Base-case analyses showed that triple therapy was associated with higher costs and QALYs than dual therapy. The model suggests a potential gain of 1.55 QALYs per patient per year on triple therapy with respect to dual therapy. In the analysis of the Markov cohort model, we estimated a median probability of surviving free of exacerbation of 0.87 and 0.85 for triple and dual therapy, respectively. We observed a difference of US$304 in total discounted cost per person-year on triple therapy concerning dual therapy, Table 2. The incremental cost-effectiveness ratio was US$196 in the probabilistic model and US$589 in the deterministic model.
In the deterministic sensitivity analysis, our base-case results were robust to variations in all assumptions and parameters. For none of the variables evaluated, variations within the established ranges led to the incremental cost-effectiveness ratio being higher than the WTP, Figure 2. The results of the probabilistic sensitivity analysis are graphically represented in the cost-effectiveness plane, Figure 3. This scatter plot shows that compared with dual therapy, treatment with triple therapy tends to be associated with lower costs and higher QALY. Indeed, 80% in quadrant 1 (high cost, high QALYs) and 20% in quadrant 4 (high cost, lower QALYs). The cost-effectiveness acceptability curve shows that triple therapy becomes cost-effective after willingness-to-pay thresholds of US$700; Figure 4.
BMC Pulm Med. 2021;21(398) © 2021 BioMed Central, Ltd.