Do economic evaluations have a role in decision-making in Medicine Management Committees? A qualitative study

Abstract

Objective

To explore pharmacists’ perceptions on the use of economic evaluations in decision-making within Medicine Management Committees (MMCs), identify factors that influence the uptake of economic evidence and examine the usefulness of different presentations of economic evidence.

Method

This two-stage qualitative study was carried out in July and August 2004 in two hospitals in northwest England. First, a researcher observed the decision-making process at two MMCs. Handwritten notes were made during observation, which were later transcribed. Subsequently, in-depth semi-structured interviews were conducted with a purposive sample of pharmacists involved in the MMCs. The interviews explored pharmacists’ views on the usefulness of economic evaluations in decision-making, the factors influencing the uptake of economic evidence by the MMCs, and the optimal presentation of economic results. The interviews were audiotaped and transcribed verbatim. All the transcribed data were thematically analysed using the constant comparison approach.

Results

In all, six new drug applications were observed and ten pharmacists were interviewed. Pharmacists were observed to play an important role in decisions about drug formularies in hospitals. Although interviewees considered that timely economic evaluations would be useful in reviewing new medicines, the actual use of economic evidence in decision-making within MMCs was limited. The barriers to using economic evaluations included pharmacists’ lack of initiative to search for and difficulty in understanding economic evaluations, and the perceived availability, credibility and transferability of economic studies. However, the main barrier to implementing economic evidence was the decision makers’ concern about the impact of the medicines on the hospitals’ drug budgets. Interviewees felt that they understood and trusted disaggregated economic results better than aggregated ones.

Conclusion

This study found the use of economic evidence in decision-making at both MMCs was limited. To improve the usefulness of economic evaluations in MMCs, members of MMCs will need more training in accessing, understanding and appraising economic evidence; researchers need to improve the credibility and transferability of economic studies, and present the results in clear and understandable ways. However, due to the restricted focus of local, short-term drug budgets, evidence-based decision-making remains a challenge for local MMCs.

Appendix 1 The five-level outcome presentation of a cost-effectiveness analysis

 

At this stage of interview, the principal researcher briefly explained the hypothetical scenarios of a cost-effectiveness analysis to individual participants using the above framework.

Point estimate

 

This table shows that compared to ketorolac, parecoxib cost £31,359 less to treat 1,000 patients, and resulted in 3 fewer patients having GI bleeding.

Point estimate with 2.5th and 97.5th percentile

 

Compared to ketorolac, parecoxib causes 1–5 fewer patients to have GI bleeding, and costs in a range from £72,964 less to £8,286 more to treat 1,000 patients.

Incremental cost-effectiveness ratio

 

The incremental cost effectiveness ratio (ICER) is the cost of achieving an extra unit of outcome, i.e. the cost per GI bleeding averted. The ICER was calculated as:

$$ {\hbox{ICER}}\, = \,\frac{{\Delta \,{\hbox{cost}}}} {{\Delta \,{\hbox{effectiveness}}}}\, = \,\frac{{ - \pounds{\hbox{30,937}}}} {3}\, = \, - \pounds{\hbox{10,312}} $$

Where ‘Δ costs’ refers to the difference in costs between the two alternatives, and ‘Δ effectiveness’ is the difference in effectiveness between the two alternatives.¹

Cost-effectiveness plane

 

Compared parecoxib against ketorolac, if the ICERs fall in the four quadrants (see the following figure) of cost-effectiveness plane indicates parecoxib is: (I) more expensive, more effective; (II) more expensive, less effective; (III) less expensive, less effective; and (IV) less expensive, more effective.

The cost-effectiveness of parecoxib not only depends on the uncertainty in the estimated values of cost and outcome, but also a decision maker’s willingness-to-pay for preventing one gastrointestinal bleed. The decision maker’s maximum willingness-to-pay can be presented as the slope (λ) of a price line on the cost-effectiveness plane. If the ICERs are less than λ, i.e. the dots lie below the price line, then it shows that parecoxib is cost-effective.

Cost-effectiveness acceptability curve

 

The cost-effectiveness acceptability curve is an estimate of the proportion of the sampling distribution of costs and effects that lie below the price line (willingness to pay for each GI bleeding avoided) in the cost-effectiveness plane. This figure shows there is 66% probability that parecoxib is cost-effective even if the decision-maker is not willing to pay anything for preventing one extra GI bleeding. There is 95% probability that parecoxib is cost-effective when a decision maker is willing to pay up to £23,100 to avoid one extra GI bleeding.