In a Mayo Clinic study, HCM incidence has increased during the past several decades.

Hypertrophic cardiomyopathy (HCM) can cause exertional symptoms, such as chest pain or shortness of breath, heart failure, or even sudden cardiac death, but how common is it? In this epidemiologic study of HCM in Olmsted County, Minnesota (a Mayo Clinic location), researchers used a validated medical-record linkage system to evaluate the incidence and prevalence of HCM over time (1984–2015).

During the study period, 270 people received diagnoses of HCM, with a point prevalence of 89 per 100,000 population at the beginning of 2016. The most common symptom was dyspnea, and ≈61% of patients had evidence of left ventricular outflow tract obstruction. The incidence of HCM increased with each decade and was higher than the incidence in a previous study of the same community (1975–1984). Overall, patients with HCM had a higher standardized mortality than did the general population (hazard ratio, 1.44), but mortality among patients with HCM was lower with each decade.

COMMENT
This epidemiologic study takes advantage of the Rochester Epidemiology Project, which includes nearly every healthcare provider and more than 95% of residents in Olmsted County. Although generalizability of this one county to the diverse U.S. population is a limitation, the data suggest HCM’s incidence is increasing, likely due to a combination of greater awareness, better diagnostics, and a shift in diagnostic criteria over time. The good news is that HCM-related mortality also lessened over time, and editorialists remind us of effective therapies beyond β-blockers and calcium-channel blockers, including myectomy, septal exclusion, defibrillators, and more recently, disease-specific pharmacologic therapy, such as the myosin inhibitor mavacamten (Camzyos). — Kirsten E. Fleischmann, MD, MPH, FACC

Dr. Fleischmann is Professor of Clinical Medicine in the Division of Cardiology at the University of California San Francisco School of Medicine and Medical Director of the Cardiac Stress Laboratory at the UCSF Medical Center.

Karim S et al. Re-evaluating the incidence and prevalence of clinical hypertrophic cardiomyopathy. Mayo Clin Proc 2024 Mar; 99:362. (https://doi.org/10.1016/j.mayocp.2023.09.009)

Reddy YNV. Heart failure and hypertrophic cardiomyopathy — Looking back on decades of remarkable progress. Mayo Clin Proc 2024 Mar; 99:352. (https://doi.org/10.1016/j.mayocp.2024.01.009)

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