ABSTRACT
In people with type 2 diabetes (T2DM), hyperglycemia has a negative impact on cardiac function and cardiovascular risk. Beneficial effects of improved postprandial glycemic control have been shown for cardiovascular risk only. To demonstrate these beneficial effects on myocardial function, we investigated well-controlled T2DM patients on three insulin regimens with different impact on postprandial glucose control. For 24 months, 61 T2DM participants in a randomized study had either conventional therapy (CT) with human premixed insulin b.d. (n=20), intensified therapy (ICT) with Lispro at meals and NPH at bedtime (n=24), or supplementary therapy (SIT) with human regular insulin at meals (n=17). Metabolism and cardiovascular function were assessed before and 2 hours after a standardized carbohydrate breakfast (48 g) using tissue Doppler to measure diastolic myocardial function (E'). Age, BMI, dose of insulin, cardiovascular disease, and medication were comparable between the groups. Hb1Ac was comparable with CT, ICT, and SIT (6.6+/-0.6, 6.2+/-0.6, and 6.4+/-0.7%) and so was fasting glucose. Post-meal glucose increment was 60+/-45 mg/dl with CT, but 15+/-52 and 8+/-58 mg/dl with ICT and SIT (p<0.006). E' was significantly lower (p<0.03) with CT (6.8+/-1.0 cm/s) vs. ICT (7.7+/-1.6) and SIT (7.8+/-1.2 cm/s), and correlated with post-meal glucose (r=-0.2644, p<0.046). Intima-media thickness and arterial stiffness parameters were higher in CT (p<0.04). In T2DM patients, the long-term insulin regimens CT, ICT, and SIT achieved overall good metabolic control with significant differences, however, in postprandial glucose increments. The regimens achieving better post-meal glucose control were associated with better myocardial/vascular function.
