Clinical question
What are the effects of controlling blood pressure levels of people with diabetes on the incidence and progression of diabetic retinopathy and preservation of visual acuity?
Bottom line
Among the 11 trials reporting the incidence of diabetic retinopathy in 4940 participants, findings supported intensive blood pressure intervention, with an estimated reduction in 5-year incidence of 18%. This was particularly relevant for participants with type 2 diabetes who were hypertensive at study enrolment. A study of normotensive people with type 1 diabetes also showed a decrease in the incidence of diabetic retinopathy for those receiving blood pressure control, but more research is required to confirm this finding.
Five trials including 5144 participants with diabetes reported on the progression of retinopathy. Overall, the evidence indicated no benefit of more intensive intervention for blood pressure with respect to the progression of diabetic retinopathy.
Caveat
There was considerable variability among the trials with respect to sample size, blood pressure control interventions, eligibility criteria, diabetic retinopathy outcomes reported, years during which trials had been conducted and length of follow-up of the participants.
The investigators of the clinical trials included in this review did not systematically report on adverse events related to tight blood pressure control, apart from death from any cause.
Context
Diabetic retinopathy is a common complication of diabetes and a leading cause of visual impairment and blindness. Research has established the importance of blood glucose control to prevent the development and progression of the ocular complications of diabetes. Concurrent blood pressure control has been advocated for this purpose, but individual studies have reported varying conclusions regarding the effects of this intervention.
Cochrane Systematic Review
Do DV, et al. Blood pressure control for diabetic retinopathy. Cochrane Database Syst Rev 2023;3:CD006127. This review contains 29 trials with a total of 4620 participants with type 1 diabetes and 22,565 participants with type 2 diabetes.
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