Abstract
OBJECTIVE: To estimate 8-year health and economic outcomes of the angiotensin II receptor blocker valsartan versus the calcium channel blocker amlodipine in therapy of patients with type 2 diabetes and microalbuminuria based on clinical endpoints from a 6-month randomized controlled clinical trial, the MicroAlbuminuria Reduction With VALsartan (MARVAL) study. METHODS: We developed a Markov model that utilized urinary albumin excretion rate data to project patient distributions to 7 possible health states over 8 years. For each health state, we identified quality-adjustment weights (health utilities) and medical care costs from public sources. The model then calculated mean quality-adjusted survival, medical care costs, and cost-effectiveness ratios for each treatment arm. Treatment arms were compared with the incremental cost-effectiveness ratio. RESULTS: Patients treated with valsartan gained 7 months (mean) per patient of quality-adjusted survival relative to patients treated with amlodipine (77 versus 70 months; P<0.01); valsartan patients also incurred 32,412 dollars (mean) per patient lower medical costs than amlodipine patients (92,058 dollars versus 124,470 dollars; P<0.01). Model results were consistent for each year of analysis and robust to changes in key model parameters. CONCLUSION: This research (1) extends 6-month clinical trial outcomes to an 8-year period, (2) translates health outcomes from technical clinical endpoints to quality-adjusted survival, and (3) estimates economic consequences of therapeutic outcomes. The results quantify the favorable long-term health (i.e., quality-adjusted survival) and economic benefits (i.e., lower total medical costs) of therapy with valsartan, an angiotensin II receptor blocker, versus amlodipine, a calcium channel blocker, in the treatment of patients with type 2 diabetes and microalbuminuria based on an extension of the results of a short-term clinical (MARVAL) trial. These research findings are important to the extent patients with type 2 diabetes and microalbuminuria do not receive the recommended antihypertensive agents that block the renin-angiotensin system (angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers).