Comparison 2. Insulin monotherapy versus insulin plus metformin.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Weight (change from baseline)	7	615	Mean Difference (IV, Random, 95% CI)	‐2.12 [‐3.19, ‐1.05]
1.1 Parallel‐group trials	6	577	Mean Difference (IV, Random, 95% CI)	‐2.45 [‐3.61, ‐1.29]
1.2 Cross‐over trials	1	38	Mean Difference (IV, Random, 95% CI)	‐0.5 [‐2.11, 1.11]
2 Weight (change from baseline) [kg] GIV	7		Mean Difference (Random, 95% CI)	‐2.11 [‐3.18, ‐1.05]
2.1 Parallel‐group	6		Mean Difference (Random, 95% CI)	‐2.45 [‐3.61, ‐1.29]
2.2 Cross‐over group	1		Mean Difference (Random, 95% CI)	‐0.5 [‐2.05, 1.05]
3 HbA1c (change from baseline)	9	698	Mean Difference (IV, Random, 95% CI)	‐0.86 [‐1.20, ‐0.51]
3.1 Parallel‐group trials	7	634	Mean Difference (IV, Random, 95% CI)	‐0.77 [‐1.13, ‐0.41]
3.2 Cross‐over trials	2	64	Mean Difference (IV, Random, 95% CI)	‐1.16 [‐2.13, ‐0.19]
4 HbA1c (change from baseline) [%] GIV	9		Mean Difference (Random, 95% CI)	‐0.86 [‐1.20, ‐0.51]
4.1 Parallel‐group	7		Mean Difference (Random, 95% CI)	‐0.77 [‐1.13, ‐0.41]
4.2 Cross‐over group	2		Mean Difference (Random, 95% CI)	‐1.16 [‐2.13, ‐0.18]
5 Total cholesterol (change from baseline)	8	651	Mean Difference (IV, Random, 95% CI)	‐0.25 [‐0.41, ‐0.08]
5.1 Parallel‐group trials	6	587	Mean Difference (IV, Random, 95% CI)	‐0.20 [‐0.38, ‐0.02]
5.2 Cross‐over trials	2	64	Mean Difference (IV, Random, 95% CI)	‐0.47 [‐0.85, ‐0.09]
6 Total cholesterol (change from baseline) [mmol/L] GIV	8		Mean Difference (Random, 95% CI)	‐0.29 [‐0.50, ‐0.07]
6.1 Parallel‐group	6		Mean Difference (Random, 95% CI)	‐0.20 [‐0.38, ‐0.02]
6.2 Cross‐over group	2		Mean Difference (Random, 95% CI)	‐0.57 [‐0.94, ‐0.20]
7 HDL‐cholesterol (change from baseline)	8	651	Mean Difference (IV, Random, 95% CI)	‐0.01 [‐0.06, 0.04]
7.1 Parallel‐group trials	6	587	Mean Difference (IV, Random, 95% CI)	‐0.00 [‐0.05, 0.05]
7.2 Cross‐over trials	2	64	Mean Difference (IV, Random, 95% CI)	0.00 [‐0.25, 0.25]
8 HDL‐cholesterol (change from baseline) [mmol/L]	8		Mean Difference (Random, 95% CI)	0.01 [‐0.05, 0.08]
8.1 Parallel‐group	6		Mean Difference (Random, 95% CI)	‐0.00 [‐0.05, 0.05]
8.2 Cross‐over group	2		Mean Difference (Random, 95% CI)	0.04 [‐0.22, 0.31]
9 Triglycerides (change from baseline)	8	651	Mean Difference (IV, Random, 95% CI)	‐0.09 [‐0.22, 0.04]
9.1 Parallel‐group trials	6	587	Mean Difference (IV, Random, 95% CI)	‐0.07 [‐0.24, 0.11]
9.2 Cross‐over trials	2	64	Mean Difference (IV, Random, 95% CI)	‐0.17 [‐0.50, 0.16]
10 Triglyceride (change from baseline) [mmol/L] GIV	8		Mean Difference (Random, 95% CI)	‐0.15 [‐0.41, 0.11]
10.1 Parallel‐group	6		Mean Difference (Random, 95% CI)	‐0.07 [‐0.24, 0.11]
10.2 Cross‐over group	2		Mean Difference (Random, 95% CI)	‐0.34 [‐0.79, 0.11]