A comparison of total hospital costs for percutaneous coronary intervention patients receiving abciximab versus tirofiban

Evaluating the Generalisability of Trial Results: Introducing a Centre- and Trial-Level Generalisability Index

BACKGROUND

Few randomised controlled trials (RCTs) recruit centres representatively, which may limit the external validity of trial results.

OBJECTIVE

The aim of this study was to propose a proof-of-concept method of assessing the generalisability of the clinical and cost-effectiveness findings of a given RCT.

METHODS

We developed a generalisability index (Gix), informed by centre-level characteristics, as a measure of centre and trial representativeness. The centre-level Gix quantifies how representative a centre is in relation to its jurisdiction, e.g. a country or health authority. The trial-level Gix quantifies how representative trial recruitment is in relation to clinical practice in the jurisdiction. Taking a real-world RCT as a case study and assuming trial-wide results to represent 'true jurisdiction values', we used simulation methods to recreate 5000 RCTs and investigate the relationship between trial representativeness, reflected by the standardised trial-Gix, and the deviation of simulated trial results from the 'true values'.

RESULTS

The simulation study provides evidence that trial results (odds ratio for the primary outcome and incremental quality-adjusted life-years) were influenced by the representativeness of the sample of recruiting centres. Simulated RCTs with the closest results to the 'true values' were those whose recruitment closely mirrored the jurisdiction-wide context. Results appeared robust to six alternative specifications of the Gix.

CONCLUSIONS

Our findings suggest that an unrepresentative selection of centres limits the external validity of trial results. The Gix may be a valuable tool to help facilitate rational selection of trial centres and ensure the generalisability of results at the jurisdiction level.

The Role of Risk Stratification in the Decision to Provide Upstream Versus Selective Glycoprotein IIb/IIIa Inhibitors for Acute Coronary Syndromes

OBJECTIVES

We endeavored to determine under what conditions a strategy of upstream use of small molecule platelet glycoprotein (GP) IIb/IIIa inhibitors for all acute coronary syndromes (ACS) patients is cost effective compared to that of selective use of abciximab in only those patients requiring percutaneous coronary intervention (PCI).

BACKGROUND

Small molecule GP IIb/IIIa inhibitors have shown benefit in ACS, but abciximab, the more expensive GP IIb/IIIa inhibitor, may be more effective during PCI. However, abciximab does not have proven efficacy in medical management. No prior study has attempted to balance these competing benefits.

METHODS

A decision analysis was performed to examine two strategies: 1) treat all ACS patients upstream with a small molecule GP IIb/IIIa inhibitor and continue through medical management and PCI, if performed; or 2) wait, and selectively use abciximab only in patients who ultimately undergo PCI. Applicable randomized controlled trial data were used for the principal analysis.

RESULTS

The strategy of upstream use of a small molecule GP IIb/IIIa inhibitor was superior to selective use, and economically acceptable, with a cost-effectiveness ratio of 18,000 dollars per year of life gained. The superiority of the upstream use strategy persisted over the majority of sensitivity analyses. When stratified by risk according to Thrombolysis in Myocardial Infarction risk score, a strategy of upstream use was only cost effective in those patients with moderate or high risk.

CONCLUSIONS

Upstream use of small molecule GP IIb/IIIa inhibition in ACS patients with moderate or high risk for cardiovascular events is a cost-effective approach that should be considered in this subset of patients.

Choice of GPIIb/IIIa antagonist in percutaneous coronary intervention: how should economic criteria be factored in?

OBJECTIVE

Three GPIIb/IIIa antagonists are available in the market. In France, as in many countries, their acquisition costs strongly differ. The objective of this study was to analyze how economic criteria-beyond the acquisition cost-should be factored in, when choosing a GPIIb/IIIa antagonist.

METHOD

Both clinical and economic papers on the use of GPIIb/IIIa antagonists in percutaneous coronary interventions published in peer-review journals from 1994 to 2002 were reviewed and analyzed.

RESULTS

Cost differentials between products strongly vary from one 'cost concept' to another, i.e., acquisition cost, administration cost, hospital cost, net treatment cost. The comparison of efficacy is even more complicated, as most of the time only indirect comparisons are available, based on different clinical studies, with different durations and definitions of outcomes. Finally, cost-effectiveness ratios range from US dollar 10,695 per avoided event for eptifibatide (IMPACT II study) to US dollar 74,047 for tirofiban (RESTORE study).

CONCLUSION

The concept of cost, inevitably entering into the choice of a medicinal strategy, must be used with caution. The amplitude of the difference between products, and the product favored by the difference, vary according to the cost concept retained.