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

DOI: 10.3310/hta17010 Health Technology Assessment 2013 Vol. 17 No. 1The cost of reinfarction was estimated as a one-off cost of £3587 from NHS reference costs. 161 The costsare outlined in Tables 56 and 57.Modelling methodologyA model was developed using DecisionPro (Vanguard Software Corporation, Cary, NC, USA) to explore thecosts and health outcomes associated with different prognostic strategies. The analysis was conducted fortroponin-negative patients aged 40–75 years after initial hospital assessment. The model takes a lifetimehorizon with mean life expectancy based on UK interim lifetables. 158 The economic perspective of themodel is the NHS in England and Wales.Deterministic results of the prognostic modelThe main deterministic analysis for the prognostic model, using the 1-year event rates from Mills, 155 isshown in Table 58. The total costs increase in proportion to the cost of the test involved and the QALYsin proportion to the prognostic value of the test. Although we assumed ICA had perfect prognostic valueit incurred a significant QALY loss due to procedure-related adverse events. Exercise ECG was subjectto extended domination. H-FABP and CTCA would both be considered cost-effective compared withthe NICE threshold of £20,000–30,000/QALY. CTCA is the more effective of these two strategies andwould therefore be considered optimal. Although ICA is slightly more effective than CTCA, the ICER of£219,532/QALY substantially exceeds the usual NICE threshold for decision-making.The analysis was repeated using 3-month event rates from the RATPAC trial 12 and the implicit assumptionthat events were only influenced by testing up to 3 months. The results are shown in Table 59. Changingthe assumed baseline rate of adverse events and the time horizon over which initial diagnostic testingcould influence event rates markedly reduced the estimated QALY gains from diagnostic testing strategiescompared with no testing. ICA even appeared to be less effective than no testing, presumably becausethe negative effect of procedure-related events outweighed the benefit of reducing subsequent adverseoutcome in a low risk population. Although the other strategies gained a small number of QALYscompared with no testing, exercise ECG was dominated by H-FABP and both H-FABP and CTCA accruedQALYs at with a very high ICER. Therefore, assuming the adverse event rate from the RATPAC trial, 12 theno-testing strategy appeared to be optimal.TABLE 56 Cost estimates used in the modelDiagnostic test Source Estimate (£) 95% CI (£)CTCA NHS Reference Costs 161 109 90 to 206Exercise ECG Mowatt 25 69 66 to 107H-FABP RATPAC 160 20 18 to 22ICA Mowatt 25 1032 850 to 1100TABLE 57 Lifetime costs of patients with MIAge (years) MI cost (£)30–44 4012.545–54 311555–64 221565–74 1530> 75 800© Queen’s Printer and Controller of HMSO 2013. This work was produced by Goodacre et al. under the terms of a commissioning contract issued by the Secretary of Statefor Health. This issue may be freely reproduced for the purposes of private research and study and extracts (or indeed, the full report) may be included in professional journalsprovided that suitable acknowledgement is made and the reproduction is not associated with any form of advertising. Applications for commercial reproduction should beaddressed to: NIHR Journals Library, National Institute for Health Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton SciencePark, Southampton SO16 7NS, UK.101