January 3, 2024Open Access
Clinical to Population Prevalence of Hypertrophic Cardiomyopathy Phenotype: Insights From the National Echo Database Australia
Key Result
Routine echocardiography identified a hypertrophic cardiomyopathy phenotype prevalence of 2.96% in men and 1.70% in women, estimating 17.5 male and 8.2 female cases per 10,000 Australian adults.
Study Design
Type
Observational (n=650,700)
Multicenter
Yes
Structured PICO
P
Population
650,700 adult men and women undergoing routine echocardiography in Australia, assessed for the presence of hypertrophic cardiomyopathy phenotype.
O
Outcome
Prevalence of hypertrophic cardiomyopathy (HCM) phenotype, defined as end-diastolic wall thickness ≥15 mm anywhere in the left ventricle in the absence of another known cause of hypertrophy.
This large national echocardiographic registry study demonstrates that the hypertrophic cardiomyopathy phenotype is relatively common, affecting an estimated 17.5 per 10,000 men and 8.2 per 10,000 women in Australia.
Limitations
- Lack of clinical granularity to exclude other causes of ventricular hypertrophy such as hypertension, aortic stenosis, or cardiac amyloidosis.
- Does not capture socio-economic profiles or genetic testing results.
- Potential referral bias as individuals undergoing echocardiography are typically referred for known or suspected cardiac disease.
- Apical wall thickness is not routinely measured, potentially missing some hypertrophic cardiomyopathy cases.
- Limitations of pulsed-wave Doppler in accurately measuring high velocities across the left ventricular outflow tract.
Abstract
BackgroundThere is a paucity of data describing the underlying prevalence of hypertrophic cardiomyopathy (HCM), a primary genetic disorder characterised by progressive left ventricular (LV) hypertrophy and sudden death, from both a clinical and a population perspective.MethodsWe screened the echocardiographic reports of 155,668 men and 147,880 women within the multicentre National Echo Database Australia (NEDA) (2001–2019). End-diastolic wall thickness ≥15 mm anywhere in the left ventricle was identified as a characteristic of an HCM phenotype according to current guideline recommendations. Applying a septal-to-posterior wall thickness ratio >1.3 and LV outflow tract obstruction ≥30 mmHg (when documented), we further identified asymmetric septal hypertrophy and obstructive HCM (oHCM), respectively. The observed pattern of phenotypical HCM within the overall NEDA cohort (>650,000 cases) was then extrapolated to the ∼539,000 (5.7% of adult population) and ∼474,000 (4.8%) Australian men and women, respectively, who were investigated with echocardiography in 2021 on an age-specific basis.ResultsOverall, 15,380 cases (mean age 71.1±14.6 years, 10,138 men 65.9%) with the characteristic HCM phenotype within the NEDA cohort were identified. Of these 15,380 cases, 5,552 (36.1%) had asymmetric septal hypertrophy, and 2,276 of the 10,290 cases with LV outflow tract obstruction profiling data (22.1%) had obstructive HCM. A further 3,389 of 13,715 cases (24.7%) had evidence of LV systolic dysfunction (LV ejection fraction 1.3 and LV outflow tract obstruction ≥30 mmHg (when documented), we further identified asymmetric septal hypertrophy and obstructive HCM (oHCM), respectively. The observed pattern of phenotypical HCM within the overall NEDA cohort (>650,000 cases) was then extrapolated to the ∼539,000 (5.7% of adult population) and ∼474,000 (4.8%) Australian men and women, respectively, who were investigated with echocardiography in 2021 on an age-specific basis. Overall, 15,380 cases (mean age 71.1±14.6 years, 10,138 men 65.9%) with the characteristic HCM phenotype within the NEDA cohort were identified. Of these 15,380 cases, 5,552 (36.1%) had asymmetric septal hypertrophy, and 2,276 of the 10,290 cases with LV outflow tract obstruction profiling data (22.1%) had obstructive HCM. A further 3,389 of 13,715 cases (24.7%) had evidence of LV systolic dysfunction (LV ejection fraction <55%). Within the entire NEDA cohort (including those without LV profiling), HCM was found in 10,138 of 342,161 men (2.96%; 95% confidence interval CI 2.91%–3.02%) and 5,242 of 308,539 women (1.70%; 95% CI 1.65%–1.75%). When extrapolated to the Australian population, we estimate that a minimum of 15,971 men and 8,057 women presented with echocardiographic features of phenotypical HCM in 2021. This translates into a minimum caseload/prevalence of ∼17 adult men (∼2.5 in those aged ≤50 years) and eight adult women (∼1 in those aged ≤50 years) per 10,000 population meeting phenotypical HCM criteria. Using contemporary Australian echocardiographic and population data, we estimate that a minimum of 15,971 (17.5 cases/10,000) men and 8,057 women (8.2 cases/10,000) had echocardiographic evidence of phenotypical HCM in 2021. These disease burden data are particularly relevant as new treatment options are emerging.