Low Dose Versus Aggressive Inhibition of the Renin-Angiotensin-Aldosterone (RAS) to Treat Microalbuminuria

Not Applicable

Completed

Conditions: Microalbuminuria

Interventions: Drug: benazepril

Registration Number: NCT00907374

Lead Sponsor: Charles Drew University of Medicine and Science

Brief Summary: The objective of the study is to assess the effect of standard versus aggressive inhibition of the renin-angiotensin system (RAS)in type 2 diabetic patients with microalbuminuria (MA) on; a)progression of microalbuminuria, b)estimated glomerular filtration rate (eGFR), c)endothelial dysfunction (measured by post-hyperemia arterial tonometry) and d)the slowing of the progression of atherosclerotic disease (measured by carotid intima media thickness \[CIMT\]).

Detailed Description: Diabetic patients with confirmed MA (50-300 mg albumin per g creatinine) on a morning spot urine sample were entered into a one to three month run-in phase before randomization. (50 mg/g was used as the lower limit to allow room for improvement to reach normal.) Since hypertension and uncontrolled hyperglycemia will cause MA, blood pressure (BP) and hemoglobin A1c (AIC) levels were reduced to \<130/80 mm Hg and \<8.0%, respectively, during this period. All patients had been on various doses of an angiotensin converting enzyme inhibitor (ACE-I) which were reduced to 10 mg benazepril and BP controlled with other classes of anti-hypertensive drugs (except for angiotensin receptor blockers \[ARB's\]). Glycemia was treated with intensification of their current therapy. MA and BP were measured monthly.

When goal levels of BP and AIC were achieved and MA was still present, patients were randomized to either low dose RAS inhibition (10 mg benazepril) (Standard) or aggressive inhibition of the RAS (Aggressive). MA continued to be measured monthly and the progressive increase in doses of an ACE-I and an ARB was as follows. Benazepril (the ACE-I) - 10 mg to 20 mg to 40 mg to adding losartan (the ARB) -25 mg to 50 mg to 100 mg to increasing benazepril to 80 mg with the goal of returning albumin excretion to normal. Other classes of drugs were reduced as necessary to keep systolic BP \> 100 mm Hg. Serum creatinine and potassium\[K+\] were measured monthly, AIC levels every 3 months and CIMT by ultrasound and endothelial function by post hyperemia and nitroglycerine (NTG) - induced peripheral artery tonometry (PAT) via finger plethysmography every six months.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 46

Inclusion Criteria

Males and females, age 18-70
Subjects with diabetic renal disease as defined by spot urine albumin - creatinine ratio 30-300mg/g and estimated glomerular filtration rate of >60 ml/min

Exclusion Criteria

Intake of non-steroidal anti-inflammatory agents (NSAIDs) more than 15 days/month, excluding aspirin.
Inability to discontinue NSAIDs or aspirin for 5 days prior to GFR measurement.
History of severe adverse reaction to any of the randomized drugs required for use in the protocol or contraindication of their use.
Participation in another intervention study.
Pregnancy or likelihood of becoming pregnant during the study period; lactation
Clinical and laboratory evidence of any renal disease other than diabetic nephropathy.
History of drug abuse in the past 2 years, including narcotics, cocaine or alcohol (> 21 drinks per week). Serious systemic disease that might influence survival or the course of renal disease. (Chronic oral steroid therapy is exclusion, but steroid-containing nasal sprays are not. Inactive sarcoidosis is not an exclusion).
History of malignant or accelerated hypertension within 6 months prior to study entry; previous chronic peritoneal or hemodialysis or renal transplantation. Known secondary causes of hypertension. Spot urine albumin - creatinine ratio exceeding 300 (mg/g)
Serum potassium level > 5.5 mEq/L for those not on ACE inhibitors during Baseline, or serum potassium level > 5.9 mEq/L for those on ACE inhibitors during Baseline.

Leukopenia < 2,500/mm3 at screening and confirmed at the end of Baseline.

Doubt that the participant will be able to adhere to medications or comply with the protocol visit schedule
Arm Circumference > 52 cm, which precludes measuring blood pressure with the "thigh" blood pressure cuff. Arm length such that if the cuff circumference extended into the antecubital space so that the cuff interfered with placement of the stethoscope over the brachial artery for blood pressure measurement
Clinical evidence of lead intoxication. Clinical evidence of congestive heart failure, current or within the preceding six months. Ejection fraction below 35% measured by any method. Heart block greater than first degree or any other arrhythmia that contraindicated the use of any of the primary BP drugs.

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Agressive inhibition of the RAS	benazepril	40-80 mg benazepril plus 25-100 mg losartan both orally once or twice daily
Low dose inhibition of RAS	benazepril	Standard low dose inhibition of the RAS with 10 mg of benazepril orally daily to treat microalbuminuria

Primary Outcome Measures

Name	Time	Method
Microalbuminuria Reported as Urinary Albumin:Creatinine Ratio	3 to 36 months	Average of ratio for all participants during the 3-36 months of the study

Secondary Outcome Measures

Name	Time	Method
Estimated Glomerular Filtration Rate	3 to 36 months	This is an average for all participants during the 3-36 month study period
Carotid Artery Intima Thickness	6 to 36 months	Thickness of intima of right carotid artery; average of all particpants from 6-36 months of study
Endothelial Dysfunction	6 to 36 months	Post hyperemia increase in blood flow - fold increase from before and after occluding BP; values are mean of all participants in 6-36 months of study period.