Impact of Diabetes Mellitus on Left Ventricular Mechanics and Long-Term Outcome in Patients with Hypertrophic Cardiomyopathy

Background

Type 2 diabetes mellitus (T2DM) intensifies the clinical symptoms of heart diseases and leads to a worse prognosis in heart failure patients. Although hypertrophic cardiomyopathy (HCM) and DM rarely co-occur, particularly in older individuals, the impact of DM on cardiac function and outcomes in individuals with HCM remains insufficiently understood.

Methods

A total of 421 HCM patients were included and followed up in a prospective cohort study (mean 68.7 months). In the diabetic HCM group (n = 47), patients had a mean age of 47 ± 17 years, and 31 (66%) were male, while the non-diabetic HCM group (n = 374) had a mean age of 44 ± 14 years, and 246 (65%) were male. At study entry, all patients underwent echocardiographic evaluation, encompassing left ventricular (LV) regional and global longitudinal strain (GLS), as well as strain rate (SR) analysis.

Results

In diabetic HCM, there was a greater prevalence of hypertension (p < 0.0001), while the ratio of septal to posterior wall thickness (PWT) (p < 0.003) and E' value were lower (p < 0.009) compared to non-diabetic HCM. No significant difference between groups in NYHA class or cardiac phenotype. Diabetic HCM exhibited notable reductions in GLS (p < 0.02), systolic SR (SRsys) (p < 0.04), and early diastolic SR (SRe) p < 0.006. Additionally, there was a significant inverse correlation between LVGLS and HbA1c levels (r = −0.58, p < 0.0001), and the duration of diabetes (r = −0.39, p < 0.006). Hospitalization rates were greater in the diabetic HCM than in the non-diabetic group (44.7% vs.19.5%, p < 0.001). Among all demographic characteristics, phenotypic data, conventional echocardiographic measurements, and LV mechanics, diabetes emerged as the sole determinant of hospitalization among HCM patients. The presence of diabetes nearly tripled the odds of hospitalization (odds ratio: 2.813 [1.448–5.465], p < 0.002). However, diabetes did not negatively affect long-term survival, and age remained the only independent predictor of all-cause mortality.

Conclusions

In HCM, T2DM is linked to more deterioration of cardiac mechanics and contributes to unfavorable consequences by frequent hospitalization on its own, independent of age, comorbidities, or phenotype.