Comparing effectiveness and safety of combined insulin aspart 30 and metformin compared to insulin aspart 30 alone in patients with type 2 diabetes and different heart disease risk profiles

This study compared the effectiveness and safety of biphasic insulin aspart 30 (BIAsp 30; NovoMix 30) alone or with metformin (Glucophage), in patients with inadequately controlled type 2 diabetes (T2D). The authors concluded that combined therapy may be preferred in patients with high cardiovascular risk and/or a body mass index (BMI; a measure of body weight in relation to height) of 26 kg/m² or less.

Effective T2D management involves lowering glycated hemoglobin (HbA1c) levels (blood glucose control for the past 2-3 months). Although metformin tablets are the first treatment line for patients with T2D, many patients eventually need insulin therapy to effectively manage their blood glucose levels. One commonly used insulin is BIAsp 30.

T2D is often associated with overweight (a BMI between 25 and 29.9 kg/m²) or obesity (a BMI of 30 kg/m² or higher) and cardiovascular disease (CVD). It has been reported that metformin treatment may reduce the risk of CVD in patients with T2D. However, whether BIAsp 30 with or without metformin has any effect in patients with T2D and different CVD risk profiles and different BMIs is currently not known.

257 patients with T2D were included in this study. They were randomly assigned to 2 groups. Group 1 included 130 patients that received BIAsp 30 and metformin. Group 2 included 105 patients who received BIAsp 30 alone. The study was done over 16 weeks. Patients' BMI and CVD risk were calculated.

A significantly higher percentage of patients with high cardiovascular risk that received combined therapy achieved an HbA1c target of less than 7% (54.55%), compared to those given BIAsp 30 alone (34.78%).

47.83% of patients with a BMI of 26 kg/m² or less that received combined therapy achieved the HbA1c target below 7% compared to 28.17% of those that received BIAsp 30 alone. Also, 20.29% of patients with a BMI of 26 kg/m² or less in group 1 achieved an HbA1c level of less than 7% without hypoglycemia ()dangerously low blood glucose levels) or weight gain, compared to 6.85% of patients in group 2. Slightly better safety was observed in patients treated with combined therapy.

The study found that patients who had a high CVD risk and/or a body mass index (BMI) of 26 kg/m² or less, may benefit from combined therapy with BIAsp 30 and metformin over BIAsp 30 alone.

The original study design was not intended to evaluate the outcomes based on CVD risk and BMI. Also, the study period was rather short. This study was done in a Chinese population, therefore the results may not apply to a global population.