To investigate the efficacy and safety of liraglutide versus sitagliptin in obese patients with inadequately controlled type 2 diabetes with insulin therapy.

Ninety-eight cases of type 2 diabetic with body mass index(BMI)>25 kg/m², waist circumference(male>90 cm and female> 85 cm), glycated hemoglobin A_1c(HbA_1c) 7.5%-9.5% were enrolled from February 2013 to February 2014 in Quanzhou First Hospital Affiliated to Fujian Medical University. All subjects who received metformin (at least 1 000 mg/d) and insulin (at least 45 U/d) for at least 6 months were numberally randomly assigned to receive additional liraglutide (0.6 mg for one week followed by 1.2 mg later) once a day (n=48) or sitagliptin 100 mg once a day(n=50) in a 16-week study. Participants were evaluated for glycaemic control, weight, blood pressure, lipid profiles, and adverse events at baseline and 16 weeks. Paired t test was used to analyze changes within groups. Two-sample t test was applied to compare differences of continuous variables between groups. Rates were compared by using the Chi-Square test.

Compared to the baseline, after 16-week treatment, the HbA_1c decreased for 1.4%±0.4% in liraglutide group and for 1.2%±0.4% in sitagliptin group(t=2.5, P<0.05). The proportion of patients whose HbA_1c reached the target of less than 7.0% was 53.7% and 37.2% in the liraglutide group and sitagliptin group, respectively(χ²=2.3, P>0.05). After 16-week treatment, weight loss for (2.5±2.4) kg was observed in the liraglutide group, while weight gain was reported in the sitagliptin group for (0.3±1.2) kg(t=6.8, P<0.01). After 16-week treatment, systolic blood pressure in the liraglutide group reduced for (7.3±6.5) mmHg and for (1.7±3.7) mmHg in sitagliptin group(t= 4.8, P<0.01). The improvement of lipid profile, homocysteic acid and diastolic blood pressure after the treatment were all statistically significant in the two groups (all P<0.05), but there was no significant difference in change values of those indexes between the two groups (all P>0.05). The incidence of gastrointestinal adverse events was greater in the liraglutide group than that in sitagliptin group.

Liraglutide and sitagliptin applied to patients with inadequately glycemic controlled and obese type 2 diabetes with insulin therapy can beneficial to regulate glucose. Liraglutide is superior on glucose control and drop of weight and systolic blood pressure to sitagliptin. Stagliptin leads to fewer gastrointestinal effects than liraglutide.

Diabetes mellitus, type 2; Obesity; Insulin; Liraglutide; Stagliptin