https://diabetes.acponline.org/archives/2015/07/10/5.htm

Review: Intensive blood pressure control reduces retinopathy in diabetes

Intensive control of blood pressure reduced incidence of retinopathy, but not progression of established retinopathy, in patients with type 1 or 2 diabetes, according to an analysis of 15 randomized controlled trials.


Intensive control of blood pressure (BP) reduced incidence of retinopathy, but not progression of established retinopathy, in patients with type 1 or 2 diabetes, according to an analysis of 15 randomized controlled trials (RCTs). The patients receiving intensive control also had higher rates of hypotension than those on placebo, less intensive control, or usual care, according to the analysis, which included more than 13,000 patients.

The review was published in the Cochrane Database of Systematic Reviews on Jan. 31, 2015. The following commentary by Steven A. Smith, MD, and Shrikant Tamhane, MD, was published in the ACP Journal Club section of the June 16, 2015, Annals of Internal Medicine.

The rigorous Cochrane review by Do and colleagues addresses the complex role of BP control on diabetic retinopathy. Blood glucose control reduces risk for diabetic retinopathy and slows progression in patients with the condition. The review indicates that the evidence for intensive BP control on incidence and progression of retinopathy is weak due to variability in study designs, populations, interventions, and outcomes. Intensive BP control reduces incidence of diabetic retinopathy in the initial 4 to 5 years of treatment, but there is no clear evidence on beneficial effects on the progression of diabetic retinopathy.

The review included studies with heterogeneous groups of patients and provided subgroup results by type of diabetes and hypertension but not by such factors as duration of diabetes or BP targets. Also, the possibility of bias exists due to pharmaceutical company sponsorship of 6 RCTs and the unclear involvement of such sponsors in 7 additional RCTs.

Diabetic retinopathy is complex, and further study is needed to increase our understanding of the condition, including which subgroups of patients with diabetes may benefit from current specific antihypertensive medications and BP targets.

Despite the lack of conclusive evidence of a protective effect on retinopathy, early treatment of hypertension is important in patients with diabetes, both to prevent cardiovascular disease and to minimize progression of renal disease.