Hypertension and diabetic retinopathy—what’s the story?

In type 1 diabetes the development of diabetic nephropathy may play a major role in the subsequent development of hypertension since microalbuminuria is present in about 80% of type 1 diabetic subjects before the onset of hypertension. 7 The pathogenesis of hypertension in type 2 diabetes is not so clear, with a lesser significance for nephropathy, with microalbuminuria predating hypertension in approximately 25% of type 2 diabetic subjects with hypertension. 7 Other relevant factors in type 2 diabetes are decreased baroceptor sensitivity, increased peripheral vascular resistance from enhanced smooth muscle contractility, and vascular structural changes including protein glycosylation and increased type IV collagen. 8 Additionally, hyperglycaemia causes increased function of the sodium/glucose proximal convoluted tubule co-transporter leading to sodium retention. The results of controlled prospective studies using antihypertensive agents to prevent the development of diabetic retinopathy have been awaited with interest. [...]1998 at least in type 2 diabetes the likely benefits of treatment of hypertension has been assumed from extrapolation of large treatment trials in non-diabetic subjects.