Impact of Sociodemographic Characteristics on Outcomes in Obstructive Hypertrophic Cardiomyopathy

Abstract

Background

Obstructive hypertrophic cardiomyopathy (oHCM) is associated with adverse clinical outcomes. This study aimed to evaluate real‐world clinical outcomes, health care resource use, and health care costs in patients with oHCM stratified by their sociodemographic characteristics.

Methods

This retrospective, noninterventional cohort study from the Optum Market Clarity Integrated Clinical and Claims database included US adults with ≥2 medical claims with a diagnosis code for oHCM (2013–2021). Dependent on outcome measure, follow‐up was variable, fixed 1‐year, or fixed 5‐year. Outcome measures were rate of major adverse cardiovascular events, medication use, HCRU, and health care costs.

Results

The study included 14 744 patients with oHCM (mean±SD age, 61.8 [14.0] years; 7504 [50.9%] female). Female patients had a higher rate of stroke than male patients (6863 versus 4773 per 100 000 patient‐years), and Black patients had a higher rate of heart failure than White patients (31 084 versus 20 603). Patients in the South had a higher rate of heart failure than patients in the Northeast (25 406 versus 18 705). Patients aged 18 to 39 years had more mean±SD HCM‐related ambulatory visits per patient per month (0.41 [0.48]) than older patients (eg, aged 75+, 0.27 [0.35]). Patients in the Midwest had the greatest mean±SD HCM‐related health care costs per month (2071 [6420] USD) versus patients in other regions (eg, Northeast 1440 [3912] USD). Differences between groups were significant (P<0.001).

Conclusions

In patients with oHCM, rate of major adverse cardiovascular events, health care resource use, and health care costs varied substantially between sociodemographic groups. Further studies are required to understand the causes of the observed variation between sociodemographic groups.

Nonstandard Abbreviations and Acronyms

HCM

hypertrophic cardiomyopathy

HCRU

health care resource use

MACE

major adverse cardiovascular events

oHCM

obstructive hypertrophic cardiomyopathy

SRT

septal reduction therapy

USD

US dollars

Clinical Perspective.

What Is New?

• Among patients with obstructive hypertrophic cardiomyopathy, the rate of major adverse cardiovascular events, health care resource use, and health care costs varies substantially between sociodemographic groups.

• Greater inpatient and emergency department costs are incurred by Black patients; clinical and financial outcomes are significantly different between patients receiving Medicaid/Medicare versus commercial insurance and across geographical regions.

What Are the Clinical Implications?

• Sociodemographic characteristics of patients with obstructive hypertrophic cardiomyopathy should be considered in diagnosis and treatment.

Hypertrophic cardiomyopathy (HCM) is a common genetic heart disease characterized by left ventricular hypertrophy out of proportion to hemodynamic loading conditions. Prevalence estimates vary between studies, with an estimated prevalence of HCM of 1 in 500 people based on echocardiographic imaging in the United States and United Kingdom, ¹ whereas recent health care claims studies estimated the prevalence as 1 in 3000 people in the United States and Germany. ² , ³ The 2 major subtypes of HCM, obstructive (oHCM) and nonobstructive, are defined by the presence of resting or provocable left ventricular outflow tract obstruction. ⁴ Population‐based claims data suggest that the prevalence of diagnosed HCM in the United States increased 1.5 fold between 2013 and 2019 to >260 000, largely due to an increase in the number of nonobstructive HCM diagnoses. ⁵

Symptoms of oHCM include dyspnea, fatigue, chest pain, and syncope, leading to reduced quality of life. ⁶ , ⁷ , ⁸ Apart from cardiac myosin inhibitors, guideline‐recommended, standard‐of‐care pharmacotherapies for oHCM do not address the molecular basis of the disease, and patients can require invasive therapies, including septal reduction therapy (SRT, septal myectomy, and alcohol septal ablation). ⁹ However, despite invasive treatments, patients with oHCM may experience adverse clinical outcomes, including atrial fibrillation (AF) and heart failure (HF), due to disease progression. ¹⁰ , ¹¹

Although the clinical profile and management of patients with oHCM have been well described previously, ¹² , ¹³ limited real‐world data are available on clinical outcomes, health care resource use (HCRU), and health care costs in patients with oHCM. ¹⁴ , ¹⁵ , ¹⁶ , ¹⁷ , ¹⁸ Consequently, the association between sociodemographic characteristics such as sex, race, age, geographical region, and payor and patient outcomes is not well understood. Additionally, there are no data regarding the associations between sociodemographic characteristics and patient HCRU and health care costs. The objective of this study was to evaluate real‐world clinical outcomes, HCRU, and health care costs in patients with oHCM, stratified by their sociodemographic characteristics.

METHODS

The data that support the findings of this study were originated by and are the property of Optum, Inc, which has restrictions prohibiting the authors from making the data set publicly available. Requests for data sharing can be submitted to Qiana Amos at Optum (qiana.amos@optum.com).

Study Design and Data Source

This was a retrospective, observational, noninterventional cohort study using data from the Optum Market Clarity Integrated Clinical and Claims database, which comprises US electronic health record (EHR) and administrative claims data. Medical and pharmacy claims data for patients with oHCM were analyzed to assess treatment patterns, HCRU, and costs. Claims and EHR data were used to assess patient demographics, clinical characteristics, and clinical outcomes. As data were deidentified with all personally identifiable information removed, this study was exempt from institutional review board approval.

Study Population

Eligible patients were adults with ≥2 medical claims with a diagnosis code for HCM (International Statistical Classification of Diseases, Ninth Revision [ICD‐9]: 425.1, 425.11 or 425.18; Tenth Revision [ICD‐10]: I42.1 or I42.2) in any position ≥30 days apart during the patient identification period (January 1, 2013, through December 31, 2021). The date of the first oHCM claim was the index date. Patients required continuous enrollment with medical and pharmacy benefits for ≥6 months before and ≥6 months after the index date. Patients with missing age, sex, or unknown geographical region were excluded, as were patients with a claim for Fabry disease or amyloidosis during the study period.

Study End Points

Demographic characteristics were assessed from administrative claims data on the index date and included sex, age, race, payor, and US geographical region. Racial demographic data were self‐identified by patients. Clinical characteristics including Charlson Comorbidity Index, select comorbidities, and diagnosing provider specialty were assessed during the 6‐month baseline period before the index date.

The rate of major adverse cardiovascular events (MACE) was assessed over the variable follow‐up period (period between the index date and the end of variable follow‐up) and fixed 1‐year and 5‐year follow‐up periods. The variable follow‐up period was defined as the period from index HCM diagnosis to death, health plan disenrollment, or study end. MACE outcomes were rates of AF, stroke, HF, ventricular arrhythmia, ventricular tachycardia, ventricular fibrillation, supraventricular tachycardia, stress cardiomyopathy, sudden cardiac arrest, SRT, cardiovascular hospitalization, hospital readmission, and heart transplant. Rates of MACE were determined via assessment of medical claims with an ICD‐9 or ICD‐10 code. All‐cause mortality was assessed based on data from facility claims, diagnosis and procedure codes, and reasons for disenrollment from enrollment records and obituary records. Additional information on how MACE outcomes were defined is provided in Data S1. Medication use and receipt of therapeutic procedures were assessed over the variable follow‐up period and fixed 1‐year and 5‐year follow‐up periods.

HCM‐related HCRU and health care costs were assessed over the variable follow‐up and fixed 1‐year follow‐up periods. HCRU was calculated for ambulatory visits (physician office and hospital outpatient), emergency department (ED) visits, inpatient visits, including associated in hospital length of stay (LOS) and pharmacy use. HCM‐related health care costs were computed as the combined health plan and patient paid amounts. Total costs, pharmacy costs, and medical costs were calculated. Medical costs included subcategories of ambulatory costs (physician office and hospital outpatient), ED costs, inpatient costs, and other medical costs. HCRU and health care costs were determined to be HCM‐related if the patient had a diagnosis code for HCM, or if their claim was for specific HCM treatments (beta blockers, calcium channel blockers [CCBs], disopyramide, SRT, cardioverter‐defibrillator implantation, pacemaker implantation, or heart transplant). ¹⁰

Statistical Analysis

Baseline characteristics were summarized by sociodemographic groups (sex, race, age, payor, geographical region). Time‐to‐event outcomes, including MACE and all‐cause mortality, were evaluated using Kaplan–Meier analyses, with comparisons performed across groups. HCRU data are presented as per‐patient‐per‐month estimates, and health care costs as per‐patient‐per‐month values in 2022 US dollars (USD). ¹⁹ All study outcomes were reported descriptively. Continuous variables were summarized as means±SD and compared using 2‐sample t tests for 2‐group comparisons or ANOVA for comparisons across ≥3 more groups.

RESULTS

Patient Baseline Characteristics

In total 14 744 patients with oHCM met all baseline criteria and were included (Table S1). Of these, 13 426 patients had 1‐year follow‐up data, and 5129 had 5‐year follow‐up data.

Mean±SD age in the overall population was 61.8 (14.0) years. Equal proportions were male (7240, 49.1%) and female (7504, 50.9%). Most patients (10 875, 73.8%) were White, 6251 (42.4%) had commercial insurance, 4947 (33.6%) received Medicare, and 1453 (9.9%) received Medicaid (Table 1). Mean±SD Charlson Comorbidity Index was 1.9 (2.0) among Black patients versus 1.7 (1.9) among Hispanic patients, 1.3 (1.7) among White patients, and 1.1 (1.6) among Asian patients. A higher proportion of patients aged 75+ had coronary artery disease, HF, or hypertension at baseline than patients in other age groups (Table S2). Overall >50% of patients across sociodemographic groups received a diagnostic ECG, <10% received cardiac magnetic resonance imaging, <2% received genetic testing and <1% received a cardiopulmonary exercise test during baseline (Table 1). Higher proportions of patients receiving Medicare or Medicaid had baseline comorbidities than patients with commercial insurance, and higher proportions of patients in the South had baseline comorbidities than patients in other regions (Table S3).

Table 1.

Baseline Demographic and Clinical Characteristics

Characteristic		Total (N=14 744)
Age, y, mean±SD		61.8 (14.0)
Sex, n (%)	Female	7504 (50.9)
	Male	7240 (49.1)
Race and ethnicity, n (%)	White	10 875 (73.8)
	Black	2898 (19.7)
	Asian	355 (2.4)
	Hispanic	616 (4.2)
Payor type, n (%)	Commercial	6251 (42.4)
	Medicare	4947 (33.6)
	Medicaid	1453 (9.9)
	Other	77 (0.5)
	Unknown/missing	2016 (13.7)
US geographical region, n (%)	Northeast	3905 (26.5)
	Midwest	6350 (43.1)
	South	3345 (22.7)
	West	1144 (7.8)
Charlson Comorbidity Index, mean±SD		1.4 (1.8)
Baseline comorbidities, n (%)	Coronary artery disease	4101 (27.8)
	Hypothyroidism	1886 (12.8)
	Heart failure	2526 (17.1)
	Hypertension	9709 (65.9)
	Type 2 diabetes	3731 (25.3)
	Obesity	2949 (20.0)
Diagnosing provider specialty, n (%)	Cardiologist	7960 (54.0)
	Cardiovascular surgery	99 (0.7)
	Primary care physician	1742 (11.8)
	General practice	785 (5.3)
	Others	2893 (19.6)
Diagnostic test, n (%)	ECG	8192 (55.6)
	Echocardiogram	6007 (40.7)
	Cardiac magnetic resonance imaging	464 (3.2)
	Cardiopulmonary exercise test	89 (0.6)
	Computed tomography scan	59 (0.4)
	Positron emission tomography scan	1326 (9.0)
	Genetic testing	158 (1.1)

Most patients were prescribed a medication at baseline. A higher proportion of White patients received beta blockers than patients in other racial and ethnic groups, whereas a higher proportion of Black patients received CCBs. Similarly, a higher proportion of White patients received any therapeutic procedure than patients in other racial and ethnic groups (Table S4). A smaller proportion of patients with commercial insurance received a prescribed medication at baseline versus patients receiving Medicare or Medicaid. Additionally, a smaller proportion of patients with commercial insurance received any therapeutic procedure versus patients receiving Medicare (Table S5).

Clinical Outcomes

Major Adverse Cardiovascular Events

Mean±SD follow‐up time in the overall study population was 43.1 (28.4) months. During variable follow‐up, compared with male patients, female patients had higher rates of stroke (rate per 100 000 patient‐years: 6863 versus 4773), HF (25 697 versus 19 056), and all‐cause mortality (3361 versus 2253), P<0.001 for all comparisons (Figure 1). Black patients versus White patients had a higher rate of stroke (8980 versus 5093), HF (31 084 versus 20 603), and cardiovascular hospitalization (17 633 versus 13 441), whereas Black patients had a lower rate of AF (11 963 versus 17 652), P<0.001 for all comparisons (Figure 1). The rate of HF was ∼3 times higher in the 75+ age group versus patients in the 18 to 39 age group and twice as high versus patients in the 40 to 54 age group, P<0.001 for all comparisons (Figure 1). Compared with those who were commercially insured, patients receiving Medicare had higher rates of AF (21 228 versus 13 942), stroke (8397 versus 3507), and HF (30 812 versus 16 024), P<0.001 for all comparisons (Figure 1). Patients in the South versus patients in the Northeast had a higher rate of HF (25 406 versus 18 704). Patients in the Midwest had a higher rate of cardiovascular hospitalization than patients in other regions, P<0.001 for all comparisons (Figure S1). Kaplan–Meier plots for all‐cause mortality by demographic characteristics during variable follow‐up are shown in Figure 2 and Figure S2, and Kaplan–Meier plots for cardiovascular hospitalization are shown in Figure S3.

Figure 1. Rates of select MACE outcomes and all‐cause mortality per 100 000 patient‐years during variable follow‐up by (A) sex, (B) race and ethnicity, (C) age, and (D) payor.

*P<0.05 across 2‐sample t tests: (A) vs male patients; (B) vs White patients; (C) vs patients aged 75+, (D) vs patients with commercial insurance. AF indicates atrial fibrillation; HF, heart failure; MACE, major adverse cardiovascular events; and PY, patient‐years.

Figure 2. Kaplan–Meier plots of all‐cause mortality by (A) sex, (B) race and ethnicity, (C) age, and (D) payor during variable follow‐up.

During 1‐year follow‐up, female patients compared with male patients had higher rates of stroke (12.0% versus 9.4%) and HF (35.9% versus 30.9%) and a lower rate of sudden cardiac arrest (1.4% versus 1.8%). All between‐group comparisons were significant (P<0.05). Rates of MACE over 1‐year follow‐up by sex, race and ethnicity, and age are reported in Table S6 and over 5‐year follow‐up in Table S7. During 1‐year follow‐up, patients in the West versus the Northeast had a higher rate of all‐cause mortality (13.7% versus 9.0%; Table S8). This difference was also observed over the 5‐year follow‐up period (33.8% versus 20.9%; Table S9). Similarly, patients receiving Medicare had a greater rate of sudden cardiac arrest (6.1% versus 4.0%) and all‐cause mortality over the 5‐year follow‐up period compared with those who were commercially insured (46.7% versus 13.0%; Table S9). All between‐group comparisons were significant (P<0.001).

Prescribed Medication Use and Receipt of Therapeutic Procedures

During variable follow‐up, female patients versus male patients had a higher rate of any prescribed medication (rate per 100 000 patient‐years: 708 845 versus 651 181; P<0.001). Conversely, female patients versus male patients had a lower rate of any therapeutic procedure (10 570 versus 13 700; P<0.001) and implantable cardioverter‐defibrillator implantation (4346 versus 7152; P<0.001; Table S10). Black patients versus White patients had a higher rate of any prescribed medication (943 647 versus 631 007), CCB prescriptions (71 928 versus 25 979), and anticoagulant prescriptions (23 339 versus 21 001), P<0.001 for all comparisons. In contrast, Black patients had a lower rate of beta blocker prescriptions (73 471 versus 116 500; P<0.001), any therapeutic procedure (7942 versus 13 378; P<0.001), SRT (1238 versus 3509; P<0.001), and implantable cardioverter‐defibrillator implantation (5031 versus 5864; P<0.05; Table S10). Patients receiving Medicare versus patients with commercial insurance had a higher rate of any prescribed medication (815 776 versus 574 680), CCB prescriptions (40 577 versus 24 356), and anticoagulant prescriptions (22 650 versus 18 997), P<0.001 for all comparisons. Patients receiving Medicare versus patients with commercial insurance had a lower rate of any therapeutic procedure (10 472 versus 13 775), SRT (1918 versus 4014), and implantable cardioverter‐defibrillator implantation (4036 versus 6866), P<0.001 for all comparisons (Table S11).

During 1‐year follow‐up, male patients had a higher rate of antiarrhythmic prescriptions (21.0% versus 16.7%) and a higher rate of implantable cardioverter‐defibrillator implantation (13.7% versus 7.8%). Prescribed medication use and therapeutic procedure receipt over 1‐year follow‐up by sex, race and ethnicity, and age are reported in Table S12 and over 5‐year follow‐up in Table S13. During 1‐year follow‐up, patients in the Midwest versus patients in the Northeast had a higher rate of anticoagulant drug prescriptions (36.0% versus 27.8%; Table S14). This difference was also observed over the 5‐year follow‐up period (56.2% versus 47.2%; Table S15). Patients receiving Medicaid versus patients with commercial insurance had a higher rate of CCB prescriptions over the 5‐year follow‐up period (70.0% versus 49.1%), and a lower rate of any therapeutic procedure (32.1% versus 41.1%; Table S15). All between‐group comparisons were significant (P<0.001).

HCM‐Related Health Care Resource Use

Male patients had more ambulatory visits than female patients during variable follow‐up (per‐patient‐per‐month; [SD], 0.35 [0.41] versus 0.31 [0.40]), whereas female patients had a longer mean LOS per month (mean days, 0.30 [1.27] versus 0.24 [1.16]; Table 2). Data on ambulatory visits by office and outpatient visits are shown in Table S16. Black patients had more mean inpatient admissions per month than White, Hispanic, or Asian patients. Patients aged 18 to 39 had more ambulatory visits, fewer inpatient admissions, and a shorter mean LOS than older age groups. Patients receiving Medicare experienced a longer mean LOS than patients with commercial insurance (0.41 days [1.56] versus 0.16 days [0.82]) and fewer ambulatory visits (0.28 [0.37] versus 0.38 [0.43]). Patients in the West had more ambulatory visits per month than patients in other regions. All between‐group comparisons were significant (P<0.05).

Table 2.

HCM‐Related HCRU by Demographic Group During Variable Follow‐Up, PPPM

Demographic group	Ambulatory visits, mean±SD	ED visits, mean±SD	Inpatient admissions, mean±SD	LOS, mean±SD, d	Pharmacy use, mean±SD
Sex
Female	0.31 (0.4)*	0.02 (0.07)	0.03 (0.07)*	0.30 (1.27)*	0.56 (0.44)
Male	0.35 (0.41)*	0.02 (0.08)	0.02 (0.06)*	0.24 (1.16)*	0.55 (0.44)
Race and ethnicity
White	0.35 (0.42)*	0.02 (0.06)*	0.02 (0.07)*	0.27 (1.23)*	0.54 (0.43)*
Black	0.26 (0.37)*	0.04 (0.12)*	0.03 (0.07)*	0.31 (1.21)*	0.61 (0.46)*
Asian	0.30 (0.31)*	0.01 (0.04)*	0.01 (0.03)*	0.17 (1.33)*	0.54 (0.44)*
Hispanic	0.33 (0.41)*	0.02 (0.07)*	0.02 (0.04)*	0.19 (0.92)*	0.54 (0.44)*
Age, y
18–39	0.41 (0.48)*	0.04 (0.15)*	0.02 (0.07)*	0.15 (0.64)*	0.54 (0.44)*
40–54	0.36 (0.43)*	0.02 (0.06)*	0.02 (0.05)*	0.16 (0.71)*	0.58 (0.44)*
55–64	0.35 (0.40)*	0.02 (0.07)*	0.02 (0.06)*	0.22 (1.09)*	0.61 (0.48)*
65–74	0.30 (0.40)*	0.02 (0.08)*	0.02 (0.07)*	0.30 (1.41)*	0.51 (0.40)*
75+	0.27 (0.35)*	0.02 (0.06)*	0.03 (0.09)*	0.45 (1.63)*	0.52 (0.41)*
Payor†
Commercial	0.38 (0.43)*	0.01 (0.04)*	0.02 (0.05)*	0.16 (0.82)*	0.56 (0.44)*
Medicare	0.28 (0.37)*	0.02 (0.08)*	0.03 (0.08)*	0.41 (1.56)*	0.52 (0.40)*
Medicaid	0.29 (0.42)*	0.06 (0.15)*	0.03 (0.08)*	0.34 (1.33)*	0.70 (0.53)*
Geographical region
Northeast	0.29 (0.33)*	0.01 (0.05)*	0.02 (0.06)*	0.23 (1.28)*	0.56 (0.46)
Midwest	0.34 (0.42)*	0.03 (0.09)*	0.03 (0.08)*	0.30 (1.29)*	0.56 (0.44)
South	0.35 (0.41)*	0.02 (0.08)*	0.02 (0.06)*	0.27 (1.11)*	0.56 (0.43)
West	0.37 (0.53)*	0.01 (0.05)*	0.02 (0.05)*	0.22 (0.79)*	0.53 (0.42)

Data are mean±SD numbers of HCM‐related ambulatory visits, ED visits, inpatient admissions, mean LOS, and pharmacy use PPPM by demographic group during variable follow‐up.

ED indicates emergency department; HCM, hypertrophic cardiomyopathy; HCRU, health care resource use; LOS, length of stay; and PPPM, per‐patient‐per‐month.

^* P<0.05 using 2‐sample t tests for 2‐group comparisons or ANOVA for comparisons across ≥3 groups.

^† Data for other (n=77) and unknown/missing (n=2016) not reported here.

During the 1‐year follow‐up period, Black patients had fewer ambulatory visits than White, Asian, or Hispanic patients, and patients aged 18 to 39 experienced more ED visits than those in other age groups (Tables S17 and S18). Compared with patients from other geographic regions, patients in the Midwest had substantially more ED visits (Table S19). All between‐group comparisons were significant (P<0.001).

HCM‐Related Health Care Costs

Mean±SD ambulatory care costs per month were higher for male compared with female patients during variable follow‐up (366.6 [1040.8] USD versus 270.1 [899.1] USD) (Figure 3; Table S20). White and Black patients had greater total health care costs per month than Asian or Hispanic patients. Patients aged 18 to 39 had the highest mean ED visit cost per month compared with other age groups. Patients receiving Medicare had greater mean total costs±SD per month than patients with commercial insurance (2099.7 [7223.7] USD versus 1644.4 [4304.3] USD), and patients receiving Medicare had greater mean monthly inpatient admission costs than patients with commercial insurance (1637.0 [7015.7] USD versus 995.9 [3830.2] USD; Table S21). Patients in the Midwest had the greatest mean total health care costs per month (2071.2 [6420.1] USD), followed by patients in the South (1973.9 [5795.5] USD) and the West (1769.5 [5307.6] USD). The lowest mean total health care cost was seen in patients in the Northeast (1440.3 [3912.4] USD; Table S21). All between‐group comparisons were significant (P<0.05).

Figure 3. Mean HCM‐related health care costs by (A) sex, (B) race and ethnicity, (C) age, (D) payor, and (E) geographical region during variable follow‐up. USD, PPPM.^*,† .

*P<0.05 using 2‐sample t tests for 2‐group comparisons or ANOVA for comparisons across ≥3 groups. *The mean total monthly costs for each demographic group is shown at the top of each bar; ^†Data for patients with other payor (n=77) and unknown/missing payor (n=2016) are not reported here. ED indicates emergency department; HCM, hypertrophic cardiomyopathy; PPPM, per‐patient‐per‐month; and USD, US dollars.

Male patients experienced greater mean total health care costs than female patients during the 1‐year follow‐up period (26 350.7 USD versus 23 348.2 USD; Table S22). Compared with those receiving Medicare, patients with commercial insurance had greater mean ambulatory care costs (6562.2 USD versus 3844.4 USD) during the 1‐year follow‐up period (Table S23). All between‐group comparisons were significant (P<0.05).

DISCUSSION

In this retrospective real‐world database study of patients with oHCM, we demonstrate significant variation in MACE, HCRU, and health care costs by sociodemographic groups. First, we found that Black patients had the highest rate of MACE during variable follow‐up, whereas Asian patients had the lowest rate. Next, female patients experienced higher rates of stroke, HF, and all‐cause mortality than male patients over variable follow‐up. In addition, differences in rates of MACE across geographical regions were observed, with patients in the South and Midwest experiencing a higher rate of MACE than patients in the Northeast. Similarly, older patients and patients receiving Medicare or Medicaid had a higher rate of MACE than younger patients or patients with commercial insurance. Finally, differences in HCRU and health care costs were also observed across sociodemographic groups, with Black patients experiencing more inpatient admissions than those from other racial and ethnic groups, and White patients and Black patients had greater total health care costs than Asian or Hispanic patients during variable follow‐up.

Our observed rate of MACE among male and White patients is similar to that reported by a prior EHR‐based study of clinical outcomes among US patients with oHCM with data recorded in the IBM Explorys system between 2009 and 2019, which reported rates of 35.0%, 25.9%, and 1.3% for AF, HF, and cardiac arrest, respectively, over 12 months of follow‐up. ²⁰ Importantly, we highlight disparities in the rate of MACE between sociodemographic groups. Specifically, we demonstrate that Black patients had substantially higher rates of cardiovascular hospitalization than other racial or ethnic groups during variable follow‐up. These findings are similar to the adjacent disease state of HF, in which patient outcomes have also been shown to differ by race, with Black patients with HF experiencing higher rates of hospitalization than matched White patients. ²¹ Moreover, in our analysis, female patients experienced higher rates of cardiovascular hospitalization, HF, stroke, and all‐cause mortality than male patients across variable follow‐up, which is consistent with several previous studies finding that female patients with oHCM are at greater risk of HCM‐related complications than male patients, including HF and mortality. ²² , ²³ , ²⁴ , ²⁵ , ²⁶ These data highlight the need for further research to establish the causes of the observed differences in MACE incidence between men and women with oHCM.

Differences in medication use and receipt of therapeutic procedures between sociodemographic groups were also observed. Female patients had a higher rate of any prescribed medication, and a lower rate of any therapeutic procedure and implantable cardioverter‐defibrillator implantation than male patients during variable follow‐up. These data are consistent with a previous EHR‐based study of US‐based patients with oHCM with data recorded in the IBM MarketScan database between 2016 and 2018, which also found that women were less likely to receive implantable cardioverter‐defibrillator implantation than male patients. ²⁷ In this study Black patients had lower rates of any therapeutic procedure including SRT and implantable cardioverter‐defibrillator implantation than White patients across all follow‐up periods. These data are consistent with a previous analysis of patients with oHCM with data in the National Inpatient Survey from 2012 to 2018, which also found that Black patients were less likely to undergo SRT procedures than White patients. ²⁸

Substantial variation in HCRU was seen across sociodemographic groups. Younger patients had fewer inpatient admissions and shorter inpatient LOS than older groups but did have more frequent health care system contact in the form of ambulatory visits. Our findings align with a prior EHR‐based analysis reporting that over a 1‐year follow‐up period, 22.7% of patients with oHCM in the United States had an inpatient admission, and 99.1% had an outpatient visit. ⁶ Similarly, variation between types of health care costs was observed. Although White patients endured the highest total health care costs and ambulatory care costs, Black and Hispanic patients had greater ED costs. Mean HCM‐related health care costs during 1‐year follow‐up in this study for female, male, and White patients were comparable to the 26 929 USD mean 1‐year health care costs for oHCM reported by Jain et al. ⁶ In patients with HF non‐Hispanic White race and ethnicity has also been shown to be associated with greater out‐of‐pocket health expenditure, indicating greater overall health care spending than for patients of other racial and ethnic groups. ²⁹ Differences in spending between racial and ethnic groups could result from documented differences in access to health insurance and health services. ³⁰ The potential impacts of differences in sociodemographic characteristics on the clinical outcomes, HCRU, and health care costs of patients with oHCM may be important considerations in ensuring equitable access to novel diagnostic and therapeutic modalities. ³¹ , ³²

Limitations

The diagnoses, comorbidities, HCRU, and costs of patients with HCM were identified using diagnosis codes. However, this methodology is subject to inconsistencies. For instance, medical records may have been incorrectly coded, or codes may have been included as rule‐out criterion. Also, though diagnosis codes signify only disease presence, we required eligible patients to have at least 2 claims with diagnosis codes for HCM to reinforce diagnostic accuracy. Additionally, generic codes, such as codes for “other cardiomyopathy” and “unspecified cardiomyopathy,” were not included when identifying patients for the study. Health care costs were defined as the amount billed by the payer, which may not reflect what a patient paid for their health care, but the amount charged to a payor. Study data were limited to patients in the United States, so findings may not be generalizable to other countries. Study data were also limited to patients of White, Black, Asian, and Hispanic race and ethnicity and patients of American Indian/Native American and other racial and ethnic backgrounds were not included. Data were also limited to patients with a defined payor, and patients without health insurance or other coverage were not included. Hence, these results may not be applicable to patients without health insurance. Data validity may be limited by missing data; however, this limitation is inherent in all real‐world studies. As the objective of the present study was descriptive, all analyses are unadjusted. As the identification and claims periods in this study were from January 1, 2013, to December 31, 2021, this study did not capture the real‐world impact of commercially available cardiac myosin inhibitor therapies.

CONCLUSIONS

This study illustrates that among patients with oHCM, the rates of MACE, HCRU, and health care costs vary substantially between sociodemographic groups. Black patients incur greater inpatient and ED costs, and clinical and financial outcomes are significantly different across geographical regions and among patients receiving Medicaid and Medicare rather than commercial insurance. Further studies are warranted to clarify the causes of the observed variation between sociodemographic groups.

Sources of Funding

This study was funded by Cytokinetics Inc.

Disclosures

Nosheen Reza is supported by the National Heart, Lung, And Blood Institute of the National Institutes of Health under Award Number K23HL166961. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Nosheen Reza declares speaking honoraria from Zoll, Inc, research grants to her institution from Bristol Myers Squibb, Inc, consulting fees from Roche Diagnostics, American Regent, Bristol Myers Squibb, Inc, AstraZeneca, Idorsia, and Novo Nordisk. Michael Butzner and Sanatan Shreay are employees of, and hold stock in, Cytokinetics Inc. Kirti Batra, Qiana Amos, and Ami Buikema are employees of Optum Inc, which acted as a paid consultant to Cytokinetics Inc in connection with this study. Anjali Owens reports consulting for Bayer, Avidity, Alexion, Cytokinetics, MyoKardia/Bristol Myers Squibb, Lexeo, Imbria, Corvista, Tenaya Therapeutics, Stealth BioTherapeutics, Edgewise Therapeutics, and BioMarin Pharmaceuticals and research grant to the institution from Bristol Myers Squibb.

Supporting information

Tables S1–S23

Supplemental Methods

Figures S1–S3

STROBE Checklist