Objective: The aim of this study was to determine the most cost-effective time point for initiation of irbesartan treatment in hypertensive patients with type 2 diabetes and renal disease.
Research design and methods: This study was a Markov model-simulated progression from microalbuminuria to overt nephropathy, doubling of serum creatinine, end-stage renal disease, and death in hypertensive patients with type 2 diabetes. Two irbesartan strategies were created: early irbesartan 300 mg daily (initiated with microalbuminuria) and late irbesartan (initiated with overt nephropathy). These strategies were compared with control, which consisted of antihypertensive therapy with standard medications (excluding ACE inhibitors, other angiotensin-2 receptor antagonists, and dihydropyridine calcium channel blockers) with comparable blood pressure control, initiated at microalbuminuria. Transition probabilities were taken from the Irbesartan in Reduction of Microalbuminuria-2 study, Irbesartan in Diabetic Nephropathy Trial, and other published sources. Costs and life expectancy, discounted at 3% yearly, were projected over 25 years for 1,000 simulated patients using a third-party payer perspective in a U.S. setting.
Results: Compared with control, early and late irbesartan treatment in 1,000 patients were projected to save (mean +/- SD) 11.9 +/- 3.3 million dollars and 3.3 +/- 2.7 million dollars, respectively. Early use of irbesartan added 1,550 +/- 270 undiscounted life-years (discounted 960 +/- 180), whereas late irbesartan added 71 +/- 40 life-years (discounted 48 +/- 27) in 1,000 patients. Early irbesartan treatment was superior under a wide-range of plausible assumptions.
Conclusions: Early irbesartan treatment was projected to improve life expectancy and reduce costs in hypertensive patients with type 2 diabetes and microalbuminuria. Later use of irbesartan in overt nephropathy is also superior to standard care, but irbesartan should be started earlier and continued long term.