Dealing with Ignored Attributes in Choice Experiments on Valuation of Sweden’s Environmental Quality Objectives

Using a choice experiment, this paper investigates how Swedish citizens value three environmental quality objectives. In addition, a follow-up question is used to investigate whether respondents ignored any attributes when responding. The resulting information is used in model estimation by restricting the individual parameters for the ignored attributes to zero. When taking the shares of respondents who took both the environmental and the cost attributes (52–69% of the respondents) into account, then the WTP for each attribute changes if the respondents who ignored the attributes have a zero WTP. At the same time, we find evidence that not all respondents who claimed to have ignored an attribute really did. However, the most commonly ignored non-monetary attributes always have the lowest rankings in terms of WTP across all three environmental objectives. Thus, our results show that instead of ignoring attributes completely, respondents seem to put less weight on the attributes they claimed to have ignored.     

Evaluating the cost-effectiveness of percutaneous closure of a patent foramen ovale versus medical management in patients with a cryptogenic stroke: from the UK payer perspective

Aims: Percutaneous closure of a patent foramen ovale (PFO) is known to lower the risk of recurrent stroke in patients with a cryptogenic stroke. However, the economic implications of transcatheter PFO closure are less well known. From a UK payer perspective, a detailed economic appraisal of PFO closure was performed for prevention of recurrent ischemic stroke in patients with a PFO who had experienced a cryptogenic stroke.

Materials and methods: A Markov cohort model was constructed using a 5-year time-horizon with a patient mean age of 45.2 years, reflecting the characteristics reported in the REDUCE trial. Transition probabilities, clinical inputs, costs, and utility values were ascertained from published and national costing sources. Total costs, incremental costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios were calculated, utilizing a discount rate of 3.5%. A range of univariate and probabilistic sensitivity analyses were also performed.

Results: When applying a willingness-to-pay (WTP) threshold of £20,000/QALY in accordance with NICE guidelines, PFO closure compared with antiplatelet therapy alone showed a beneficial cost/QALY of £18,584, attained at 4 years. Applying discount rates of 0% and 6% had a negligible effect on the base-case model findings. PFO closure demonstrated a 76.9% probability of being cost-effective at a WTP threshold of £20,000/QALY at a 5-year time-horizon.

Limitations: This model focused specifically on UK stroke patients and typically enrolled young (mean age <65 years old) patients. Hence, caution should be taken when comparing data vs non-UK populations, and it remains unclear how older patients might have affected cost-effectiveness findings, as the risk of paradoxical embolism can persist as patients age.

Conclusion: Percutaneous closure of a PFO is cost-effective compared with antiplatelet therapy alone, underlining the economic benefits potentially afforded by this treatment in selected patients.     

Cost-effectiveness of percutaneous closure of a patent foramen ovale compared with medical management in patients with a cryptogenic stroke: from the US payer perspective

Abstract

Aims: To evaluate the cost-effectiveness of percutaneous patent foramen ovale (PFO) closure, from a US payer perspective. Lower rates of recurrent ischemic stroke have been documented following percutaneous PFO closure in properly selected patients. Stroke in patients aged <60?years is particularly interesting because this population is typically at peak economic productivity and vulnerable to prolonged disability.

Materials and methods: A Markov model comprising six health states (Stable after index stroke, Transient ischemic attack, Post-Transient Ischemic Attack, Clinical ischemic stroke, Post-clinical ischemic stroke, and Death) was constructed to evaluate the cost-effectiveness of PFO closure in combination with medical management versus medical management alone. The base-case model employed a 5-year time-horizon, with transition probabilities, clinical inputs, costs, and utility values ascertained from published and national costing sources. Incremental cost-effectiveness ratio (ICER) was evaluated per US guidelines, utilizing a discount rate of 3.0%.

Results: At 5?years, overall costs and quality-adjusted life-years (QALYs) obtained from PFO closure compared with medical management were $16,323 vs $7,670 and 4.18 vs 3.77, respectively. At 5?years, PFO closure achieved an ICER of $21,049, beneficially lower than the conventional threshold of $50,000. PFO closure reached cost-effectiveness at 2.3?years (ICER = $47,145). Applying discount rates of 0% and 6% had a negligible impact on base-case model findings. Furthermore, PFO closure was 95.4% likely to be cost-effective, with a willingness-to-pay (WTP) threshold of $50,000 and a 5-year time horizon.

Limitations: From a cost perspective, our economic model employed a US patient sub-population, so cost data may not extrapolate to other non-US stroke populations.

Conclusion: Percutaneous PFO closure plus medical management represents a cost-effective approach for lowering the risk of recurrent stroke compared with medical management alone.