Abstract Body (Do not enter title and authors here):
Background:
Age-related differences in comorbidity burden and social determinants of health may influence outcomes in patients with hypertrophic cardiomyopathy (HCM), yet these relationships remain underexplored at a national level.

Methods:
We conducted a retrospective cross-sectional analysis using the National Inpatient Sample (NIS) from 2008–2023. Adult hospitalizations with a primary diagnosis of HCM were stratified into three age groups: <45, 45–64, and ≥65 years. We examined associations between age and clinical/socioeconomic factors, including Charlson and Elixhauser comorbidity indices, insurance type, and median household income quartile by ZIP code. Multivariable logistic regression was performed to assess predictors of in-hospital mortality.

Results:
Among an estimated 25,530 weighted hospitalizations for HCM, older adults (≥65 years) exhibited a significantly greater comorbidity burden, with 56% having a Charlson comorbidity index ≥3, compared to 35% in those <45 years. A higher proportion of older adults resided in lower-income ZIP codes (lowest quartile: 26% vs. 14%, p<0.001). Adjusted analysis identified both age ≥65 (aOR 3.74, 95% CI: 1.63–8.59, p=0.002) and malnutrition (aOR 2.01, 95% CI: 1.27–3.19, p=0.003) as independent predictors of in-hospital mortality.

Conclusion:
Advanced age and adverse socioeconomic conditions are associated with higher comorbidity burden and increased in-hospital mortality in patients hospitalized with HCM. These findings highlight the importance of integrating age- and equity-focused approaches in managing HCM.