Three echocardiographic phenotypes with distinct clinical profiles and outcomes were identified among patients with type 2 diabetes mellitus, according to a study published September 25 in the Journal of the American College of Cardiology.

Laura Ernande, MD, PhD, et al., used data from two large prospective cohorts of asymptomatic patients with type 2 diabetes mellitus who did not have overt heart disease for cluster analysis to link cardiac phenotypes and outcomes. The endpoint was a composite of cardiovascular mortality and hospitalization.

The study evaluated differences in clinical, biological and echocardiographic characteristics between patients with type 2 diabetes mellitus in relation to presence or absence of obesity and hypertension. Analyses also investigated the association between echocardiographic features and other phenotypic characteristics or major adverse cardiac events.

Patients with complete echocardiographic data were included (n = 745; 88 percent). Three clusters of cardiac phenotypes were identified. Cluster 1 (mostly males; lowest rates of obesity and hypertension) had the lowest left ventricular mass index (LVMi), E/e´ ratio, highest LV ejection fraction (LVEF) and second highest strain values. Cluster 2 (elderly, mostly female, most obesity and hypertension) had diastolic dysfunction with the highest strain values and E/e´ ratio but the lowest e´ velocities. Cluster 3 (mostly males, similar obesity and hypertension as cluster 1) had hypertrophic systolic dysfunction with the highest LVMi and LV volumes and lowest LVEF and strain.

At 67 months of follow-up, the composite endpoint occurred in 56 patients (10.8 percent), with the highest event rates in Cluster 2 and similar rates in Clusters 1 and 3. The prognosis was best in Cluster 1 (hazard ratio [HR], 1.00) compared with Clusters 2 (HR, 2.37) and 3 (HR, 2.19). A sensitivity analysis had findings similar with the main analysis.

This study showed that patients with the highest LVMi and volumes and the lowest LVEF and strain have the highest cardiovascular risk. "These findings confirmed the key role of echocardiography to detect early subtle systolic myocardial abnormalities and to better identify echocardiographic phenotypes in type 2 diabetes mellitus," concluded the authors.

According to an editorial comment by Maurizio Galderisi, MD, et al., the study results suggest the possibility that "reversible LV diastolic abnormalities, if not sustained by significant changes in cardiac structure, might be due to modifiable metabolic factors occurring in type 2 diabetes mellitus as well as hypertension and obesity." They proposed that women with type 2 diabetes mellitus could be more susceptible to metabolic management, whereas treatment with renin-angiotensin-aldosterone system drugs should be preferred in men of Cluster 3.