VA NEPHRON-D: Diabetes iN Nephropathy Study

Overview

Diabetes is the leading cause of end-stage renal disease (ESRD) in the United States. The overall rate of ESRD secondary to diabetes has risen 68% since 1992. Medications that block the renin angiotensin system have been shown to decrease the progression of diabetic nephropathy. The use of an angiotensin receptor blocker (ARB) has been shown to decrease the risk of progression of kidney disease in two studies of individuals with Type 2 diabetes and proteinuria. Despite the use of an ARB, the incidence of renal failure remained high in the treated group in both studies. The combination of an angiotensin converting enzyme inhibitor (ACEI) and ARB can lead to more complete blockade of the renin angiotensin system. In diabetic kidney disease, combination therapy has been shown to decrease proteinuria in short-term studies. Although there are encouraging results for improvement in proteinuria there are no data on progression of kidney disease for the use of combination of ACEI and ARB therapy in patients with diabetes. In addition, there could be an increased risk of serious hyperkalemia in individuals with diabetes who receive combination ACEI and ARB. The investigators therefore propose a randomized double blind multi-center clinical trial to assess the effect of combination of ACEI and ARB in patients with diabetes and proteinuria on progression of kidney disease.

Primary Hypothesis: To evaluate the combination of an angiotensin converting enzyme inhibitor (ACEI) with an angiotensin receptor blocker (ARB) vs. standard treatment with angiotensin receptor blocker on the progression of kidney disease in individuals with Type 2 diabetes and overt nephropathy. The primary outcome is a composite endpoint of reduction in estimated GFR of 30 ml/min/1.73m\*m in individuals with an estimated baseline GFR greater than or equal to 60 ml/min/1.73m\*m; reduction in estimated GFR of greater than 50% in individuals with an estimated baseline GFR less than 60 mL/min/1.73m\*m; progression to end-stage renal disease (defined as need for dialysis, renal transplant or an eGFR less than 15 ml/min/1.73m\*m) or death. Secondary outcome: a renal composite endpoint, defined as; reduction in estimated GFR of more than 50% (for individuals with a baseline estimated GFR less than 60 ml/min/1.73m\*m); reduction in estimated GFR of more than 30 ml/min/1.73m\*m (for individuals with a baseline estimated GFR greater than or equal to 60 ml/min/1.73m\*m) or progression to end-stage renal disease (defined as need for dialysis, renal transplant or an eGFR of less than 15 ml/min/1.73m\*m). Tertiary outcomes are cardiovascular events (cardiovascular mortality, myocardial infarction, cerebrovascular accident, admission for heart failure), change in albuminuria at 12 months and decline in slope of kidney function. Study Abstract: The study is a multi-center, prospective, randomized, parallel group trial to test the efficacy of the combination of an angiotensin converting enzyme inhibitor (ACEI) with an angiotension receptor blocker (ARB) vs. standard treatment with angiotension receptor blocker on the combined end-point. The primary outcome is a composite endpoint of reduction in estimated GFR of 30 ml/min/1.73m\*m in individuals with an estimated GFR greater than or equal to 60 ml/min/1.73m\*m; reduction in estimated GFR of greater than 50% in individuals with an estimated GFR less than 60 ml/min/1.73m\*m; progression to end-stage renal disease (defined as need for dialysis, renal transplant or en eGFR less than 15 ml/min/1.73m\*m)or death. The study population is individuals with type 2 diabetes and overt nephropathy. Eligible subjects who consent to participate will be randomized into either the combination therapy arm or the mono therapy arm. The randomization will be stratified by site and within sites by baseline albuminuria (\< 1 vs. greater than or equal to 1 gram/gram creatinine) and eGFR (\< 60 vs. greater than or equal to 60 ml/min/1.73m\*m). All participants will receive open label therapy with losartan, an ARB, as standard of care. Patients not treated with an ACEI or ARB will be initiated on losartan; patients treated with an ACEI or ARB other than losartan (the study ARB) will be converted to losartan (the study ARB) and the dose titrated to 100 mg/day. Individuals who tolerate ARB 100mg/day criteria will be randomized in a 1:1 ratio to the addition of blinded lisinopril (the study ACEI) or placebo. The medication (lisinopril or placebo) will be titrated from an initial dose of 10 mg/day to a target dose of 40 mg/day. After each adjustment in dose, serum chemistries will be evaluated for kidney function and potassium levels. Subjects will be enrolled over a period of 4.25 years and the maximum length of follow-up is 6.25 years. The planned study duration is 6.25 years with 4.25 years of accrual and 6.25 years of follow-up for all enrolled patients. The intervention was stopped on November 7, 2012 for safety concerns after an interim analysis. Patients are still under passively follow-up without intervention.