Comparison 3. Outcomes by blood pressure status at entry: More blood pressure control versus no (or less) control.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
3.1 Incidence of diabetic retinopathy by 5 years	11	4940	Risk Ratio (M‐H, Random, 95% CI)	0.82 [0.73, 0.92]
3.1.1 Normotensive or treated hypertensive	5	2966	Risk Ratio (M‐H, Random, 95% CI)	0.85 [0.76, 0.95]
3.1.2 Hypertensive	6	1974	Risk Ratio (M‐H, Random, 95% CI)	0.75 [0.57, 0.98]
3.2 Progression of diabetic retinopathy by 5 years	5	5144	Risk Ratio (M‐H, Random, 95% CI)	0.94 [0.78, 1.12]
3.2.1 Normotensive or treated hypertensive	3	4365	Risk Ratio (M‐H, Random, 95% CI)	1.01 [0.87, 1.18]
3.2.2 Hypertensive	2	779	Risk Ratio (M‐H, Random, 95% CI)	0.73 [0.51, 1.06]
3.3 Combined incidence and progression of diabetic retinopathy by 5 years	8	6212	Risk Ratio (M‐H, Random, 95% CI)	0.78 [0.68, 0.89]
3.3.1 Normotensive or treated hypertensive	3	1966	Risk Ratio (M‐H, Random, 95% CI)	0.81 [0.57, 1.15]
3.3.2 Hypertensive	5	4246	Risk Ratio (M‐H, Random, 95% CI)	0.77 [0.67, 0.89]
3.4 Incidence of PDR, CSME, or VH by 5 years	9	8867	Risk Ratio (M‐H, Random, 95% CI)	0.79 [0.59, 1.08]
3.4.1 Normotensive or treated hypertensive	5	4588	Risk Ratio (M‐H, Random, 95% CI)	1.00 [0.83, 1.19]
3.4.2 Hypertensive	4	4279	Risk Ratio (M‐H, Random, 95% CI)	0.52 [0.33, 0.84]
3.5 Adverse effect: death, 4 to 9 years	13	13979	Risk Ratio (M‐H, Random, 95% CI)	0.87 [0.76, 1.00]
3.5.1 Normotensive or treated hypertensive	6	6207	Risk Ratio (M‐H, Random, 95% CI)	0.90 [0.67, 1.21]
3.5.2 Hypertensive	7	7772	Risk Ratio (M‐H, Random, 95% CI)	0.86 [0.74, 1.01]