Zsa Zsa Weerts

Cost-effectiveness of peppermint oil in IBS 199 8 0% 20% 40% 60% 80% 100% Probability small�intestinal release peppermint oil cost�effective compared to placebo Cost�effectiveness threshold (€) Figure 8.2 Cost-effectiveness acceptability curve. The line indicates the probability (y-axis) of a treatment being cost-effective, i.e ., the proportion of replications small-intestinal release peppermint oil has the highest net monetary benefit, given various levels of willingness to pay (cost-effectiveness thresholds (x-axis). Table 8.4 Results of primary and sensitivity analyses (ITT-population). Effect Costs (€) Quadrant (%) # Probability of cost effectiveness at WTP (%) NE NW SE SW €5.000 €10.000 Cost utility, primary analysis (corrected QALY) Sensitivity analysis Cost-effectiveness, responder ratio § Cost utility, uncorrected QALY Cost utility, health-care perspective 0.004 12.4 0.006 0.004 -40 -40 -40 -195 31 41 40 15 18 5 6 5 46 51 51 65 5 3 3 15 53 89 56 83 56 92 58 85 WTP willingness to pay; NE North-east; NW North-west; SE south-east; SW south-west; QALY quality adjusted life years. # The four quadrants represent four different situations of cost-effectiveness compared to placebo. If the majority of the bootstrapped ICERs (incremental cost-effectiveness ratio) appear in the south- east quadrant of the figure, this indicates that treatment is dominant. If the majority of the bootstrapped ICERs appear in the north-west quadrant of the figure, this indicates that treatment is inferior; § The primary clinical endpoint was the percentage (%) of abdominal pain responders, according to FDA definition, with a responder being a patient with at least 30% decrease in the weekly average of worst daily abdominal pain (scored on an 11-point NRS) compared to baseline, in at least 50% of the treatment period, i.e . in this study four weeks.