Table 2. Studies included in the present review.

Studies	Patients	Intervention	Control	Major Outcomes	Ethnicity	Findings
1). Kaku et al, 2010	264 patients on a SUa (glibenclamide, glicazide or glimeprimide)	Liraglutide 0.6 mg daily or 0.9 mg daily	Placebo with no active ingredients	1). Change of HbA1c at 24 wks	Japanese	−1.46% to −1.56% (liraglutide)vs. −0.40% (placebo)
				2). Proportion reaching HbA1c<7.0%		46.5% to 71.3% (liraglutide) vs. 14.8% (placebo)
2). Seino et al, 2012b	267 patients aged ≥20 years with suboptimal glycaemic control (HbA1c 7.4% to <10.4%)	Liraglutide 0.6 mg or 0.9 mg daily	Placebo with no active ingredients	Change of HbA1c at 24 wks	Japanese	Mean HbA1c was reduced by 1.00% to 1.27% points than placebo.
3). Kadowaki et al, 2011	179 patients who had suboptimal glycaemic control despite use of SUa alone or in combination with a biguanide or thiazolidinedione	Exenatide 5 µg BID or 10 µg BID offered subcutaneously	Placebo with no active ingredients	Change of HbA1c at 24 wks	Japanese	−1.34% to −1.62% (exenatide) vs. −0.28% (p<0.001)
4). Inagaki et al, 2012	427 patients aged ≥20 years with insufficient glucose control	Exenatide QW 2 mg daily	Once daily insulin glarigine (starting dose 4U)	Change of HbA1c at 26 wks	Japanese	−1.11% (exenatide QW) vs. −0.68% (insulin Glargine), p<0.001 with the 95% C.I. upper limit <predefined non-inferiority margin (0.4%)
5). Seino et al, 2012a	311 patients aged 25–81 years with Hba1c between 7–10% and on basal insulin +/− SUa	Lixisenatide starting from 10 µg to 15 µg and 20 µg	Placebo with no active ingredients	Change of HbA1c at 24 wks	Japan, Republic of Korea, Taiwan, the Phillipines	−0.77% (lixisenatide) vs. 0.11% (placebo) (p<0.0001)
6). Inagaki et al, 2013	618 patients aged ≥20 years on SUa or A-GIb	Linagliptin 5 mg daily	Metformin BD or TDS, up to 2,250 mg/day	1). Change of HbA1c at 52 wks	Japanese	1). −0.7% to −0.9% (linagliptin) vs. −0.8% to −1.0% (metformin), p = NSc
				2).Hypoglycaemic attack rates		2). 1.6% to 13.7% (linagliptin) vs. 3.2% to 15.9% (metformin); p = NSc
7). Zeng et al, 2013	192 patients on metformin and a SUa	Linagliptin 5 mg daily	Placebo with no active ingredients	1). Change of HbA1c at 24 wks	Chinese	1). −0.59% (linagliptin) vs. 0.08% (placebo), p<0.0001
				2). Change in FPG		2). −3.9 mg/dL (linagliptin) vs. 15.0% (placebo), p<0.001
				3). Adverse event rates		3). 38.9% (linagliptin) vs. 43.8% (placebo), p = NSc
8). Takihata et al, 2013	115 patients inadequately controlled with metformin and/or sulphonylurea	Sitagliptin 50 mg daily	Pioglitazone 15 mg daily	Change of HbA1c at 24 wks	Japanese	−0.86 (SD 0.63%) (sitagliptin) vs. −0.58 (SD 0.68%) (pioglitazone), p = 0.024
9). Seino et al, 2012	312 Patients on glimepiride (1–4 mg/day) with poor glycaemic control	Alogliptin 12.5 mg or 25 mg	Placebo with no active ingredients	1). Change of HbA1c at 12 wks	Japanese	1). −0.59% to −0.65% (alogliptin) vs. 0.35% (placebo)
				2). Adverse events		2). Comparable event rates with the majority being mild

^aSU =  sulphonylurea.

^bA-GI =  α-glucosidase inhibitors.

^cNS =  Non-significant.