Tiotropium bromide in the routine care of GOLD stage II COPD patients: a pharmaeconomic evaluation

Background: a secondary pre-specified analysis of the UPLIFT cohort demonstrated that the inclusion of tiotropium bromide in the routine care of GOLD stage II (moderate) chronic obstructive pulmonary disease (COPD) patients is associated with stronger improvements of survival, quality of life, and exacerbation rate than those shown in the total cohort; in this subgroup, tiotropium furthermore induces a significant reduction in the rate of FEV1 decline. Objective: to adapt the Spiriva® model, originally built to evaluate cost-effectiveness of tiotropium inclusion in the general COPD population, to GOLD II patients. Methods: the Spiriva® model is a probabilistic Markov patient-level simulation developed over a lifetime horizon to compare outcomes associated with the inclusion of tiotropium in routine care (RC) for COPD treatment with those obtained with RC alone. Patients are characterised by gender, age, height, smoking status and FEV1. Model structure and sources have been maintained unvaried, except for demographic characteristics, specific for GOLD II patients, as extrapolated from an Italian observational study, and tiotropium efficacy, based on the secondary analysis of GOLD II UPLIFT patients. As in the original model, only direct health care costs are considered. Results: patients treated with tiotropium on average (95% CI) gain 0.70 (0.00/7.23) LYs or 0.77 (0.02/4.67) QALYs compared to RC. The incremental lifetime cost is € 3,520 (-6,391/26,686), meaning that the incremental cost required to gain a QALY (incremental cost-effectiveness ratio – ICER) is equal to € 4,548. Sensitivity analysis shows that tiotropium has a 50% probability of being cost-effective for a willingness-to-pay (WTP) around 4,600 €/QALY; 100% probability is achieved with a WTP of € 9,300. Conclusions: the adoption of a strategy based on the inclusion of tiotropium from the early COPD stages represents good value for money in Italy, as the ICER estimated for GOLD II patients is well below conventional WTP thresholds, and lower than that calculated for the entire UPLIFT cohort.