A new study suggests the introduction of personalized thresholds for diagnosing hypertrophic cardiomyopathy (HCM) in proposals that challenge long-standing one-size-fits-all diagnostic standards. Writing in the Journal of the American College of Cardiology, researchers state a case for tailoring diagnostic criteria based on age, sex and body size as part of a review of current approaches to improve accuracy and equity in identifying this cardiac condition. “Age, sex and body size influence the normal heart maximum wall thickness (MWT).” concluded the paper’s authors. Using a fixed LVH threshold ≥15 mm biases left ventricular hypertrophy (LVH) ascertainment in both population and HCM cohorts. A demographic-adjusted approach for LVH improves ascertainment and diagnostic accuracy.” Traditional threshold use Led by Hunain Shiwani, MD, from the University College London in the UK, the research team used the traditional ≥15-mm threshold to classify 4.3% (n=1,854) of the Population Cohort as hypertrophic with a significant sex skew (89% male) observed. Demographic-adjusted LVH thresholds (range: 10-17 mm) reduced ascertainment to 2.2% (n=945), reducing the sex skew (56% male). The research team also noted similar reductions in bias with height, weight and age. Further findings revealed the HCM cohort had a 2:1 male-to-female ratio with a significant proportion of patients (27% female and 18% male) receiving diagnoses of HCM despite having MWT below the traditional LVH threshold (<15 mm). Using demographic-adjusted LVH thresholds reduced these proportions to 7% of female individuals and 15% of male individuals (P < 0.0001). Female patients had lower absolute MWT (18 mm vs 19 mm; P < 0.001) but higher MWT z-scores (5.1 vs 4.5; P=0.05). Significant variation “MWT was modelled in healthy subjects, accounting for the complex, nonlinear relationships between age, sex, BSA and their collective impact on MWT,” the paper’s authors concluded. In healthy individuals, these demographic variables accounted for 36% of the variations observed in MWT measurements.” Commenting on the study’s implications and recommendations for a more personalized approach, the authors stressed its need owing to the current limitations of fixed thresholds. This included the failure to account for the influence of age, sex, and body size on normal heart dimensions that could lead to potential biases. These demographic factors posed an additional challenge in that they collectively could explain "approximately 36% of the variation in MWT" among healthy individuals, showing the need for more nuanced diagnostic criteria. Commenting on the need to reduce bias with the use of demographic-adjusted thresholds, the authors highlighted its demonstrated improvements in gender equity and accuracy. Sex-specific findings The authors went onto discuss the implications of their sex-specific findings, highlighting that women with HCM often presented at later stages of the disease with more severe symptoms despite having lower absolute MWT values. According to the team, this highlighted a diagnostic gap, as the fixed threshold "systematically precluded" diagnosis for certain female patients who could otherwise be identified using the adjusted criteria. In discussing the potential for improved outcomes using the personalised approach the paper reiterated that by integrating demographic adjustments into HCM diagnostic criteria, "early detection and risk stratification" could improve, especially for women and other underrepresented groups. Study methodology Left ventricular MWT was measured in 3 cohorts: a Reference Cohort of healthy adults (n=5,067 with no comorbidities with an age range of 59.9±10.3 years of which 2,462 [48.6%] were male), a Population Cohort (n=43,239, with comorbidities with an age range of 64.1±7.7 years of which 20,860 [48.2%] were male). The last cohort was an HCM Cohort (n=2,424) with an age range of 56.4±14.6 years of which 1,573 (64.9%) were male. Measurement used cardiovascular magnetic resonance (CMR) and a validated artificial intelligence algorithm. The Reference Cohort was used to developed demographically adjusted LVH thresholds, and individualized z-scores based on age, sex, and body surface area (BSA), which were used to explore the other cohorts. Sources: Shiwani H. Demographic-Based Personalized Left Ventricular Hypertrophy Thresholds for Hypertrophic Cardiomyopathy Diagnosis. J Am Coll Cardiol. 2024 Jan 13. [Article in Press]. Image credit: ibreakstock – stock.adobe.com