 to March 2019). The index date was the initial obstructive HCM diagnosis date. Patients were required to have ≥12-month continuous eligibility before and after the index date. Incidence rates (IRs) and cumulative risk of cardiovascular events, healthcare resource utilization, and pharmacotherapy were assessed after index and compared with matched controls. Among 4,617 eligible patients with obstructive HCM, 2,917 (63.2%, mean age 60, 47.2% women) were symptomatic at index date. The most common cardiovascular events were atrial fibrillation/flutter (IR:1.421 per person-year [PPY], heart failure (IR: 0.895 PPY), and dyspnea (IR:0.797 PPY). Patients incurred higher resource use with frequent tests and monitoring, hospitalizations (0.454 PPY), and emergency room visits (0.611 PPY). The use of pharmacotherapy increased from 61.2% in the 6-month preindex period to 83.9% in the 6-month postindex period and remained stable after diagnosis. These events ranged from 3 to over 60-fold higher compared with controls, with the largest difference observed in arrhythmic events. The majority of patients were symptomatic at the time of obstructive HCM diagnosis, resulting in significantly increased cardiovascular complications and frequent disease monitoring after diagnosis versus controls. In conclusion, healthcare resource utilization was substantial, and these findings suggest a higher clinical and economic burden over the disease course among patients with symptomatic obstructive HCM, despite current treatment.

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.

Projecting the Long-term Clinical Value of Mavacamten for the Treatment of Obstructive Hypertrophic Cardiomyopathy in the United States: An Assessment of Net Health Benefit.

PURPOSE: The aim of the study was to project the long-term net health benefits of mavacamten for the treatment of symptomatic obstructive hypertrophic cardiomyopathy (HCM) in the United States. METHODS: A Markov model with 4 mutually exclusive health states (New York Heart Association [NYHA] functional classes I, II, and III/IV and death) was developed to project the life-years (LYs) and quality-adjusted life-years (QALYs) over a lifetime horizon for patients with symptomatic obstructive HCM receiving mavacamten with or without ß-blocker (BB) or calcium channel blocker (CCB) monotherapy or placebo with or without BB or CCB monotherapy. The model simulated a patient cohort with a starting age of 59 years and 41% women. Transition probabilities across NYHA functional classes were estimated using data from the Phase III Clinical Study to Evaluate Mavacamten (MYK-461) in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy (EXPLORER-HCM) and the EXPLORER long-term extension (EXPLORER-LTE) cohort from the Long-term Safety Extension Study of Mavacamten in Adults who Have Completed MAVERICK-HCM or EXPLORER-HCM (MAVA-LTE) trial and were extrapolated after week 30. The mortality risks of NYHA functional class I were assumed to be the age- and sex-specific mortality risks of the US general population. The mortality risks for NYHA class II and III/IV were estimated using those for class I in conjunction with the relative mortality risks derived using patients with obstructive HCM from a large real-world registry. Health state utilities for each treatment were estimated from EXPLORER-HCM. Both LYs and QALYs were aggregated over a lifetime for each treatment arm, discounted at 3% annually, and compared between the 2 arms. Sensitivity analyses were conducted to evaluate the robustness of the model findings. FINDINGS: Over a lifetime, treatment with mavacamten with or without BB or CCB monotherapy was associated with 3.67 incremental LYs compared with placebo with or without BB or CCB monotherapy (13.00 vs 9.33 LYs). Compared with individuals in the placebo group, patients in the mavacamten group were projected to spend 6.17 additional LYs in NYHA functional class I and 0.04 and 2.46 fewer LYs in NYHA functional classes II and III/IV, respectively. With utilities incorporated, mavacamten with or without BB or CCB monotherapy was associated with 4.17 additional QALYs compared with placebo with or without BB or CCB monotherapy (11.74 vs 7.57 QALYs). In the sensitivity analyses, incremental benefits ranged from 1.55 to 6.21 LYs and from 2.48 to 6.19 QALYs across the scenarios. IMPLICATIONS: This model projected substantial net health benefits associated with mavacamten for symptomatic obstructive HCM owing to improved patient survival and quality of life. The projected QALY gain underscored the likely long-term clinical value of mavacamten in symptomatic obstructive HCM.

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

AIMS: Obstructive hypertrophic cardiomyopathy (oHCM) is a disease of the cardiomyocyte in which dynamic left ventricular outflow track obstruction may lead to heart failure, valvular disease, and sudden death. Little is known about healthcare resource utilization (HRU) and costs associated with oHCM. This study investigated the clinical and economic burden of oHCM in patients with or without symptoms associated with oHCM. METHODS: We used the US IBM MarketScan Commercial and Medicare Supplemental database to identify patients with oHCM (January 2009-March 2019). Control patients without cardiomyopathy were matched to each patient with oHCM based on age, sex, region, and index year (3:1 ratio). One-year HRU and cost data were compared between all oHCM, symptomatic oHCM, and asymptomatic oHCM subgroups, and their respective controls. RESULTS: Among 11,401 eligible patients with oHCM (mean age 57 years, 42% female), 5,667 (50%) were symptomatic (23% chest pain, 57% dyspnea, 29% fatigue, 17% syncope). oHCM was associated with significant increases in all-cause hospitalizations, hospital days, outpatient visits, and total healthcare costs (mean ± standard deviation: $26,929 ± 77,720 vs. $6,808 ± 25,712, p<.001) compared with matched controls. These differences were driven mainly by the clinical and economic burden of symptomatic oHCM, which was associated with significant increases in 1-year hospitalization rates (38.0 vs. 6.9%), hospital days (3.7 ± 9.9 vs. 0.4 ± 3.0), and total healthcare costs ($43,586 ± 103,756 vs. $6,768 ± 27,618; all p<.001). Adjustment for comorbidities had minimal impact on these differences. LIMITATIONS: The use of claims data relies on International Classification of Diseases (ICD-9 and ICD-10) diagnosis codes, which might be inaccurate. Only commercially insured patients were included. CONCLUSION: In a real-world population, oHCM was associated with substantial increases in HRU and incremental costs of ∼$20,000/year when compared with matched controls-a difference that increased to ∼$35,000/year among symptomatic patients. Further studies are warranted to understand the potential impact of specific therapies on HRU and the economic burden of oHCM.

PLAIN LANGUAGE SUMMARYObstructive hypertrophic cardiomyopathy (oHCM) is a medical condition in which the heart muscle becomes abnormally thick and can cause partial blockage of blood flow out of the heart. Some patients experience symptoms (such as shortness of breath, chest pain, and fatigue) from this condition while others do not. Little is known about the healthcare resource utilization (HRU) and costs associated with oHCM, and if there are any differences between patients with oHCM who experience symptoms versus those who are asymptomatic. Therefore, we performed a study to investigate the clinical and economic burden of oHCM in patients with or without symptoms associated with oHCM. Based on insurance claims data, ∼50% of all patients with diagnosed oHCM are symptomatic. Symptomatic patients experience nearly 8 times as many hospitalizations and cost the healthcare system >$35,000 per year more than matched controls. In contrast, asymptomatic patients with oHCM have a much smaller difference in HRU and costs (∼$3,600/year) compared with matched controls. The results of this study suggest that effective therapies for oHCM may provide economic value, even if the impact of therapy is limited solely to the relief of symptoms.