138 Chapter 8 Results Basic model Comparing average one year health benefits, DSA was the most effective diagnostic option, yielding 0.6039 QALYs (SD 0.0148), followed by CTA yielding 0.5983 QALYs (SD 0.0146) and MRA yielding 0.5947 QALYs (SD 0.0146). The total one year health costs were lowest for DSA (€39,808; SD €1,384), followed by CTA (€40,748; SD €1,510) and MRA (€41,814; SD €1,644). Initial diagnostic costs were highest for DSA while therapy and health state related costs were lowest for DSA, resulting in an overall less costly management. CTA as diagnostic test resulted in 128 out of 1,000 patients being referred for clipping although coiling would have been feasible. With MRA, 187 patients out of 1,000 were treated surgically although endovascular treatment would have been feasible. DSA was both more effective and less costly over one year and dominated CTA and MRA. CTA was more effective and less costly and thus dominated MRA. Table 2 shows costs and QALYs for the three diagnostic tests. Table 2. Related one-year costs and QALYs for MRA, CTA and DSA per patient in the basic model MRA CTA DSA Costs (€) QALYs Costs (€) QALYs Costs (€) QALYs MRA resp. CTA 252 0,5947 197 0,5983 0,6039 DSA *168 *214 725 Total diagnostic 420 411 725 Treatment 26.734 26.119 25.552 Death 217 213 205 Disability costs 14.443 14.005 13.324 Total 41.814 0,5947 40.748 0,5983 39.808 0,6039 * average costs per patient for DSA performed in case CTA / MRA showing no aneurysm Scenario model The strategy that included DSA for every patient for whom coiling was not deemed feasible on the basis of CTA and MRA, led to equal effectiveness for DSA, MRA and CTA (0,6039 QALYs each). In this approach no patient was treated surgically unless coiling was no option. In this scenario, CTA was less costly reaching a total average one year’s cost per patient of €39,767, and therefore cost-effective compared to MRA and DSA which reached costs of €39,851 and €39,808 respectively. Table 3 shows total one year’s costs and QALYs as well as incremental costs and QALYs for diagnostic tests in the scenario analysis and basic model. Table 3. Total one year’s outcome and incremental cost-effectiveness ratio (ICER) for basic and scenario models. Costs (€) QALYs Comparator Incremental Incremental ICER Costs (€) QALYs (€ per QALY) Base case analysis DSA 39.808 0,6039 CTA 40.748 0,5983 DSA 940 -0,004 Dominated MRA 41.814 0,5947 DSA 1.066 -0,009 Dominated Base case analysis DSA 39.808 0,6039 CTA 39.767 0,6039 DSA -41 0,000 Dominant MRA 39.851 0,6039 CTA 84 0,000 Dominated
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