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

Assessment of cost-effectiveness evidenceTABLE 58 Cost-effectiveness of strategies for (n = 1000) troponin-negative patients, using data from Mills 155Strategy Total costs (£) Total QALYs ICER (£/QALY)No testing 374,040 11,891.14 –Exercise ECG 678,120 11,917.75 Extendedly dominatedH-FABP 544,340 11,911.26 8464CTCA 937,426 11,946.86 11,041ICA 1,705,790 11,950.36 219,532TABLE 59 Cost-effectiveness of strategies for troponin-negative patients, using data from the RATPAC trial 12Strategy Total costs (£) Total QALYs ICER (£/QALY)No testing 260,901 12,180.71 –Exercise ECG 590,601 12,181.78 DominatedH-FABP 449,520 12,182.57 101,408CTCA 876,680 12,184.20 262,061ICA 1,656,701 12,176.07 DominatedThe cost-effectiveness of CTCA therefore appears to depend on the assumed rate of subsequent deathand non-fatal MI. Given the uncertainty in these risks, we performed ‘goal-seeking’ analysis to identify thelevel of risk at which the ICER for CTCA crosses the NICE threshold of £20,000–30,000/QALY comparedwith either H-FABP, ETT or no testing. We assumed a proportional relationship that risk of non-fatal MIis four times the risk of death. The results are shown in Table 60. Depending on the threshold used,CTCA is likely to be cost-effective if the combined risk of death and non-fatal MI within the time periodassumed to be influenced by initial diagnostic testing exceeds 2% (£30,000/QALY threshold) or 2.9%(£20,000/QALY threshold).Probabilistic results of the prognostic modelThe main probabilistic analysis for the prognostic model, using the 1-year event rates from Mills, 155is shown in Figure 41. CTCA had the highest probability of being cost-effective at thresholds above£10,000/QALY. Around £10,000 H-FABP had the highest probability, and below this level no testing hadthe highest probability of being cost-effective.The main probabilistic analysis for the prognostic model, using the 1-year event rates from RATPAC, 12 isshown in Figure 42. No testing was highly likely to be the most cost-effective strategy for all thresholdsof < £100,000/QALY.Value of information analysesThere is always a chance that the wrong decision will be made as a result of the uncertainty in the existinginformation and the costs in terms of health benefit and resources forgone owing to this uncertainty canbe interpreted as expected value of perfect information (EVPI). Perfect information would eliminate thepossibility of making the wrong decision and therefore EVPI is determined jointly by the probability that adecision based on existing information will be wrong and the consequences of a wrong decision.The EVPI, although calculated for individual patients, can also be expressed for the total population ofpatients who stand to benefit, based on prevalence and the lifetime of the technology. This can also bethought as the maximum that the health-care system should be willing to pay for additional evidence toinform the decision in the future and thus is an upper bound on the value of conducting further research,102NIHR Journals Library