Cost-effectiveness analysis when the WTA is greater than the WTP

Valuing Protected Areas: Socioeconomic Determinants of the Willingness to Pay for the National Park

The study aimed at estimating the variability of perception of the Wielkopolski National Park (WNP) value among different groups of society. The study was based on questionnaires conducted in 2018. Analyses were carried out on the basis of 1350 records. The results of the survey were subjected to statistical analysis using the canonical correspondence analysis (CCA) and the analysis of variance. The study revealed that the relation with the natural environment significantly differs among various groups of society. The application of diverse analytical tools in relation to the survey data allowed for the quantification of that diversity. The relationship between the economic situation of respondents and their willingness to pay for nature conservation is non-linear.

Cost-utility analysis of telephone-based cognitive behavior therapy in chronic obstructive pulmonary disease (COPD) patients with anxiety and depression comorbidities: an application for willingness to accept concept

BACKGROUND

This study evaluated the cost-utility of telephone-based cognitive behavioral therapy (TB-CBT) (experimental arm) in comparison with a placebo-befriending (control arm) program in COPD participants with mild to severe depression and/or anxiety.

METHODS

The decision rule was based on willingness-to-pay if there is an increased unit of effectiveness (a quality-adjusted life year [QALY] gain) and an increase in cost, and willingness-to-accept (WTA) if there is a reduced unit of effectiveness (a QALY loss) and decrease in cost (a cost-saving).

RESULTS

TB-CBT group was associated with a reduction in the incremental cost of AUS-$407.3 (p < 0.001, SE:34.1) plus a negative, nonsignificant incremental QALY gain of -0.008 (SE:0.011) per patient compared to control group. The point estimate of the mean incremental cost-utility ratio was AUS$50,284.0 cost saving per QALY sacrificed (the high value associated with small QALY value in the denominator). Ninety-five percent CI was AUS$13,426 cost sacrificed to AUS$32,018 cost gain (lower values associated with larger QALY values in the denominator). If the societal's minimum (flooring threshold) WTA is AUS$64,000 per QALY forgone, the probability of TB-CBT being cost-effective was 42% Conclusions: This study showed that TB-CBT can be recommended as a cost-saving and preventive approach over usual care plus befriending program.

Kinky thresholds revisited: opportunity costs differ in the NE and SW quadrants

Historically, a kinked threshold line on the cost-effectiveness plane at the origin was suggested due to differences in willingness to pay (WTP) for health gain with trade-offs in the north-east (NE) quadrant versus willingness to accept (WTA) cost reductions for health loss with trade-offs in the south-west (SW) quadrant. Empirically, WTA is greater than WTP for equivalent units of health, a finding supported by loss aversion under prospect theory. More recently, appropriate threshold values for health effects have been shown to require an endogenous consideration of the opportunity cost of alternative actions in budget-constrained health systems, but also allocative and displacement inefficiency observed in health system practice. Allocative and displacement inefficiency arise in health systems where the least cost-effective program in contraction has a higher incremental cost-effectiveness ratio (ICER = m) than the most cost-effective program in expansion (ICER = n) and displaced services (ICER = d), respectively. The health shadow price derived by Pekarsky, [Formula: see text] reflects the opportunity cost of best alternative adoption and financing actions in reimbursing new technology with expected incremental costs and net effect allowing for allocative (n < m), and displacement, inefficiency (d < m). This provides an appropriate threshold value for the NE quadrant. In this paper, I show that for trade-offs in the SW quadrant, where new strategies have lower expected net cost while lower expected net effect than current practice, the opportunity cost is contraction of the least cost-effective program, with threshold ICER m. That is, in the SW quadrant, the cost reduction per unit of decreased effect should be compared with the appropriate opportunity cost, best alternative generation of funding. Consequently, appropriate consideration of opportunity cost produces a kink in the threshold at the origin, with the health shadow price in the NE quadrant and ICER of the least cost-effective program in contraction (m) in the SW quadrant having the same general shape as that previously suggested by WTP versus WTA. The extent of this kink depends on the degree of allocative and displacement inefficiency, with no kink in the threshold line strictly only appropriate with complete allocative and displacement efficiency, that is n = d = m.

WTP and WTA: do people think differently?

Contingent valuation (CV) studies in health care have used the willingness to pay (WTP) approach, to the virtual exclusion of willingness to accept (WTA). Outside the health care field, disparities between WTP and WTA values have been observed. Were such disparities to be demonstrated for health care technologies, the conventional assumption of a linear cost-effectiveness plane would be invalidated. This paper employs data derived from interviews with users of the UK's paediatric cochlear implantation (PCI) programme based in Nottingham (i) to assess the feasibility of estimating WTA for the potential discontinuation of an existing technology, and (ii) to investigate any WTA-WTP disparity which might be revealed. Only one-third of subjects providing WTP values were willing and able to offer a corresponding WTA value. Our qualitative data revealed that modes of response differed between the two valuation approaches. In particular, the presumption of fungibility of the health care intervention was a far more serious obstacle to completing the WTA task than it was for WTP. Among those prepared to offer values under both approaches, mean WTA was approximately four times mean WTP. Until more health studies are conducted, it remains unclear whether or not the findings are specific both to the intervention and to the elicitation format.

Bayesian statistics in medicine: a 25 year review

This review examines the state of Bayesian thinking as Statistics in Medicine was launched in 1982, reflecting particularly on its applicability and uses in medical research. It then looks at each subsequent five-year epoch, with a focus on papers appearing in Statistics in Medicine, putting these in the context of major developments in Bayesian thinking and computation with reference to important books, landmark meetings and seminal papers. It charts the growth of Bayesian statistics as it is applied to medicine and makes predictions for the future. From sparse beginnings, where Bayesian statistics was barely mentioned, Bayesian statistics has now permeated all the major areas of medical statistics, including clinical trials, epidemiology, meta-analyses and evidence synthesis, spatial modelling, longitudinal modelling, survival modelling, molecular genetics and decision-making in respect of new technologies.

Cost-effectiveness acceptability curves and a reluctance to lose

Cost-effectiveness acceptability curves (CEACs) are a method used to present uncertainty surrounding incremental cost-effectiveness ratios (ICERs). Construction of the curves relies on the assumption that the willingness to pay (WTP) for health gain is identical to the willingness to accept (WTA) health loss. The objective of this paper is to explore the impact that differences between WTP and WTA health changes have on CEACs. Previous empirical evidence has shown that the relationship between WTP and WTA is not 1:1. The discrepancy between WTP and WTA for health changes can be expressed as a ratio: the accept/reject ratio (which can vary between 1 and infinity). Depending on this ratio, the area within the southwest quadrant of the cost-effectiveness plane in which any bootstrap cost-effect pairs will be considered to be cost effective will be smaller, resulting in a lower CEAC. We used data from two clinical trials to illustrate that relaxing the 1:1 WTP/WTA assumption has an impact on the CEACs. Given the difficulty in assessing the accept/reject ratio for every evaluation, we suggest presenting a series of CEACs for a range of values for the accept/reject ratio, including 1 and infinite. Although it is not possible to explain this phenomenon within the extra-welfarist framework, it has been shown empirically that individuals give a higher valuation to the removal of effective therapies than to the introduction of new therapies that are more costly and effective. In cost-effectiveness analyses where uncertainty of the ICER covers the southwest quadrant of the cost-effectiveness plane, the discrepancy between societies' WTP and WTA should be indicated by drawing multiple CEACs.

New and dis-improved: on the evaluation and use of less effective, less expensive medical interventions

The innovation and diffusion of new technologies is in large measure responsible for the persistent rise in the cost of health care. The increasing cost of health care, in turn, will make cost-saving technologies more attractive. When cost-saving technologies lead to better or equivalent outcomes, their acceptance will not be controversial. However, the necessary conditions for the development and clinical acceptance of cost-saving technologies that might diminish the quality of health care have not been systematically considered. Indeed, as the clinical research enterprise has been focused almost entirely on quality-improving (or quality-neutral) innovations, new concepts may need to be introduced for quality-reducing innovations. Although the development of such therapies would, at least in some circumstances, increase overall societal benefits, replacing a standard therapy with a less effective one may conflict with deeply held values, such that conventional cost-effectiveness benchmarks might not apply. In addition, from a clinical research perspective, there are considerable ethical and methodologic hurdles that might impede the development of less expensive, less intensive therapies. In this article, using a hypothetical scenario, the authors consider economic, ethical, and research design issues concerning the innovation and diffusion of less effective, less expensive therapies and introduce 2 concepts--"decremental cost-effectiveness" and "acceptability trials"--that may in part provide a research framework for the study of "new and dis-improved" therapies.

Cost-effectiveness of oral phenytoin, intravenous phenytoin, and intravenous fosphenytoin in the emergency department

STUDY OBJECTIVE

Oral phenytoin, intravenous phenytoin, and intravenous fosphenytoin are all commonly used for loading phenytoin in the emergency department (ED). The cost-effectiveness of each was compared for patients presenting with seizures and subtherapeutic phenytoin concentrations.

METHODS

A simple decision tree was developed to determine the treatment costs associated with each of 3 loading techniques. We determined effectiveness by comparing adverse event rates and by calculating the time to safe ED discharge. Time to safe ED discharge was defined as the time at which therapeutic concentrations of phenytoin (>or=10 mg/L) were achieved with an absence of any adverse events that precluded discharge. The comparative cost-effectiveness of alternatives to oral phenytoin was determined by combining net costs and number of adverse events, expressed as cost per adverse events avoided. Cost-effectiveness was also determined by comparing the net costs of each loading technique required to achieve the time to safe ED discharge, expressed as cost per hour of ED time saved. The outcomes and costs were primarily derived from a prospective, randomized controlled trial, augmented by time-motion studies and alternate-cost sources. Costs included the cost of drugs, supplies, and personnel. Analyses were also performed in scenarios incorporating labor costs and savings from using a lower-urgency area of the ED.

RESULTS

The mean number of adverse events per patient for oral phenytoin, intravenous phenytoin, and intravenous fosphenytoin was 1.06, 1.93, and 2.13, respectively. Mean time to safe ED discharge in the 3 groups was 6.4 hours, 1.7 hours, and 1.3 hours. Cost per patient was 2.83 dollars, 21.16 dollars, and 175.19 dollars, respectively, and did not differ substantially in the Labor and Triage (lower-urgency area of ED) scenarios. When the measure of effectiveness was adverse events, oral phenytoin dominated intravenous phenytoin and intravenous fosphenytoin, with a lower cost and number of adverse events. With time to safe ED discharge as the outcome measure, the incremental cost-effectiveness ratios were 3.90 dollars and 387.27 dollars per hour of ED time saved for oral phenytoin versus intravenous phenytoin and for intravenous fosphenytoin versus intravenous phenytoin, respectively.

CONCLUSION

Oral phenytoin is the most cost-effective loading method in most settings. Intravenous phenytoin is preferred if one is willing to pay an additional 20.65 dollars to 44.25 dollars per patient and willing to have more adverse events for a quicker average time to safe ED discharge. It is unlikely that intravenous fosphenytoin is justifiable in any setting.

Using inverse-weighting in cost-effectiveness analysis with censored data

Due to induced dependent censoring, estimating mean costs and quality-adjusted survival in a cost-effectiveness analysis using standard life-table methods leads to biased results. In this paper we propose methods for estimating the difference in mean costs and the difference in effectiveness, together with their respective variances and covariance in the presence of dependent censoring. We consider the situation in which the measure of effectiveness is either the probability of patients surviving a duration of interest, mean survival time over a duration of interest or mean quality-adjusted survival time over a duration of interest. The method of inverse-weighting is used for censored cost and quality of life data. The methods are illustrated in an example using an incremental net benefit analysis.

Randomized controlled economic evaluation of asthma self-management in primary health care

In this randomized controlled economic evaluation we compared guided asthma self-management with usual asthma care according to guidelines for Dutch family physicians. Nineteen family practices were randomized, and 193 adults with stable asthma (98 self-management, 95 usual care) were included and monitored for 2 years. We hypothesized that introducing self-management would not compromise asthma control and cost would be equal to or lower than in usual care. Patient-specific cost data were collected, preference-based utilities were assessed, and incremental cost per quality-adjusted life year (QALY) and successfully treated week gained was calculated. Self-management patients gained 0.039 QALY (95% confidence interval [CI], 0.003 to 0.075) and experienced 81 (95% CI, 78 to 84) successfully treated weeks in 2 years' time; the corresponding figures for usual care were 0.024 (95% CI, -0.022 to 0.071) and 75 (95% CI, 72 to 78). Total costs were 1,084 euros(95% CI, 938 to 1,228) for self-management and 1,097 euros (95% CI, 933 to 1,260) for usual care. Self-management patients consumed 1,680 (95% CI, 1,538 to 1,822) puffs of budesonide, usual care patients 1,897 (95% CI, 1,679 to 2,115). Mean productivity cost due to limited activity days was 213 euros lower among self-management patients. When all costs were included, self-management was cost-effective on all outcomes. The probability that self-management was cost-effective relative to usual care in terms of QALYs was 52%. We conclude that guided self-management is a safe and efficient alternative approach compared with asthma treatment usually provided in Dutch primary care.