The impact of diabetes mellitus on the clinical phenotype of hypertrophic cardiomyopathy

Aims: Diabetes mellitus (DM) aggravates the clinical features of ischaemic and hypertensive heart diseases and worsens the prognosis of heart failure patients. Hypertrophic cardiomyopathy (HCM) and diabetes coexist fairly frequently in elderly patients but the impact of DM on the clinical phenotype of HCM is yet unknown. We sought to describe if predominant features of heart failure in DM patients exist independently in HCM.

Methods and results: We reviewed clinical characteristics of 937 patients, age ≥40, diagnosed with HCM, from two tertiary medical centres in Spain and Israel. A propensity score matched cohort of 294 patients was also analysed. Our cohort comprised 102 HCM patients with diabetes (8.7%). Patients with DM were older at diagnosis {median 56 [interquartile range (IQR) 47-67] vs. 53 (IQR 43-63), P = 0.02} and had a higher prevalence of comorbidities. Hypertrophic cardiomyopathy patients with DM had a higher prevalence of diastolic dysfunction, pulmonary hypertension, significant mitral regurgitation, and pacemaker implantation. Hypertrophic cardiomyopathy patients with DM had a higher New York Heart Association (NYHA) class (P < 0.001) and lower exercise capacity [7.0 METS (IQR 5.0-10.0) vs. 9.0 METS (IQR 6.6-11.0), P = 0.002]. These findings were independent of age, gender, country of origin, hypertension, and coronary artery disease. Patients with diabetes had a significantly higher 15-year mortality (22% vs. 15%, P = 0.03), with no differences in sudden cardiac death, appropriate implanted cardioverter-defibrillator therapy, or heart transplantation.

Conclusion: Hypertrophic cardiomyopathy patients with diabetes are older and have a higher cardiovascular risk profile. They have a lower functional capacity and more heart failure symptoms due to diastolic dysfunction.