Impact of Improved Glycemic Control on Cardiac Function in Type 2 Diabetes Mellitus

Patients with type 2 diabetes mellitus are at risk of heart failure. Specific therapeutic interventions for diabetic heart disease are still elusive. We aimed to examine the impact of improved glycemic control on left ventricular (LV) function in these patients.

A total of 105 subjects with type 2 diabetes mellitus (aged 54±10 years) and poor glycemic control received optimization of treatment for blood glucose, blood pressure, and cholesterol to recommended targets for 12 months. LV systolic and diastolic function, measured by LV global longitudinal strain (GLS) and septal e' velocities, were compared before and after optimization. At baseline, patients had impaired LV systolic (GLS -14.9±3.2%) and diastolic function (e' 6.2±1.7 cm/s). After 12 months, glycated hemoglobin (HbA1c) decreased from 10.3±2.4% to 8.3±2.0%, which was associated with significant relative improvement in GLS of 21% and septal e' of 24%. There was a progressively greater improvement in GLS as patients achieved a lower final HbA1c. Patients achieving an HbA1c of <7.0% had the largest improvement. The 15 patients whose HbA1c worsened experienced a decline in GLS. Patients who improved their HbA1c by ≥1.0% had a significantly higher relative improvement in e' than those who did not (32% versus 8%; P=0.003). Baseline GLS, decrease in body mass index, and treatment with metformin were additional independent predictors of GLS improvement.

Improvements in glycemic control over a 12-month period led to improvements in LV systolic and diastolic function. This may have long-term prognostic implications.