To assess the effect of the GLP-1 analogue liraglutide on measures of cardiac function and physical performance in patients with type 2 diabetes (T2D).

In this phase-IV randomized double-blind placebo-controlled parallel-group clinical trial at a tertiary hospital, T2D patients with HbA_1c levels of 7–10% with oral agents and/or intermediate-/long-acting insulin were allocated (computer-generated randomization, ratio 1:1) to either liraglutide 1.8 mg/day or a placebo for 6 months. The primary endpoint was maximum oxygen consumption (VO_2max) during cycle ergometry, while other procedures included a 6-min walk test, echocardiography, anthropometry and blood tests. Safety endpoints were also monitored, and an intention-to-treat analysis was performed.

A total of 24 patients (15 women) aged 52 (11.7) years, with diabetes duration of 8.7 (5.8) years, BMI 34.98 (6.2) kg/m² and HbA_1c 8.2% (0.68%), were randomized to liraglutide 1.8 mg daily or placebo. There were no differences in VO_2max [17.98 (4.8) vs. 15.90 (4.96) mL/kg/min; P > 0.10], VE/VCO₂ slope [30.18 (4.8) vs. 32 (4.49)], left ventricular ejection fraction or 6-min walk test [530.7 (86) vs. 503.9 (84) m] at 6 months. HbA_1c was lower (6.7% vs. 7.7%; P =  0.005), with a trend towards lower maximum systolic blood pressure during ergometry [171.7 (24.4) vs. 192.5 (25.6); P = 0.052] in the liraglutide group at the end of the study. There were no severe adverse events.

In this trial, liraglutide improved glycaemic control in T2D, but had no significant effects on either physical performance or myocardial function.