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The drug is cost-effective, should be initiated early, and continued long
term in diabetic patients with hypertensive kidney disease.
Reviewed by Andrew J. Palmer, BSC, MBBS
“This study identified the most efficient time point at which [ARB] treatment with irbesartan for renal disease associated with type 2 diabetes and hypertension should be initiated,” said Andrew J. Palmer, BSc, MBBS, from the CORE-Center for Outcomes Research in Basel, Switzerland. “The study demonstrated the importance of early treatment of patients with type 2 diabetes, hypertension and microalbuminuria,” Dr. Palmer and colleagues reported results in Diabetes Care.
The investigators used a Markov model to simulate progression from microalbuminuria to overt nephropathy, doubling of serum creatinine, end-stage renal disease (ERSD), and death in hypertensive patients with type 2 diabetes. They created two irbesartan treatment strategies: early irbesartan 300 mg daily and late irbesartan 300 mg daily initiated with overt nephropathy. They compared the strategies with control which consisted of antihypertensive treatment with standard therapy — excluding ACE inhibitors, other ARBs and dihydropyridine calcium-channel antagonists.
COMPARABLE BLOOD PRESSURE MAINTENENCE
The control group had comparable blood pressure maintenance initiated at microalbuminuria. The Irbesartan in Type 2 Diabetes with Microalbuminuria-2 (IRMA-2) Study, the Irbesartan in Diabetic Nephropathy Trial (IDNT) and other published sources were used to calculate transition probabilities, Dr. Palmer said.
The researchers evaluated 1,000 simulated patients, projecting costs and life expectancy over 25 years in a typical American third-party payer system, discounted at 3% yearly. Early and late irbesartan treatment in 1,000 patients were projected to save $11.9 ±3.3 million and $3.3 ±2.7 million, respectively.
The early strategy added 1,550 undiscounted life-years in 1,000 patients compared to 71 undiscounted life-years for the late strategy, Dr. Palmer and colleagues said.
“Treating these patients with irbesartan when they first develop microalbuminuria was projected to extend life and reduce costs,” Dr. Palmer wrote. “Late use of irbesartan is also better and less costly than standard care, but irbesartan should be started earlier and continued long term to maximize the impact on ESRD, reduction in mortality and cost savings.”
The researchers said they were encouraged by the fact that the results were robust under a wise range of plausible assumptions.
“We need to address the issue of which ARB is best, and the issue of ARB's versus ACE inhibitors,” Dr. Palmer said in an interview. “Additionally, further research should address other populations (type 1 diabetes, nondiabetic patients), and should treatment start even before the development of microalbuminuria.
Physicians need to be aware that diabetes patients must be regularly screened for microvascular complications, and that appropriate treatment may lead to substantial improvements in patients' long-term outcomes, Dr. Palmer said. n
Andrew J. Palmer, BSc, MBBS, is with CORE-Center for Outcomes Research in Basel, Switzerland. He can be reached at 41 (0) 61 383 0756 or ap@thecenter.ch. CORE, Dr. Palmer’s company, has received unrestricted research grants and consultation fees from Sanofi-Synthelabo Inc. (New York) and Bristol-Myers Squibb Company (New York).
1. Palmer AJ, Annemans L, Roze S, et al. Cost-effectiveness of early irbesartan treatment versus control or late irbesartan treatment in patients with type 2 diabetes, hypertension, and renal disease. Diabetes Care. 2004;27:1897-1903.
2. Parving HH, Lehnert H, Brochner-Mortensen J, et al. The effect of irbesartan on the development of diabetic nephropathy in patients with type 2 diabetes. N Engl J Med. 2001;345:870-878.
3. Lewis EJ, Hunsicker LG, Clarke WR, et al. Renoprotective effect of the angiotensin-receptor antagonist irbesartan in patients with nephropathy due to type 2 diabetes. N Engl J Med. 2001;345:851-860.
