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Methodological limitations of economic evaluations of antenatal screening.

A review of recent economic studies of antenatal screening reveals widespread violation of accepted economic evaluation methodology. In particular, the costs and benefits of antenatal screening are often misclassified and conflated, and the non-resource effects of averted costs are often excluded from the evaluation process. The result is a widespread violation of the explicit and systematic approaches taken by economic analysts more generally, and conclusions that may be described as misleading. This letter calls for economic analysts to be consistent in their application of economic evaluation methodology to antenatal screening programmes.

Abortion, Legal↗

Affordability and cost-effectiveness: decision-making on the cost-effectiveness plane.

Much recent research interest has focused on handling uncertainty in cost-effectiveness analysis and in particular the calculation of confidence intervals for incremental cost-effectiveness ratios (ICERs). Problems of interpretation when ICERs are negative have led to two important and related developments: the use of the net-benefit statistic and the presentation of uncertainty in cost-effectiveness analysis using acceptability curves. However, neither of these developments directly addresses the problem that decision-makers are constrained by a fixed-budget and may not be able to fund new, more expensive interventions, even if they have been shown to represent good value for money. In response to this limitation, the authors introduce the 'affordability curve' which reflects the probability that a programme is affordable for a wide range of threshold budgets. The authors argue that the joint probability an intervention is affordable and cost-effective is more useful for decision-making since it captures both dimensions of the decision problem faced by those responsible for health service budgets.

Budgets↗

Opportunity costs and uncertainty in the economic evaluation of health care interventions.

Considerable methodological research has been conducted on handling uncertainty in cost-effectiveness analysis. The current literature suggests the concepts of net health benefits and cost-effectiveness acceptability curves to circumvent the technical shortcomings of cost-effectiveness ratio statistics. However, these approaches do not provide a solution for the inherent problem that the threshold cost-effectiveness ratio itself is unknown. The authors suggest analysing uncertainty in cost-effectiveness analysis by directly addressing the concept of opportunity costs using the decision rule described by Birch and Gafni (1992) and introduce a new graphical framework (the "decision making plane") for communicating with policy makers.

Budgets↗

The distribution problem in economic evaluation: income and the valuation of costs and consequences of health care programmes.

To date, a common view in the health economics literature is that the applicability of cost-benefit analysis (CBA) is limited, due to the distribution problem which underlies its main method of valuation (e.g. willingness to pay). One view is that cost effectiveness analysis (CEA) overcomes these problems. We show that the same distributional concerns apply to non-monetary valuations of health consequences, to measurement of costs and to the decision rules of CEA. Hence adopting CEA over CBA cannot be justified on the basis of "avoiding" distributional considerations. The implications of our results are discussed, including alternative strategies for the use of "income-based" research findings in social decision-making.

Consumer Behavior↗

Measuring the social importance of concentration or dispersion of individual health benefits.

In this paper we address the importance of distributive preferences in the social valuation of quality-adjusted life years (QALYs). We propose a social welfare function that generalises the functions traditionally used in the health economic literature. The novelty is that, depending on the individual health gains, this function can represent either preferences for concentrating or preferences for spreading total gain or both together, an issue which has not been addressed until now. Based on an experiment, we observe that this generalisation provides a suitable approximation to the sampled social preferences.

Consumer Behavior↗

A general model of the impact of absenteeism on employers and employees.

Most studies on the indirect costs of an illness and the cost effectiveness of a medical intervention or employer-sponsored wellness program assume that the value of reducing the number of days employees miss from work due to illness is the wage rate. This paper presents a general model to examine the magnitude and incidence of costs associated with absenteeism under alternative assumptions regarding the size of the firm, the production function, the nature of the firm's product, and the competitiveness of the labor market. We conclude that the cost of lost work time can be substantially higher than the wage when perfect substitutes are not available to replace absent workers and there is team production or a penalty associated with not meeting an output target. In the long run, workers are likely to bear much of the incidence of the costs associated with absenteeism, and therefore be the likely beneficiaries of any reduction in absenteeism.

Absenteeism↗

Testing the convergent validity of the contingent valuation and travel cost methods in valuing the benefits of health care.

In this study, the convergent validity of the contingent valuation method (CVM) and travel cost method (TCM) is tested by comparing estimates of the willingness to pay (WTP) for improving access to mammographic screening in rural areas of Australia. It is based on a telephone survey of 458 women in 19 towns, in which they were asked about their recent screening behaviour and their WTP to have a mobile screening unit visit their nearest town. After eliminating missing data and other non-usable responses the contingent valuation experiment and travel cost model were based on information from 372 and 319 women, respectively. Estimates of the maximum WTP for the use of mobile screening units were derived using both methods and compared. The highest mean WTP estimated using the TCM was $83.10 (95% C.I. $99.06-$68.53), which is significantly less than the estimate of $148.09 ($131.13-$166.60) using the CVM. This could be due to the CVM estimates also reflecting non-use values such as altruism, or a range of potential biases that are known to affect both methods. Further tests of validity are required in order to gain a greater understanding of the relationship between these two methods of estimating WTP.

Bias↗

Measuring willingness-to-pay for risk reduction: an application of conjoint analysis.

This study applies conjoint analysis (CA) to estimate the marginal willingness-to-pay (MWTP) of elderly individuals for a reduction of the risk of fracture of the femur. The good in question is a hypothetical hip protector which lowers the risk of a fracture by different amounts. Other attributes are ease of handling, wearing comfort, and out-of-pocket cost, which are traded off against risk reduction. In 500 face-to-face interviews, pensioners stated whether or not they would buy the product. Results suggest that MWTP for wearing comfort exceeds that for risk reduction. Indeed, willingness-to-pay for the product as a whole is negative, indicating that it should not be included as a mandatory benefit in health insurance.

Accidental Falls↗

Is there a kink in consumers' threshold value for cost-effectiveness in health care?

BACKGROUND: A reproducible observation is that consumers' willingness-to-accept (WTA) monetary compensation to forgo a program is greater than their stated willingness-to-pay (WTP) for the same benefit. Several explanations exist, including the psychological principle that the utility of losses weighs heavier than gains. We sought to quantify the WTP-WTA disparity from published literature and explore implications for cost-effectiveness analysis accept-reject thresholds in the south-west quadrant of the cost-effectiveness plane (less effect, less cost). METHODS: We reviewed published studies (health and non-health) to estimate the ratio of WTA to WTP for the same program benefit for each study and to determine if WTA is consistently greater than WTP in the literature. RESULTS: WTA/WTP ratios were greater than unity for every study we reviewed. The ratios ranged from 3.2 to 89.4 for environmental studies (n=7), 1.9 to 6.4 for health care studies (n=2), 1.1 to 3.6 for safety studies (n=4) and 1.3 to 2.6 for experimental studies (n=7). CONCLUSIONS: Given that WTA is greater than WTP based on individual preferences, should not societal preferences used to determine cost-effectiveness thresholds reflect this disparity? Current convention in cost-effectiveness analysis is that any given accept-rejection criterion (e.g. $50 k/QALY gained) is symmetric - a straight line through the origin of the cost-effectiveness plane. The WTA-WTP evidence suggests a downward 'kink' through the origin for the south-west quadrant, such that the 'selling price' of a QALY is greater than the 'buying price'. The possibility of 'kinky cost-effectiveness' decision rules and the size of the kink merits further exploration.

Attitude to Health↗

Unit root properties of OECD health care expenditure and GDP data.

This note reconsiders the unit root properties of health care expenditure (HCE) and gross domestic product (GDP) for OECD countries. The time-series properties of this data set has been much discussed in the literature with contrasting results from the application of a range of test procedures. We use a recently developed test to examine the relationship between the two variables. The results in this paper confirm earlier findings that when the data are considered as a panel, there is strong evidence of unit roots in both GDP and HCE data.

Cross-Cultural Comparison↗

Neonatal health care costs related to smoking during pregnancy.

RESEARCH OBJECTIVE: Much of the work on estimating health care costs attributable to smoking has failed to capture the effects and related costs of smoking during pregnancy. The goal of this study is to use data on smoking behavior, birth outcomes and resource utilization to estimate neonatal costs attributable to maternal smoking during pregnancy. STUDY DESIGN: We use 1995 data from the Center for Disease Control's (CDC) Pregnancy Risk Assessment Monitoring System (PRAMS) database. The PRAMS collects representative samples of births from 13 states (Alabama, Alaska, California, Florida, Georgia, Indiana, Maine, Michigan, New York (excluding New York City), Oklahoma, South Carolina, Washington, and West Virginia), and the District of Columbia. The 1995 PRAMS sample is approximately 25 000. Multivariate analysis is used to estimate the relationship of smoking to probability of admission to an NICU and, separately, the length of stay for those admitted or not admitted to an NICU. Neonatal costs are predicted for infants 'as is' and 'as if' their mother did not smoke. The difference between these constitutes smoking attributable neonatal costs; this divided by total neonatal costs constitutes the smoking attributable fraction (SAF). We use data from the MarketScantrade mark database of the MedStattrade mark Corporation to attach average dollar amounts to NICU and non-NICU nursery nights and data from the 1997 birth certificates to extrapolate the SAFs and attributable expenses to all states. PRINCIPAL FINDINGS: The analysis showed that maternal smoking increased the relative risk of admission to an NICU by almost 20%. For infants admitted to the NICU, maternal smoking increased length of stay while for non- NICU infants it appeared to lower it. Over all births, however, smoking increased infant length of stay by 1.1%. NICU infants cost $2496 per night while in the NICU and $1796 while in a regular nursery compared to only $748 for non-NICU infants. The combination of the increased NICU use, longer stays and higher costs result in a positive smoking attributable fraction (SAF) for neonatal costs. The SAF across all states is 2.2%. Across the states, the SAF varied from a low of 1.3% in Texas to a high of 4.6% in Indiana. CONCLUSIONS: These results further confirm the adverse effects of smoking. Among mothers who smoke, smoking adds over $700 in neonatal costs. The smoking attributable neonatal costs in the US represent almost $367 million in 1996 dollars; these costs vary from less than a million in smaller states to over $35 million in California. These costs are highly preventable since the adverse effects of maternal smoking occur in the short-run and can be avoided by even a temporary cessation of maternal smoking. These cost estimates can be used by managed care plans, state and local public health officials and others to evaluate alternative smoking cessation programs.

Adolescent↗

How profitable is risk selection? A comparison of four risk adjustment models.

To mitigate selection triggered by capitation payments, risk-adjustment models bring capitation payments closer on average to individuals' expected expenditure. We examine the maximum potential profit that plans could hypothetically gain by using their own private information to select low-cost enrollees when payments are made using four commonly used risk adjustment models. Simulations using a privately insured sample suggest that risk selection profits remain substantial. The magnitude of potential profit varies according to the risk adjustment model and the private information plans can employ to identify profitable enrollees.

Actuarial Analysis↗

On the empirical association between poor health and low socioeconomic status at old age.

Epidemiologic studies using mortality rates as indicators of health fail to find any meaningful association between poor health and low socioeconomic status in older age-groups, whereas economic studies using self-assessed health consistently find a significant positive correlation, even after controlling for self-reporting errors. Such contradictory results have not been reported for working age individuals. A simple explanation might be that the elderly samples on which the epidemiologic and economic studies are based come from different populations. However, this paper shows that similar contradictory results are obtained even when the same samples are used, simply by switching between self-assessed health and mortality as health indicators. An alternative explanation is proposed, namely that these health indicators yield different results because they relate to different ranges of the latent health variable at old age.

Aged↗

Do Medicare HMOs still reduce health services use after controlling for selection bias?

This study models the relationship between Medicare beneficiary decisions to join Medicare HMOs and subsequent health services utilization. The relationship between health plan choice and utilization is thought to be endogenous because of favorable selection into HMOs. Previous studies found significantly lower inpatient utilization among Medicare HMO enrollees than among nonenrollees, but lacked strong controls for selection bias. Thus, a firm conclusion could not be drawn as to whether the observed differences were attributable to the HMO practice setting or to baseline differences in the illness profiles of the two groups studied. The present study uses simultaneous equations methods, including discrete factor estimation, to test the effect of Medicare HMOs on utilization when strong controls for selection bias are imposed. The model was run on a panel of 1993-1996 data from the Medicare Current Beneficiary Survey, supplemented with linked data on Medicare HMO characteristics and area supply characteristics. The study found that even when favorable selection is controlled for, Medicare HMOs significantly reduce both the probability of hospitalization and the number of inpatient days used by those who are hospitalized. Medicare HMOs do not, however, appear to reduce the use of physician services.

Aged↗

Estimating an EQ-5D population value set: the case of Japan.

Quality adjustment weights for quality-adjusted life years (QALYs) are available with the EQ-5D Instrument, which are based on a survey that quantified the preferences of the British public. However, the extent to which this British value set is applicable to other, especially non-European, countries is yet unclear. The objectives of this study are (a) to compare the valuations obtained in Japan and Britain, and (b) to explore a local Japanese value set. A diminished study design is employed, where 17 hypothetical EQ-5D health states are evaluated as opposed to 42 in the British study. The official Japanese version of the instrument and the Time Trade-Off method are used to interview 543 members of the public. The results are: firstly, the evaluations obtained in Japan and those from Britain differ by 0.24 on average on a [-1, +1] scale, and mean absolute error (MAE) in predicting the Japanese preferences with the British value set is 0.23. Secondly, comparable regressions suggest that the two peoples have systematically different preference structures (p<0.001 for 8 of 12 coefficients; F-test). Thirdly, using alternative models, the predictions are improved so that the local Japanese value set achieves MAE in the order of 0.01.

Attitude to Health↗

Does prospective payment reduce inpatient length of stay?

A change in payment mechanism for inpatient care from per diem to per episode creates two incentives - a marginal and an average price effect - to change length of stay. The decrease in marginal price per day to zero should reduce the length of stay, while an increase in average price per inpatient stay should increase the length of stay. This study uses data from a natural experiment to estimate both marginal and average price elasticities, and to test whether the length of stay falls after the introduction of prospective payment in a sample of 8509 severely mentally ill patients. We estimate that the marginal price elasticity is zero, but the average price elasticity is between 0.16 and 0.20. The results were generally robust for short- and long stayers, and for persons admitted early and late after the change in payment mechanism. The model controlled for hospital fixed effects and individual random effects.

Adolescent↗

The benefits of switching smoking cessation drugs to over-the-counter status.

This paper provides an analysis of the benefits to society from the conversion of nicotine replacement drugs (nicotine patches and gum) in 1996 from sale by prescription only in the United States to over-the-counter (OTC) sales. To estimate these benefits, we first estimate statistical demand functions for nicotine patches and gum. Second, we calculate the effects of OTC conversion on sales of each type of nicotine replacement drug. Third, we survey the literature on the effects of nicotine replacement drugs on total quits of cigarette smoking. Fourth, we survey the literature on the effects of quits achieved on expected lifespan, and on the estimated monetary value of longer lives from smoking cessation. Finally, we use all this evidence to calculate the value of the social benefits of the OTC conversion to the US. As a result of the OTC conversion, consumption of nicotine replacement drugs has increased substantially, by 78-92% for nicotine patches and 180% for nicotine gum. We estimate that the resulting increase in smoking cessation generated annual net social benefits of the order of magnitude of 1.8-2 billion dollars, based on conservative estimates both of the number of quits achieved and the value of added quality-adjusted life years from the reduced smoking.

Administration, Cutaneous↗