Abstract
Aim
This study describes economic burden of obstructive hypertrophic cardiomyopathy (HCM) in France, with consideration of disease severity as measured by New York Heart Association (NYHA) class.
Methods and results
This observational, retrospective study used data from the French National Health Data System. Adults (≥18) with at least one disease related hospitalization during 2012–18 were included. Patients with <1-year follow-up or phenocopy disorders were excluded. Patients were stratified by disease severity class based on disease specific treatments and symptoms. Healthcare resources use, and costs were estimated per patient-year (PY). Annual cost before and after septal reduction therapies (SRT) was estimated. Overall, 6823 patients were identified (baseline NYHA class I–IV: 4%, 32%, 60%, and 4%, respectively). Mean (standard deviation) follow-up was 4.4 (2.5) years, comprising 30 228 PYs. Total burden was €388 million (€12 824 per PY), and higher NYHA class was associated with higher cost per patient year: €8881 and €22 818 for classes I and IV, respectively. Hospitalizations accounted for most costs (54%); 71% were cardiovascular-related hospitalizations, 46% disease-related. Mean cost per PY was lower 1 year before vs. after SRT, including the intervention (€13 726 vs. €18 565). Mean sick-leave-related costs per PY were €310, €673, €757, and €774 for classes I–IV, respectively.
Conclusion
Obstructive HCM has a high economic burden driven by cardiovascular hospitalizations. Higher disease severity yielded higher costs associated with medical care and sick leave than lower classes. Results support need for new therapies to improve both symptoms and disease severity.
Keywords: Cost of illness, Economic evaluation, Heart failure, Cohort studies, Obstructive hypertrophic cardiomyopathy, Cardiovascular diseases
Graphical Abstract
Graphical Abstract.
Key Learning Points.
What is already known?
Hypertrophic cardiomyopathy (HCM) has significant clinical burden, including increasing and disabling dyspnoea at rest, especially as the disease progresses.
What this study adds?
In France, the economic burden of obstructive HCM was high estimated at €12 824/PY, more than half of the healthcare costs incurred were due to hospitalizations (mainly cardiovascular-related hospitalizations).
Patients with obstructive HCM were admitted to hospital, on average, 2.5 times per annum.
Annual costs per patient with the highest disease severity (NYHA class IV) were nearly triple those with the lowest severity (NYHA class I).
Introduction
Hypertrophic cardiomyopathy (HCM) is the most common cardiovascular disorder characterized by left ventricular hypertrophy that is not solely explained by abnormal load charge.1,2 It is usually an inherited cardiovascular disorder1,2 but it can be acquired.3 HCM occurs as obstructive (about two-thirds of HCM patients) and non-obstructive sub-types.4,5
Advances in cardiac imaging, arrhythmia prophylaxis, genetic testing, cardiac surgery, interventional cardiology, and heart transplantation have improved the prognosis of patients with HCM. However, despite these advances, healthcare costs and morbidity remain significant.4 Studies have shown that if HCM is not well controlled, it is associated with an increased risk of downstream cardiovascular disease, symptoms, and impaired quality of life, resulting in a significant economic burden.6–12 A German study showed that HCM was the most resource-intensive disease among all chronic systolic heart failure diseases, with an associated cost of €4681/patient-year (PY); however, costs reported in the study were adjusted to 2009, and, as such, the burden is likely to be substantially higher today.12 Major cardiac interventions such as surgical septal reduction therapies (SRT) may be an option for patients who meet specific medical criteria. However, the risks associated with these procedures might be too high for some patients, or they might choose not to undergo this treatment. Surgical interventions lead to an increase of healthcare resource use (HCRU) and consequently substantial healthcare costs within the 12-months after interventions.13 These costs are mainly driven by inpatient stays in specialized units, surgical costs, and long-term rehabilitation.
Several recent studies examined the economic burden of each obstructive HCM subtype in the USA. Yet, there are very few longitudinal studies on the economic burden of obstructive HCM outside the USA.13–17
The French National Healthcare Data System (SNDS), a centralized national information resource for studying hospital and outpatient care consumption, was utilized for this study. The aims of the study were to estimate the economic burden of obstructive HCM in France as captured by HCRU data, from the perspective of the national health insurance (NHI), and with consideration of disease severity as measured by the New York Heart Association (NYHA) functional classification system.
Methods
Study design and data sources
This retrospective, longitudinal, observational study was performed using secondary pseudonymized data from the SNDS. This database contains demographic and HCRU data in the community (Données de Consommation Inter-Régimes), as well as in all public and private healthcare facilities [Programme de Médicalization des Systèmes d’Information (PMSI)].18 The SNDS covers more than 99% of the population living in France. Individuals with serious disease, costly disease, or long-term disease (LTD) are eligible for 100% reimbursement of related healthcare expenditure by the NHI.
Study periods
Inclusion period
Adult patients (≥18 years of age) with HCM were included between 1 January 2012 and 31 December 2018.
The index date was defined as 1 January 2012, or the first date of obstructive HCM diagnosis during the study inclusion period (2012–18) for patients with or without obstructive HCM information before the inclusion period, respectively.
Follow-up period
HCRU was continuously recorded between the index date and whichever occurred first of: 31 December 2019; death; or the date of last HCRU before an absence of healthcare consumption of at least 12 months (loss of follow-up).
Baseline period
For each patient, data were also collected 2 years before the index date to assess HCM medical history, comorbidities, and previous treatments. Data collection, therefore, could start as early as 1 January 2010, for patients with an index date of 1 January 2012.
Patient selection criteria
Patient inclusion criteria
All adult (≥18 years of age) patients with at least one hospital stay related to HCM [International Classification of Diseases 10th Revision (ICD-10) code I42.1, I42.2, or I42.9] were included. Patients with obstructive HCM were identified as those who had at least one hospital stay with ICD-10 code I42.1, or who had at least one ICD-10 code for HCM (I42.2 and/or I42.9) and at least one French Classification of Medical Procedures [Classification Commune des Actes Médicaux (CCAM)] code for SRT. All patients meeting the selection criteria were included. The selection process has already been detailed in a recent published study.19
SRT was identified with the CCAM codes DAFA006, DAFA007, and DDLF001.
Patient exclusion criteria
Patients with <1 year of follow-up in the PMSI were excluded. To ensure inclusion of patients with confirmed HCM, patients with the following phenocopy conditions were excluded: aortic stenosis (ICD-10 code: I06.0, I06.2, I35.0, or I35.2), hypertensive heart disease (I11.0 or I11.9), storage disease (E74, E75, E76, or Q87.1), or amyloidosis (E85.4 or E85.8).
Assessments
Demographic and medical data were assessed at the index date. Comorbidities (as defined in Supplementary material online, Table S1) were assessed during the baseline period of up to 2 years prior to the index date and the Charlson comorbidity index (CCI) was calculated.20 Clinical assessment of NYHA functional class is not available in the database used; therefore, a proxy was calculated using an algorithm based on treatments and symptoms that was developed in collaboration with expert cardiologists.19
During study follow-up, the collected measures of HCRU were those for drug treatments and non-pharmacological treatments, medical devices, community consultations, paramedic services (e.g. nurse and physiotherapist appointments), hospital consultations, hospitalizations, home hospitalizations, laboratory tests, medical procedures (including SRT), transportation (e.g. to and from hospital, or a medical or paramedic appointment), laboratory tests, sick leave and disability pensions, and other costs. Patients may have changed NYHA class over the study period. The HCRU measures directly correspond to those incurred when the patient was in a specific NYHA class.
Cost evaluation
HCRU and their related costs were determined using reimbursed fees available in the database, using the NHI (payer) perspective. Costs were expressed in 2022 euros/PY. All HCRU and costs were assessed for private and public hospitalizations, outpatient physician visits, transportation, medical procedures, laboratory tests, dispensing of pharmacies drugs, invalidities, etc. The SNDS includes all records of sick leave because patients are entitled to a daily allowance from NHI except for the first 3 days of sickness absence. Costs related to absenteeism from work (sick leave compensation revenue and disability pension) were restricted to patients 62 years of age or younger because it is the legal age to retire in France (retirees do not get sick leave and disability pensions).21 Costs were assessed over the study period and separately for 12 months before and after SRT for patients who underwent the procedure (the cost of the SRT procedure was included in the ‘after SRT’ cost assessment).
Statistical methods
Continuous data were summarized by their mean, standard deviation (SD), median, and first and third quartiles. Categorical data were summarized by percentage.
Given that all HCRU are reported in the database, no imputation of missing values was performed. Total HCRU related costs were computed by dividing total costs (sum of costs for all patients included from index date to the end of follow-up)/follow-up duration (sum of the duration of follow-up of all patients included in year). This aggregated indicator was computed for all patients and according to disease severity (NYHA class).
The statistical analyses were performed using SAS software (version 9.4).
Compliance with ethical standards
In accordance with the regulations in force, patient consent was not necessary because the study used pseudonymized, secondary data, there was a public interest in assessing (for the first time to our knowledge) the economic burden of obstructive HCM by NYHA in France, and the protection of patients’ rights and freedom was guaranteed. The study protocol obtained approval from the ethics and scientific committee for research, studies, and evaluations in the field of health (Comité Éthique et Scientifique pour les Recherches, les Études et les Évaluations dans le domaine de la Santé; File 1912776bis, on 8 October 2020). Authorization to use the data was granted by the French data protection authority (Commission Nationale de l’Informatique et des Libertés; Decision DR-2020-373 and authorization number 920414).
The STROBE cohort reporting guidelines were used.22
Results
Study population
Between 2012 and 2018, 6823 adult patients with obstructive HCM who had at least one HCM hospitalization were included (Figure 1), of whom 562 patients had undergone SRT.
Figure 1.
Study population selection. * Patients with aortic stenosis, hypertensive heart disease, storage disease, or amyloidosis. † Includes 2252 patients whose first diagnosis during the study period was non-obstructive HCM followed by a subsequent diagnosis of obstructive HCM. ‡ Includes 562 patients with a septal reduction therapy in the follow-up period. Abbreviations: HCM, hypertrophic cardiomyopathy; ICD-10, International Statistical Classification of Diseases and Related Health Problems 10th Revision; LTD, long-term disease.
Patients were followed-up for a mean (SD) of 4.4 (2.5) years, corresponding to 30 228 PYs in total.
Baseline patient characteristics
Mean (SD) age was 66.2 (16.7) years and 54.7% of patients were male (Table 1). The mean (SD) CCI was 3.8 (2.3) points. Patients at the index date were distributed among NYHA classes as follows: 294 (4.3%) in class I; 2150 (31.5%) in class II; 4102 (60.1%) in class III; and 277 (4.1%) in class IV.
Table 1.
Baseline patient characteristics
| NYHA class at index date | |||||
|---|---|---|---|---|---|
| Variable | Total | I | II | III | IV |
| Patients, N (%) | 6823 | 294 (4.31) | 2150 (31.51) | 4102 (60.12) | 277 (4.06) |
| Follow-up duration, years | 30 228 | 857 | 11 104 | 17 484 | 783 |
| Male, N (%) | 3730 (54.67) | 173 (58.84) | 1301 (60.51) | 2097 (51.12) | 159 (57.40) |
| Age, years, mean (SD) | 66.24 (16.66) | 56.91 (21.83) | 59.63 (16.81) | 70.30 (14.74) | 67.23 (15.76) |
| CCI, points, mean (SD) | 3.84 (2.32) | 2.67 (2.39) | 2.76 (2.12) | 4.45 (2.19) | 4.55 (2.08) |
| Comorbidities,a N (%) | |||||
| Atrial fibrillation/flutter | 1876 (27.50) | 17 (5.78) | 278 (12.93) | 1478 (36.03) | 103 (37.18) |
| Cardiac dysrhythmias | 2292 (33.59) | 29 (9.86) | 445 (20.70) | 1693 (41.27) | 125 (45.13) |
| Conduction disorders | 593 (8.69) | 10 (3.40) | 138 (6.42) | 403 (9.82) | 42 (15.16) |
| Coronary artery disease | 1169 (17.13) | 21 (7.14) | 322 (14.98) | 754 (18.38) | 72 (25.99) |
| Depression | 1091 (15.99) | 38 (12.93) | 322 (14.98) | 69 (16.92) | 37 (13.36) |
| Diabetes (T1DM and T2DM) | 1304 (19.11) | 28 (9.52) | 289 (13.44) | 913 (22.26) | 74 (26.71) |
| Heart failure | 1674 (24.53) | 14 (4.76) | 204 (9.49) | 1281 (31.23) | 175 (63.18) |
| Hyperlipidaemia | 1327 (19.45) | 22 (7.48) | 385 (17.91) | 862 (21.01) | 58 (20.94) |
| Hypertension | 5869 (86.02) | 63 (21.43) | 1739 (80.88) | 3800 (92.64) | 267 (96.39) |
| Hypercholesterolemia | 614 (9.00) | 11 (3.74) | 160 (7.44) | 411 (10.02) | 32 (11.55) |
| Previous events, N (%) | |||||
| Cardiac arrest | 45 (0.66) | 0 (0.00) | 16 (0.74) | 25 (0.61) | 4 (1.44) |
| DVT/PE | 123 (1.80) | 5 (1.70) | 34 (1.58) | 78 (1.90) | 6 (2.17) |
| Myocardial infarction | 170 (2.49) | 6 (2.04) | 47 (2.19) | 108 (2.63) | 9 (3.25) |
| Pacemaker—defibrillator | 337 (4.94) | 4 (1.36) | 79 (3.67) | 238 (5.80) | 16 (5.78) |
| Stroke/TIA | 417 (6.11) | 14 (4.76) | 113 (5.26) | 277 (6.75) | 13 (4.69) |
| Septal reduction therapy | 18 (0.26) | 1 (0.34) | 6 (0.28) | 10 (0.24) | 1 (0.36) |
CCI, Charlson comorbidity index; DVT, deep vein thrombosis; NYHA, New York Heart Association; PE, pulmonary embolism; SD, standard deviation; T1DM, type 1 diabetes mellitus; T2DM, type 2 diabetes mellitus; TIA, transient ischemic attack.
aComorbidities were identified within 2 years before the inclusion date.
In the 2 years prior to the index date, the most common comorbidities captured were hypertension (86.0%), cardiac dysrhythmias (33.6%), atrial fibrillation/flutter (27.5%), and heart failure (24.5%). In general, patients in higher NYHA classes had a greater comorbidity burden. The proportions of patients with a cardiac dysrhythmia, atrial fibrillation/flutter, and heart failure, respectively, were 9.9%, 5.8%, and 4.8% in the NYHA class I group and 45.1%, 37.2%, and 63.2% in the NYHA class IV group.
HCRU of patients with obstructive HCM and corresponding costs
For patients with obstructive HCM, the mean number of hospital admissions was 2.52 per year (Table 2). They had a mean of 10.76 community consultations (general practitioners, cardiologists, and other specialist office visits, encompassing all non-hospital consultations) per year, with an additional 3.44 outpatient hospital consultations. Per year, they also underwent, on average, 104.52 paramedic acts (a paramedic may perform multiple acts during a single visit), 7.06 medical procedures, and 14.72 laboratory visits [including, for example, B-type natriuretic peptide (BNP)/NT-proBNP, thyroid-stimulating hormone, and urine analysis]. Per year, they were compensated for 13.94 days of sick leave or disability pension on average.
Table 2.
Overall healthcare resource use and cost of healthcare resource for obstructive HCM, by NYHA class, per patient
| Total (n = 6823) |
NYHA class Ia (n = 409) |
NYHA class IIa (n = 3592) |
NYHA class IIIa (n = 5353) |
NYHA class IVa (n = 587) |
||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Resource | HCRU (n/PY) |
Cost (€/PY) | HCRU (n/PY) |
Cost (€/PY) | HCRU (n/PY) |
Cost (€/PY) | HCRU (n/PY) |
Cost (€/PY) | HCRU (n/PY) |
Cost (€/PY) |
| Drugs (prescription fills) | 20.21 | 1495 | 10.32 | 949 | 16.34 | 1192 | 22.93 | 1673 | 25.02 | 2446 |
| Medical devices | 9.05 | 645 | 5.86 | 517 | 6.42 | 402 | 10.72 | 791 | 12.51 | 961 |
| Community consultations | 10.76 | 303 | 6.86 | 172 | 9.29 | 250 | 11.81 | 340 | 12.37 | 362 |
| Paramedic services (acts)b | 104.52 | 1091 | 50.50 | 554 | 53.23 | 597 | 138.92 | 1423 | 122.85 | 1255 |
| Hospital consultations | 3.44 | 283 | 2.61 | 193 | 3.17 | 264 | 3.59 | 294 | 4.82 | 424 |
| Hospitalizations (admissions) | 2.52 | 6944 | 1.62 | 4782 | 1.92 | 5011 | 2.91 | 7929 | 3.37 | 14 746 |
| Cardiovascular-related | 1.05 | 4883 | 0.69 | 3097 | 0.74 | 3290 | 1.21 | 5629 | 2.28 | 12 764 |
| HCM-related | 0.64 | 3200 | 0.54 | 2319 | 0.51 | 2475 | 0.71 | 3534 | 1.14 | 6984 |
| Non-cardiovascular related | 1.47 | 2061 | 0.93 | 1685 | 1.18 | 1721 | 1.70 | 2299 | 1.09 | 1982 |
| Home hospitalizations (admissions) | 0.02 | 63 | 0.03 | 299 | 0.02 | 44 | 0.01 | 65 | 0.02 | 24 |
| Laboratory tests | 14.72 | 229 | 5.82 | 104 | 9.45 | 153 | 18.13 | 277 | 22.94 | 363 |
| Medical procedures | 7.06 | 381 | 5.12 | 240 | 6.94 | 365 | 7.22 | 396 | 7.25 | 420 |
| Transportation | – | 741 | – | 482 | – | 597 | – | 835 | – | 962 |
| Sick leave or disability pension, days | ||||||||||
| All patients | 13.94 | 332 | 11.32 | 284 | 17.47 | 418 | 11.07 | 270 | 30.99 | 541 |
| Patients ≤62 years oldc | 30.70 | 736 | 13.88 | 310 | 27.13 | 673 | 30.73 | 757 | 46.74 | 774 |
| Other | 3.21 | 318 | 3.22 | 305 | 2.64 | 243 | 3.51 | 366 | 4.42 | 316 |
| Total | – | 12 824 | – | 8881 | – | 9535 | – | 14 658 | – | 22 818 |
HCM, hypertrophic cardiomyopathy; HCRU, healthcare resource use; NYHA, New York Heart Association; PY, patient-year.
aPatients may change NYHA class over the study period. HCRU corresponds to that incurred over the period the patient belonged to a specific NYHA class.
bParamedics acts: nurses and physiotherapists may perform several acts during a single consultation.
cThe patient’s age was examined at the time the patient entered the NYHA class. 62 years as a threshold was utilized to reflect a patient proportion at typical retirement age.
Total HCRU costs were €12 824/PY and amounted to a total burden of €387 632 869 (across 30 228 PYs) for the obstructive HCM population in the study.
About three-quarters of the HCRU costs were attributed to three items: all-cause hospitalizations (admissions; €6944/PY, 54.2% of costs), drugs (prescription fills; €1495/PY, 11.7% of costs), and paramedic acts (€1091/PY, 8.5% of costs) (Figure 2). Costs of cardiovascular-related hospitalizations overall, and HCM-related hospitalizations, were €4883/PY and €3200/PY, respectively; costs of non-cardiovascular-related hospitalizations were €2061/PY.
Figure 2.
Distribution of itemized annual HCRU costs for obstructive HCM. Abbreviations: CV, cardiovascular; HCM, hypertrophic cardiomyopathy; HCRU, healthcare resource use.
There was a positive association between increasing NYHA class and increasing resource use (Table 2 and Figure 3). For example, patients in NYHA class IV were admitted to hospital, on average, 3.37 times per year compared with 1.92 and 2.91 admissions per year for patients in NYHA class II and class III, respectively, and more than double the admission rate for patients in NYHA class I (with 1.62 admissions per year). Furthermore, the number of days compensated for sick leave and disability per year was, on average, approximately three-times more for a patient in NYHA class IV than that for a patient in NYHA class I, with 30.99 and 11.32 days per year, respectively. For patients 62 years of age or younger at index date (defined to reflect a predominant retired population), the costs related to sick leaves were €310/PY, €674/PY, €757/PY, and €774/PY for NYHA classes I, II, III, and IV, respectively.
Figure 3.
Distribution of HCRU costs per patient year with obstructive HCM. Sick leave and disability pension are for all patients, regardless of their age. Abbreviations: HCM, hypertrophic cardiomyopathy; HCRU, healthcare resource use; PY, patient-year.
Increasing NYHA class was associated with increasing economic burden associated with obstructive HCM, with an approximately three-fold increase between NYHA class I and NYHA class IV (€8881/PY and €22 818/PY, respectively).
HCRU costs per PY varied by geographical location and were highest in Southeastern and Northeastern France, and in French overseas departments and territories (Figure 4A). Costs ranged from €9245/PY in Cantal (Central France) to €33 231/PY in Mayotte (territory in the Indian Ocean). The number of patients hospitalized per geographical location followed approximately the same repartition than costs (Figure 4B).
Figure 4.
(A) Annual HCRU cost per patient with hospitalized obstructive HCM, by geographical area. (B) Annual number of patients hospitalized for obstructive HCM, by geographical area. Abbreviations: HCM, hypertrophic cardiomyopathy; HCRU, healthcare resource use.
There were 637 instances of SRT among 562 patients; 494 were alcohol septal ablations and 147 were septal myectomies. HCRU costs were higher during the year after SRT (including the procedure itself) than during the year before SRT (€18 565/PY vs. €13 726/PY; Table 3).
Table 3.
Healthcare resource costs in the year before and the year after SRT (N = 562)
| Resource | Healthcare costs in the 12 months before SRT (€/PY) | Healthcare costs in the 12 months after SRT (€/PY)a |
|---|---|---|
| Hospitalizations (including for SRT) | 9213 | 13 878 |
| Drugs | 1048 | 936 |
| Paramedic services | 319 | 370 |
| Medical devices | 380 | 408 |
| Transportation | 507 | 501 |
| Sick leave or disability pension | 632 | 687 |
| Hospital consultations | 412 | 334 |
| Medical procedures | 607 | 750 |
| Laboratory tests | 211 | 200 |
| Community consultations | 316 | 301 |
| Home hospitalizations | – | 2 |
| Other | 82 | 199 |
| Total | 13 726 | 18 565 |
PY, patient-year; SRT, septal reduction therapy.
aThe 12-months period after SRT commenced on the day the SRT procedure was coded and as such included costs associated with the procedure.
Discussion
Our study is one of the few studies to have analysed the economic burden of obstructive HCM at a national level outside of the USA and, more generally, with consideration of disease severity as measured by NYHA class.
With this national observational study, we show that the economic burden of obstructive HCM in France was substantial (€12 824/PY) and that the burden nearly tripled between NYHA class I and IV groups. Hospitalizations, mainly cardiovascular hospitalizations related to obstructive HCM, accounted for more than half of the costs. In addition to the direct financial costs, this study was also able to examine the impact of sick leave and disability pensions, which have not been included in previous economic burden studies. Sick leave and disability pensions accounted for 3% of all annual health costs, with patients in NYHA class IV being affected for nearly three-times longer than those in NYHA class I. In a real-world HCM US study, symptomatic obstructive HCM-related HCRU costs were around US$35 00014 (i.e. twice as much as the cost of the all-cause HCRU for obstructive HCM in our study). In another US study based on claims data, the all-cause HCRU costs for obstructive HCM were US$53 000/PY.15 Consistent with our findings, a third US study also found increasing costs for patients undergoing SRT, driven by inpatient hospitalizations and surgical costs.12 A study using nationally representative administrative claims data conducted in Germany in 1141 adult patients with obstructive HCM, during the period 2012–2018, reported that these patients were admitted to hospital, on average, 0.7 times per year (0.1 times per year for HCM) and the average cost per patient (total outpatient, inpatient, and pharmacy costs) was €5754 per year.23 An observational cohort study, based on the clinical practice research datalink between 2009 and 2020 in the UK, highlighted that the health economic burden of obstructive HCM is considerable and increases with severe disease.24
It appears that the HCRU and associated costs, including sick leave and disability pensions, are substantial in obstructive HCM. Our study reports the major impact of increasing disease severity on HCRU, and the corresponding economic burden associated with obstructive HCM. Therefore, it is crucial that therapeutic management of the disease is improved at an early stage. Slowing disease progression to higher severity levels could prevent cardiovascular complications and hospitalizations. Ideally, new treatments for symptomatic disease will stabilize or reduce the economic and clinical burden to patients and the healthcare system.15 Being able to demonstrate a reduction in cardiovascular hospital admissions and complications associated with a new treatment will be particularly important to assess in future clinical trials for obstructive HCM. However, France has unique healthcare insurance, which covers most medical costs in a regulated healthcare system. Therefore, results cannot be easily compared with those of studies from other countries. For example, in the real-world US studies assessing HCRU-related costs, patients included were only commercially insured patients with at least 12 months of health insurance coverage leading to a selection bias. Thus, these findings may not be generalizable to other populations (e.g. patients with fee-for-service or who are uninsured).14,15 The same limit must be acknowledged for the UK study as only patients within the CPRD dataset who were registered with general practices and agreed to a linkage process were included.24 Results from the German study were based on a representative sample of the German population but costs included in the analyses were different and the analyses included both symptomatic and asymptomatic patients by contrast with our analyses including only patients who have experienced a hospitalization related to HCM.23
This study also led us to analyse the geographical distribution of healthcare resource costs. The granularity of the results of this study highlights a significant disparity in the per patient cost of obstructive HCM in the different French regions. This is probably owing to several factors, such as the organization of care in the different regions, medical desertification in certain areas and access to healthcare resources, the presence or absence of an expert centre for the management of cardiomyopathies, genetic heterogeneity, comorbidities, the lack of recognition and screening for the disease, or low number of patients in some areas. Even in a country where patient care is well organized through a dynamic network of cardiomyopathy centres of expertise and referral, recommendations and harmonized management need to be developed. Before now, France had a national-level large protocol for diagnosis and the dissemination of expert advice. However, the publication of European Society of Cardiology recommendations for the management of cardiomyopathies in August 2023 is expected to help to improve disease recognition, training for cardiologists, and care pathways.25
Strengths and limitations
This study had multiple strengths. It was based on real-world data and involved national coverage. It encompassed all HCRU and, unlike other HCM economic studies, assessed sick leave and disability pension expenditures. The large study population allowed for the examination of HCRU and costs by NYHA class. Previous studies of outcomes by NYHA class assessed based on baseline NYHA class26–28; whereas our study was able to attribute HCRU and costs to the specific NYHA class the patient was in when the cost occurred, leading to a more accurate assessment of economic burden by NYHA class.
This study was subject to several limitations, some of which commonly pertain to claims database analyses. Because results of diagnostic tests were not available in the database, we relied on diagnoses in claims to identify patients with obstructive HCM. In addition, NYHA class and symptoms are not routinely directly coded in the database and patients were assigned to NYHA classes based on an algorithm developed with clinical expert input, and, as such, there may be inaccuracies in class assignment. The quality of claims data used for this study depended on the individual completeness and quality of coding for billing purposes and on the existing classification systems. Because diagnosis coding for HCM was only available in inpatient claims data, only patients that have experienced a hospitalization in which HCM was coded were included. Therefore, patients with less severe disease were likely under-represented. Consequently, overall costs of HCM could not be assessed globally and inpatients costs may be over-represented in our study population. Thus, the large proportion of the total cost of obstructive HCM that was accounted for by hospital admission costs is partially due to the patient selection process, which was partly based on ICD-10 codes in hospital discharges. Health conditions were identified through specific algorithms developed by the NHI or in conjunction with several expert cardiologists. These algorithms were based on specific ICD-10 codes from hospitalizations and/or LTD. Thus, patients not hospitalized for these specific conditions or without LTD were not identified, leading to a potential underestimation of these conditions. Additionally, only patients with at least 1 year of follow-up (and thus still alive at 1 year) in the PMSI were included in this study because patients were required to have at least 1 year of follow-up data available. Thus, patients that did not survive for a year following hospitalization were not included in the study. Lastly, as we used the perspective of NHI, the amounts collected for the costs of sick leaves and invalidities only correspond to the portion reimbursed by it. The overall valuation of these days of lost productivity is therefore underestimated and could be better estimated from a broader economic perspective, using the human per capita method or the friction cost method.
Conclusion
This study showed that, despite current available therapeutics, including invasive SRT, HCRU for and the economic burden of obstructive HCM is considerable. More effective therapeutic management is, therefore, needed to curtail them. The observed geographical disparities in healthcare resource costs should be further examined.
Supplemental material
Supplementary material is available at European Heart Journal – Quality of Care and Clinical Outcomes online.
Supplementary Material
Acknowledgements
The authors gratefully acknowledge the contributions of Eléonore Herquelot (ORCID 0000-0003-3003-8459) for the statistical analyses. Eléonore is an employee of Heva (Lyon, France), which conducted the study on behalf of Bristol Myers Squibb. The authors thank the ‘Direction de la stratégie, des études et des statistiques’ (DSES), ‘Département Accès, Traitement et Analyse de la Donnée’ (DATAD) and ‘Demandes Externes (DEMEX) teams at the Caisse nationale de l’assurance maladie des Travailleurs Salariés’ (CNAMTS) for the data extraction. Writing and editorial assistance were provided by Joannie Tieulent and Cécile Conte, PhD, of Agency Heva, funded by Bristol Myers Squibb.
Contributor Information
Philippe Charron, AP-HP, IHU-ICAN, INSERM 1166, Sorbonne Université, Hôpital Pitié-Salpêtrière, 47 boulevard de l’hôpital, Paris 75013, France.
Carla Zema, Bristol Myers Squibb, Princeton, NJ 08648.
François-Emery Cotté, Bristol Myers Squibb, HEOR, Rueil–Malmaison 92500, France.
Arthur Juban, Bristol Myers Squibb, HEOR, Rueil–Malmaison 92500, France.
Aurélie Schmidt, Heva, Pharmaco-epidemiology, Lyon 69006, France.
Taryn Krause, Bristol Myers Squibb, Global HEOR Cardiovascular, Uxbridge, UK.
Michael Hurst, Bristol Myers Squibb, Global HEOR Cardiovascular, Uxbridge, UK.
Julia Gonzalez, Heva, Pharmaco-epidemiology, Lyon 69006, France.
Jean-Noël Trochu, CNRS, INSERM, Institut du Thorax, Centre Hospitalo-Universitaire Nantes, Nantes Université, Nantes 44007, France.
Author contributions
Philippe Charron (Conceptualization, Interpretation, Editing, Validation), Carla Zema (Conceptualization, Project administration, Validation), François-Emery Cotté (Conceptualization, Supervision, Validation), Arthur Juban (Conceptualization, Supervision, Validation), Aurélie Schmidt (Methodology, Data curation, Formal analysis, Validation), Taryn Krause (Conceptualization, Validation), Michael Hurst (Conceptualization, Supervision interpretation, Editing, Validation), Julia Gonzalez (Methodology, Data curation, Formal analysis, Validation), and Jean-Noël Trochu (Conceptualization, Interpretation, Editing, Validation).
Funding
This study was funded by Bristol Myers Squibb.
Consent: In accordance with the regulations in force, patient consent was not necessary because the study used pseudonymized, secondary data, there was a public interest in assessing (for the first time to our knowledge) the economic burden of obstructive HCM by NYHA in France, and the protection of patients’ rights and freedom was guaranteed.
Data availability
The data supporting the study findings are part of the National health data system (Système national des Données de Santé) and are available from the Health Data Hub (https://www.health-data-hub.fr/). Restrictions apply to the availability of these data containing potentially identifying and sensitive patient information. Special permission to access these data for this study was granted by the Ethics and scientific committee for health research, studies, and evaluations (Comité Ethique et Scientifique pour les Recherches, les Etudes et les Evaluations dans le domaine de la Santé; formerly CEREES) and the French data protection authority (Comité National de l’Informatique et des Libertés).
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
The data supporting the study findings are part of the National health data system (Système national des Données de Santé) and are available from the Health Data Hub (https://www.health-data-hub.fr/). Restrictions apply to the availability of these data containing potentially identifying and sensitive patient information. Special permission to access these data for this study was granted by the Ethics and scientific committee for health research, studies, and evaluations (Comité Ethique et Scientifique pour les Recherches, les Etudes et les Evaluations dans le domaine de la Santé; formerly CEREES) and the French data protection authority (Comité National de l’Informatique et des Libertés).