Systematic review, meta-analysis and economic modelling of ...

Assessment of cost-effectiveness evidenceExpected value of perfect informationThe individual patient EVPI for the prognostic model is illustrated in Figure 43. At low and high thresholdsfor cost-effectiveness, additional information is unlikely to change that decision. The EVPI reachesmaximum when there is most uncertainty about whether to adopt or reject the technology based onexisting evidence, i.e. at a threshold of £19,000/QALY.The EVPI for the whole population can be estimated as ‘EVPI per patient multiplied by the number ofpatients affected by the decision over the lifetime of the technology’. Assuming an incidence of 1000patients of the disease per year and a lifetime of 10 years for the technology, the undiscounted populationEVPI at the threshold of £19,000/QALY is £1.09M.Expected value of partial perfect informationThe expected value of partial perfect information (EVPPI) details associated with the parameters areillustrated in Figures 44 and 45. At the threshold of £20,000/QALY, EVPPIs associated with baseline risk ofMI and relative reduction in risk of adverse events after treatment are higher than the EVPPIs associatedwith the rest of the parameters. However, at the threshold of £30,000/QALY, only the EVPPI associatedwith relative reduction in risk of adverse events is significant.Around the NICE threshold, assumed to be between £20,000 and £30,000/QALY, the EVPPIs associatedwith both these parameters are relatively high suggesting that further experimental research will potentiallybe cost-effective.120100EVPI per patient8060402000 50 100Threshold (£000)150 200 250FIGURE 43 Individual patient EVPI.104NIHR Journals Library