Table 3.

The results of subgroup analysis

Subgroup	Studies	Heterogeneity analysis	OR	P value
Population
Asian	14	91%, P < 0.00001	1.08 [0.74, 1.57]	0.69
European	1	/	3.29 [2.17, 4.99]	P < 0.00001
Year
Before 2015	6	67%, P = 0.006	1.76 [1.06, 2.92]	0.03
After 2015	9	95%, P < 0.00001	0.92 [0.56, 1.52]	0.75
Sex
Female	6	97%, P < 0.00001	2.21 [0.62, 7.83]	0.22
Male	3	83%, P = 0.003	1.02 [0.31, 3.39]	0.97
Economic Level
Developed countries	5	89%, P < 0.00001	0.98 [0.49, 1.96]	0.95
Developing countries	10	93%, P < 0.00001	1.28 [0.80, 2.07]	0.31
Diabetes type
T1DM	1	/, P = 0.002	3.83 [1.64, 8.96]	0.002
T2DM	3	98%, P < 0.00001	0.69 [0.11, 4.55]	0.70
Quality
Over 7 points	13	91%, P < 0.00001	0.89 [0.67, 1.17]	0.40
Below 7 points	6	86%, P < 0.00001	1.71 [1.19, 2.45]	0.004

OR odds ratio, T2DM type 2 diabetes mellitus, T1DM type 1 diabetes mellitus