Impact of age on outcomes in patients with hypertrophic cardiomyopathy: a nationwide inpatient database study

Abstract

Abstract Background Hypertrophic cardiomyopathy (HCM) is an inherited cardiovascular condition, associated with increased risk of premature adverse events. Once considered a disease of the young, it is increasingly being recognized in septuagenarians and octogenarians, with a few small-scale studies indicating that the risk of adverse cardiovascular outcomes may be lower in the older population. Purpose There are limited data regarding the outcomes of elderly patients with HCM. We therefore investigated a nationwide cohort in the United States to evaluate the pattern of disease presentation and outcomes of HCM patients, with a focus on the geriatric population. Methods The Nationwide Inpatient Sample (NIS) was queried to identify patients who were admitted for any cause with a concomitant diagnosis of HCM between 2011 and 2014 using ICD-9 (International Classification of Diseases-9th Edition-Clinical Modification) diagnosis code 425.1. All patients were further sub-categorized based on their age into those less than 65 years of age (representative of younger population), 66–75 years, 76–85 years and more than or equal to 86 years. We performed the Chi-squared tests for categorical variables and Mann–Whitney U tests for continuous variables. Multiple logistic regression was performed to assess the predictors of mortality. A two-tailed p-value of <0.05 was considered to be significant. Results We identified 120,805 patients who were admitted with a diagnosis of HCM, of whom 46.4% were in the <65 age group, 21.5% were in the 66–75 age group, 20.5% were in the 76–85 age group, and 11.5% were in the >86 age group. The proportion of patients with ventricular fibrillation was lower (1.8% vs 1.0% vs 0.5% vs 0.1%, p<0.01), whereas the proportion of patients undergoing permanent pacemaker placement was higher (1.2% vs 2.3% vs 3.7% vs 3.6%, p<0.01) in successive age groups. The proportion of people undergoing operative procedures including septal myectomy (SM) (5.4% vs 4.5% vs 1.8% vs 0.2%, p-intervention <0.01) and alcohol septal ablation (ASA) (3.2% vs 3.3% vs 1.9% vs 1.0%, p-intervention <0.01) were lower in the advanced age groups when compared to the younger age groups. Pacemaker implantation (odds ratio (OR): 0.32, 95% confidence intervals (CIs): 0.20–0.50, p<0.01) and implantable cardioverter defibrillator (ICD) placement (OR: 0.059, 95% CI: 0.024–0.144, p<0.01) were found to be associated with decreased odds of in-hospital mortality across all age groups. Conclusion In a large nationwide cohort of HCM patients in the United States, a significant proportion of patients were septuagenarians and octogenarians. Fewer elderly patients with HCM underwent septal myectomy and alcohol septal ablation, while elderly patients underwent more pacemaker implants. A combination of reduced ventricular conduction abnormalities coupled with increased pacemaker implantation may be contributing to increased longevity in older HCM patients. Odds-ratio for predictors of mortality Funding Acknowledgement Type of funding source: None