A new Swiss study has found that overall, drug-eluting stents do not offer good value for money and this would still be the case if they were considerably cheaper. They are however, cost-effective when used to treat high-risk patients with particularly narrow arteries or who have stents fitted to bypass grafts.
These are the findings of Professor Matthias Pfisterer of the University Hospital in Basel, Switzerland, and colleagues and the study is published this week in The Lancet.
Drug eluting-stents are small tubes of mesh coated in drugs and designed to prop open clogged arteries and restore blood flow. The alternative is bare-metal stents which are thought to be more likely to collapse. However, drug-eluting stents have been controversial with some studies suggesting they can cause blood clots to form inside them.
Matthias and colleagues carried out an 18-month study on the cost-effectiveness of drug-eluting stents. This was part of the Basel Stent KostenEffekitvitäs Trial (BASKET), where 826 patients were fitted with either drug-eluting stents or bare-metal stents in the ratio of 2 to 1 respectively (545 to 281).
The study analysed the incremental cost effectiveness ratios (ICERs) of both the low risk and the high risk patients by weighing up the costs of the medical interventions against a measure of the benefits. To assess the benefits, researchers asked patients to fill in quality of life (EQ-5D) questionnaires from which they were able to work out patients’ quality-adjusted life years (QALYS), a combination of quality and length of life.
The low risk patients were the ones who were fitted with 3.0 mm or larger diameter stents in native blood vessels (i.e. vessels that were in their natural locations, as opposed to ones that had been grafted from another part of the body as in a bypass operation). The high risk patients were the ones with narrower arteries who needed stents smaller than 3.0 mm in diameter or they were patients who had stents fitted to bypass grafts.
The results showed that the overall costs for patients with drug-eluting stents were higher (11,808 Euros per patient, or about 17,000 dollars) than for patients fitted with bare-metal stents (10,450 Euros per patient, or about 15,000 dollars) which translated to an average greater cost per stent of 1,358 Euros (about 2,000 dollars).
The ICER cost of preventing a major adverse cardiac event for drug-eluting stents was 64,732 Euros (about 94,000 dollars) and the ICER cost per QALY gained was 40,467 Euros (about 58,000 dollars).
ICER cost was most affected by stent costs, number of events, and QALYS, but cost-effectiveness remained poor for the drug-eluting stents unless quite unrealistic figures were put in for these variables.
The researchers showed that the cost-effectiveness of drug-eluting stents was not viable by working out the probability of drug-eluting stents reaching an arbitrary ICER of 10,000 Euros or less to prevent one major cardiac event. This came out at 0.016 for low risk patients (i.e. very unlikely to be cost-effective) and 0.874 for high-risk patients (just about worth doing every time).
The authors concluded that:
“If used in all patients, drug-eluting stents are not good value for money, even if prices were substantially reduced. Drug-eluting stents are cost effective in patients needing small vessel or bypass graft stenting, but not in those who require large native vessel stenting.”
“Cost-effectiveness of drug-eluting stents in patients at high or low risk of major cardiac events in the Basel Stent KostenEffektivitäts Trial (BASKET): an 18-month analysis.”
Hans Peter Brunner-La Rocca, Christoph Kaiser, Alain Bernheim, Michael J Zellweger, Raban Jeger, Peter T Buser, Stefan Osswald, and Matthias Pfisterer.
The Lancet, Volume 370, Number 9598, 3 November 2007.
Written by: Catharine Paddock