Investigating Regional Differences in Cardiovascular Outcomes Among Patients Diagnosed with Hypertrophic Cardiomyopathy

OBJECTIVES: Studies examining the associations between geographic region and cardiovascular (CV) outcomes in patients with hypertrophic cardiomyopathy (HCM) were limited in size. We evaluated these associations in a large, national cohort of patients with HCM.

METHODS: Retrospective cohort study of adults diagnosed with HCM in Optum’s medical/ pharmacy claims and electronic health record data (January 2013 to December 2021). We report incidence rates of CV outcomes (atrial fibrillation [AF], stroke, heart failure [HF], ventricular tachycardia [VT], and ventricular fibrillation [VF] from first HCM diagnosis until death, health plan disenrollment, or study end. Kaplan Meier analysis for 3-year all-cause mortality was conducted by region: Midwest (reference group), Northeast, South, and West.

RESULTS: Among 24,586 HCM patients (49% female; 74.0% White; mean age 61.3 ± 14.9 years), 42.7% of patients resided in the Midwest (Northeast 27.1%; South 22.4%; West 7.8%). Northeast patients were less likely to receive beta-blockers, calcium channel blockers, and pacemaker but more likely to receive disopyramide (p<0.001). Patients in the South were less likely to receive beta-blockers (p<0.001) but more likely to receive calcium channel blockers, implantable cardioverter-defibrillators, pacemakers, and septal myectomy (all p<0.05). Patients in the West were less likely to receive beta-blockers but more likely to receive disopyramide (all p<0.01). Patients in the Northeast were less likely to experience AF, stroke, HF, and VF (all p<0.01) and patients in the West were less likely to experience stroke (p=0.020). Patients in the South were more likely to experience AF and HF (p<0.001). All-cause mortality rate was lowest in the Northeast (5.2%; p<0.001), with similar rates in the South (8.5%), West (8.3%), and Midwest (8.0%).

CONCLUSIONS: Incidence of adverse CV outcomes was less frequent in the Northeast and West and all-cause mortality was significantly lower in the Northeast. Further research is required to understand and address these regional differences.