Zsa Zsa Weerts

Chapter 8 198 �€ 1,500 �€ 1,000 �€ 500 € 0 € 500 € 1,000 € 1,500 �0.03 �0.02 �0.01 0 0.01 0.02 0.03 Difference in costs Difference in mean QALY Figure 8.1 Cost-effectiveness plane of small-intestinal release compared with placebo. Each data-point represents 1 bootstrapped estimate of incremental costs and baseline corrected QALYs. The bootstrapped ICERs cover all four quadrants in both planes, indicating some uncertainty of the data. 46% of simulations lie in the south-east quadrant, the quadrant indicating dominance of peppermint oil. 31% of simulations lie in the north-east quadrant, indicating higher efficacy but at higher cost. The cost-effectiveness acceptability curve ( Figure 8.2 ) shows the probability peppermint oil is cost-effective at different WTP-thresholds. Sensitivity analyses The results from the sensitivity analysis are presented in Table 8.4. When using the main clinical outcome instead of QALY, the proportion of abdominal pain responders did not differ significantly between both groups: 22/64, 29/62 in the placebo and small- intestinal peppermint oil group, respectively. 9 The cost-effectiveness plane showed that small-intestinal release peppermint oil is dominant in 51% of ICER simulations and more effective at higher cost in 41% of simulations. At a WTP-threshold of €5.000 per additional responder, the probability of small-intestinal release peppermint oil being cost-effective is 89% ( Figure 8.3 ).