Subclinical cardiovascular dysfunction in adults with type 2 diabetes: characterisation and lifestyle interventions

Background

People with type 2 diabetes (T2D) are at increased risk of heart failure. Various measures of subclinical cardiovascular dysfunction have been reported, but it is unclear how these relate to functional limitation or whether they are reversible with lifestyle interventions.

Objectives

To comprehensively describe cardiovascular function in a multi-ethnic, asymptomatic population with T2D, and determine whether this is improved by a low-energy meal replacement plan (MRP) diet or exercise.

Methods

A comparison of adults with and without T2D and no cardiovascular disease was undertaken. A subset undertook a prospective, randomised, open-label, blinded endpoint (PROBE) trial and were assigned a 12-week intervention of: 1) routine care; 2) supervised exercise or 3) MRP. Echocardiography, cardiopulmonary exercise testing and cardiovascular magnetic resonance (CMR) were performed at baseline and post-intervention. The primary outcome was change in left ventricular (LV) peak early diastolic strain rate (PEDSR), measured by CMR.

Results

At baseline, 247 adults with T2D and 78 controls were compared. Subjects with T2D had concentric LV remodelling, diastolic dysfunction, aortic stiffening, reduced myocardial perfusion, and markedly lower peak VO2. Key clinical determinants of cardiovascular dysfunction were diabetes duration, body mass index (BMI), smoking history, and systolic blood pressure (BP). MPR and diastolic filling were independently associated with peak VO2.

Seventy-six T2Ds completed the PROBE trial (30 routine care, 22 exercise, and 24 MRP). The MRP arm lost weight, improved BP, glycaemia, LV mass:volume, and aortic stiffness. The exercise arm had negligible weight loss but increased exercise capacity. PEDSR increased in the exercise arm versus routine care (p=0.002) but did not improve with the MRP compared to routine care.

Conclusions

Concentric LV remodelling, diastolic dysfunction, aortic stiffening, and reduced MPR are key components of subclinical cardiovascular dysfunction in T2D. Exercise training improved diastolic function and despite beneficial effects on weight, glycaemic control, concentric LV remodelling and aortic stiffness, an MRP did not improve diastolic function.