Model Shows Cost-Effectiveness of Renal Denervation in Men, Women

Renal denervation is a cost-effective therapy for patients with refractory hypertension up to about age 80, according to a study published online October 22, 2012, ahead of print in the European Heart Journal. The data add to growing evidence that the investigational catheter-based radiofrequency ablation treatment is a valid option for patients with true refractory hypertension.

Marc Dorenkamp, MD, of Charité-Universitätsmedizin Berlin (Berlin, Germany), and colleagues constructed a Markov state-transition model to determine the benefits, costs, and cost-effectiveness of renal denervation in patients with resistant hypertension. The model incorporated German and North European registry data on the probability of cardiovascular disease mortality.

Both Sexes Benefit

Compared with best medical therapy alone, which was assumed to be a regimen of metoprolol, ramipril, and torasemid at maximum doses, renal denervation was associated with increased health care costs in each age group. However, it resulted in a gain of 0.98 quality-adjusted life-years (QALYs) in men and 0.88 QALYs in women 60 years of age. The additional costs per year compared with best medical therapy alone were approximately $3,353 (€2,589) for men and $2,647 (€2,044) for women.

Assuming a willingness-to-pay threshold of $45,335 (€35,000) per QALY, there was a 95% probability that renal denervation would remain cost-effective up to age 78 in men and age 76 in women. At higher thresholds, the procedure would likely be cost-effective even at advanced ages. At ages 80 years and older, however, cost-effectiveness became more favorable in men than in women.

The factors that most influenced cost-effectiveness were:

• Magnitude of effect of renal denervation on systolic blood pressure
• Rate of nonresponders
• Procedure costs

Results Make ‘Reasonable Sense’

According to the study authors, previously published models have mainly based the risk estimation for cardiovascular disease events on Framingham risk equations, while their model incorporates observed incidence rates and adjusts the rates according to systolic blood pressure levels. “This approach avoids potential bias introduced by using risk equations and by uncertainties due to distances in geography and time,” they write.

David J. Cohen, MD, MSc, of Saint Luke’s Mid America Heart Institute (Kansas City, MO), told TCTMD in a telephone interview that the model is “interesting and intuitive” and differs from a recent analysis (Geisler BP, et al. J Am Coll Cardiol. 2012;60:1271-1277) in that it offers a European view and focuses more directly on age and sex.

“The results make reasonable sense,” Dr. Cohen said. “Patients who are treated at older ages are going to stand to derive a lot less benefit because they have fewer years to derive that benefit.

“But this analysis has an enormous [number] of assumptions, very few of which are subject to testing,” he continued. “I would say the biggest limitation is that the treatment [effect] is durable for life. The longest-term data I’ve seen are only 2 or 3 years. So, you can’t take at face value the assumption that this is going to be durable [for decades] of someone’s life. I would have liked to see them do sensitivity analyses on the duration of benefit.”

Age a Consideration, Not a Cutoff

In a telephone interview with TCTMD, Ajay J. Kirtane, MD, SM, of Columbia University Medical Center (New York, NY), stressed that the age cutoffs should not be overinterpreted.

“It’s still going to be effective in this patient population, it’s just that the cost-effectiveness threshold goes up. We should not discriminate on the basis of age,” he said.

Dr. Kirtane said studies such as this are important from the perspective of budgeting and anticipating costs once the therapy becomes available in the United States.

Although renal denervation is currently available in Europe and parts of Asia, a decision on approval by the US Food and Drug Administration awaits completion of the ongoing randomized Symplicity HTN-3 trial, comparing the procedure using the Symplicity catheter system (Medtronic, Minneapolis, MN) with medical therapy alone.

“I think the FDA wants to be absolutely sure that this therapy is as effective as [Symplicity HTN1 and Symplicity HTN-2] have shown and additionally that it is safe to be used in a more widespread fashion,” Dr. Kirtane added.

“You can argue that even without crunching a number, these are patients who are maximally treated and there is nothing else you can do for them but offer this treatment,” he said, adding that overall the procedure is relatively simple and likely will be available in an outpatient setting.

Dr. Cohen cautioned, however, that renal denervation should be limited to patients who fit a strict profile of true resistant hypertension, since many patients thought to be resistant are in fact simply noncompliant.

“Studies like this are helpful in demonstrating that within reason and for these carefully selected patients, this treatment is going to be cost-effective,” he said. “It’s an important message for payers because they experience the upfront cost of the therapy. In the United States, people change insurance plans frequently, so many times payers don’t have incentives to provide treatments where they pay the [upfront procedural] cost and then some other payer 3, 5, or 10 years down the line reaps the benefits. This type of analysis helps to demonstrate that for the right population, this is something we should be paying for, even if the benefits do not occur immediately.”

Dorenkamp M, Bonaventura K, Leber AW, et al. Potential lifetime cost-effectiveness of catheter-based renal sympathetic denervation in patients with resistant hypertension. Eur Heart J. 2012;Epub ahead of print.

Related Stories:

• Model Suggests Renal Denervation Cost-effective for Resistant Hypertension
• Symplicity Works: Renal Denervation Reduces Resistant Hypertension
• Renal Denervation Shows Promise for Heart Failure, Ongoing Success Against Hypertension