Incorporating patient-centered outcomes in the analysis of cost-effectiveness: imaging strategies for renovascular hypertension.
OBJECTIVE
Our aim was to assess the contribution of patient-centered short-term disutilities and quality-of-life measures in the cost-effectiveness analysis of CT angiography, MR angiography, and conventional angiography in patients with medication-resistant hypertension.


METHODS
A decision analytic model compared the life expectancy and incremental cost per life year using three initial diagnostic tests in a cohort of hypothetical individuals with medication-resistant hypertension over a range of renal artery stenosis probabilities: CT angiography (sensitivity, 96%; specificity, 96%; cost, $865); MR angiography (98%, 94%, $850); and conventional angiography (99%, 99%, $2,627). All imaging strategies were compared with a base case scenario mimicking the natural history of medication-resistant hypertension and with a scenario immediate enhanced medical therapy without prior imaging. Individuals without evidence of renal artery stenosis on initial testing underwent conventional angiography if enhanced medical therapy failed to control hypertension. Individuals diagnosed with renal artery stenosis on MR angiography required conventional angiography for definitive stent treatment ($11,1223). Blood pressure response to renal artery stenting or enhanced medical therapy varied according to blood pressure, as did the incidence of myocardial infarction and stroke resulting from hypertension. Patients who progressed to end-stage renal disease received dialysis ($60,000 per year). Quality-of-life adjustments were made for patients with hypertension, end-stage renal disease, myocardial infarction, and stroke. Short-term disutilities from undergoing an imaging test were included. The analysis accounted for direct costs derived from Medicare reimbursements and total costs derived from the literature.


RESULTS
All imaging strategies were cost-effective compared with enhanced medical therapy alone or with natural history. When only direct costs were considered, MR angiography was the preferred strategy, with conventional angiography as a cost-effective alternative to MR angiography. When total costs were considered, conventional angiography dominated all other strategies. Adjusting for quality of life decreased the incremental cost-effectiveness ratios, making an already competitive strategy a more favorable alternative to the base case. Adjusting for test-related disutility did not significantly influence the cost-effectiveness of any of the imaging tests. Despite marked variation in the key clinical and cost variables, MR angiography remained the most cost-effective strategy.


CONCLUSIONS
In the evaluation and treatment of medication-resistant hypertension, strategies that included preliminary imaging saved more lives than did the immediate institution of enhanced medical therapy at a lesser cost.
Carlos
Ruth C
RC
Department of Radiology, University of Michigan, 1500 E Medical Center Dr., Ann Arbor, MI 48109-0030, USA.
Axelrod
David A
DA
Ellis
James H
JH
Abrahamse
Paul H
PH
Fendrick
A Mark
AM
D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D006801:Humans; D006978:Hypertension, Renovascular / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D018810:Magnetic Resonance Angiography / Q000191:economics*; D018802:Patient-Centered Care / Q000191:economics*; D019057:Quality-Adjusted Life Years; D012680:Sensitivity and Specificity; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000191:economics*; D016896:Treatment Outcome