DETAIL Study: Diabetes Exposed to Telmisartan and Enalapril

• The key variable used to assess renal consequences was glomerular filtration rate (GFR). Change in this parameter after 5 years treatment provided the comparison between the two approaches of blocking the activity of the renin angiotensin system.
  

• Additional variables used to evaluate renal consequences of these two approaches of blocking the activity of the renin angiotensin system included glomerular filtration rates at earlier on-treatment timepoints and urinary albumin excretion rates
  

The aims of this study were to compare the renal consequences of two different approaches to blocking the activity of the renin angiotensin system - Angiotensin II antagonism with telmisartan and ACE inhibition with enalapril - in patients with hypertension and concurrent type II diabetes mellitus and diabetic nephropathy.

The study was designed to investigate albumin excretion rates in the short term, and in the longer term, to assess the outcome with respect to maintenance of renal function (GFR) and incidence of clinical endpoints.

Study Hypothesis:

Association of Hypertension and Diabetes Essential hypertension accounts for the majority of hypertension in people with diabetes, particularly in those with type II diabetes, who constitute more than 90% of those with a dual diagnosis of diabetes and hypertension.

Both diabetes and hypertension each confer increased cardiovascular risk, and patients with both conditions have more atherogenic risk factors.

Albumin Excretion as a Therapeutic Marker Microalbuminuria is an early and reliable predictor of diabetic nephropathy in both type I - insulin dependent diabetes mellitus (IDDM) and type II - non insulin dependent diabetes mellitus (NIDDM) patients, nephropathy being characterised by hypertension and an inevitable decline in renal function.

Furthermore, diabetic nephropathy is the single most important cause of end stage renal failure (ESRF) in the western world and over recent years the incidence of ESRF in patients with type II diabetes has dramatically increased.

In addition to predicting nephropathy, in type II diabetes, microalbuminuria also predicts mortality, the major causes of death being related to cardiovascular disease.

Comparison(s):

Selection of an ACE Inhibitor as the Comparative Agent Findings in preclinical studies of animals with diabetes mellitus suggest that ACE inhibitors reduce glomerular damage by one or more mechanisms independent of their antihypertensive effects. Glomerular efferent arteriolar tone is increased in diabetic animals and as a result there is an increase in transcapillary hydraulic pressure. These alterations may decrease the functional integrity of the glomerular capillary wall. In rats with diabetes, the long term administration of an ACE inhibitor diminishes the functional and morphologic evidence of glomerular injury and decreases glomerular transcapillary pressure. Removal of the tonic constrictor effect of angiotensin II on efferent arterioles would be expected to lower glomerular intracapillary pressure while preserving renal plasma flow.

Angiotensin II antagonists appear to be as effective as ACE inhibitors in delaying the progression of renal injury in animal models of diabetes.