Objectives: We performed a cost-consequence analysis in a French setting of the renoprotective benefit of irbesartan in hypertensive type 2 diabetes patients over a 25-year period.
Research design and methods: A previously published Markov model simulated progression from microalbuminuria to overt nephropathy, doubling of serum creatinine, end-stage renal disease and death. Three treatment strategies with analogous blood pressure control were compared: (A) control--conventionally medicated antihypertensive therapy (excluding angiotensin converting enzyme inhibitors, other angiotensin-2-receptor antagonists and dihydropyridine calcium channel blockers) initiated at microalbuminuria; (B) early irbesartan--(300 mg daily added to control, initiated with microalbuminuria) and (C) late irbesartan--(300 mg daily, initiated with overt nephropathy). Probabilities came from the Irbesartan in Reduction of Microalbuminuria-2 study, Irbesartan in Diabetic Nephropathy Trial and other sources. Clinical and economic outcomes were projected over 25 years. Annual discount rates were 3%.
Results: Compared to control, early use of irbesartan added (mean +/- standard deviation) 1.51 +/- 0.08 undiscounted life years (discounted: 0.94 +/- 0.05 years), while late irbesartan added 0.07 +/- 0.01 (0.04 +/- 0.01) years/patient. Early irbesartan added 1.03 +/- 0.06 discounted quality-adjusted life years (QALYs), while late irbesartan added 0.06 +/- 0.01 QALYs. Early and late irbesartan treatments were projected to save 22,314 +/- 1273 euro and 6619 +/- 820 euro/patient, respectively versus control. Sensitivity analysis showed that even over short time horizons both irbesartan treatments were superior to the control group.
Conclusions: In France, early irbesartan treatment improved quality and length of life and reduced costs in hypertensive patients with type 2 diabetes and microalbuminuria. Late irbesartan therapy is beneficial, but earlier irbesartan leads to better outcomes.