Table 5

Subgroup analyses for all-cause mortality

Outcomes	Variable	Group	Number of cohorts	RRR and 95% CI	P value	I² (%)	P value for heterogeneity	P value for meta-regression
All-cause mortality	Publication year	Before 2010	7	1.51 (1.23 to 1.85)	<0.001	38.2	0.138	–
	Publication year	2010 or after	0	–	–	–	–	–
	Country	Western	6	1.63 (1.41 to 1.88)	<0.001	8.2	0.364	0.039
	Country	Eastern	1	0.71 (0.33 to 1.55)	0.394	–	–	0.039
	Sample size	≥10 000	3	1.66 (1.46 to 1.90)	<0.001	0.0	0.772	0.050
	Sample size	<10 000	4	1.06 (0.59 to 1.90)	0.844	43.7	0.149	0.050
	Assessment of DM	Self-reported	2	1.69 (1.46 to 1.95)	<0.001	0.0	0.669	0.123
		Measured	4	1.06 (0.59 to 1.90)	0.844	43.7	0.149
		Both	1	1.50 (1.03 to 2.19)	0.035	–	–
	Follow-up duration (years)	≥10	7	1.51 (1.23 to 1.85)	<0.001	38.2	0.138	–
	Follow-up duration (years)	<10	0	–	–	–	–	–
	Adjusted other CVD risk factors	Yes	4	1.50 (1.12 to 2.01)	0.006	39.4	0.176	0.850
	Adjusted other CVD risk factors	No	3	1.33 (0.75 to 2.36)	0.321	57.6	0.095	0.850
	Study quality	High	2	1.69 (1.41 to 2.02)	<0.001	0.0	0.490	0.414
	Study quality	Low	5	1.25 (0.80 to 1.94)	0.329	53.3	0.073	0.414