National Meeting 2009

1049 — A Cost-Effectiveness Analysis of ACE-Inhibitors vs. Angiotensin Receptor Blockers for Treatment of Hypertension

Powers BJ (Durham VAMC Center for Health Services Research in Primary Care) , Datta SK (Durham VAMC Center for Health Services Research in Primary Care), Oddone EZ (Durham VAMC Center for Health Services Research in Primary Care)

Angiotensin Converting Enzyme Inhibitors (ACE-I) and Angiotensin Receptor Blockers (ARB) are equally effective for treating hypertension and preventing cardiovascular events, but differ greatly in cost. We compared the cost-effectiveness of the initial choice of an ARB versus an ACE-I for treatment of hypertension.

We used Markov modeling to conduct the cost-effectiveness analysis from the payer perspective. The model consisted of four health states: 1) start with ACE-I or ARB, 2) if intolerance develops switch to the other drug, 3) if intolerance develops with second drug stop all use, and 4) develops angioedema. Probabilities for developing intolerance to ACE-I and ARBs angioedema were based on systematic review of the literature. Costs were based on retail prices for drug costs and Medicare reimbursement for clinic visit to switch drugs and angioedema treatment. Effectiveness consisted of a value of one if the patient remained in the initial drug or switched to other drug health states and zero if they transitioned into the stop all ACE-I and ARB use or develops angioedema health states. The timeframe for the analysis was ten years, with both costs and effectiveness discounted at 3%.

The ACE-I initiated patient spent 8.05 of the 10 years taking an ACE-I or an ARB and incurred an expected cost of $6,271 ($6,061-$6,480); the ARB-initiated patient spent 8.33 of the 10 years taking an ARB or an ACE-I and incurred an expected cost of $2,434 ($2,310-$2,554, 95% CI). The incremental 0.28 years of gain cost an incremental $3,837 per patient. Treatment of patients with ARBs as first line would cost an additional $137,036 per patient to gain an additional 10 patient-years of persistence on an ACE-I or ARB. Sensitivity analyses did not identify any circumstances under which the base-case results changed.

Compared to ARB-initiated patients, ACE-I-initiated patients incur substantially lower treatment costs but only marginally higher intolerance and episodes of angioedema.

The restricted use of ARBs in the VA frees up significant resources. This information may be informative to the non-VA healthcare sector where the rate of initial use of ARBs is much higher.