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PubMed1996

Introduction of a new laboratory test: an econometric approach with the use of neural network analysis.

We designed a simulation model for the assessment of the financial risks involved when a new diagnostic test is introduced in the laboratory. The model is based on a neural network consisting of ten neurons and assumes that input entities can have assigned appropriate uncertainty. Simulations are done on a 1-day interval basis. Risk analysis completes the model and the financial effects are evaluated for a selected time period. The basic output of the simulation consists of total expenses and income during the simulation time, net present value of the project at the end of simulation, total number of control samples during simulation, total number of patients evaluated and total number of used kits.

Chemistry, Clinical↗
PubMed1994

Remodeling health care.

Standard models of patient demand for health care and health care suppliers' response to that demand imply that some manner of manipulation of the prices faced by patients must be chief among the mechanisms of systemic cost control. However convenient econometrically, these standard models cannot reflect the complexity of patient demand behavior, and they say little about the predominant causes of health-care cost escalation. This paper describes a richer Jevonian political-economic model that sensibly portrays patient demand and physician and corporate supply behaviors and suggests a range of cost-controlling and care-enhancing compensatory steps, some professional, some societal. This new model implies that reformers in the United States could take respectful advantage of the fundamentally self-regulating nature of patient demand for health care by shifting their attention away from its further discouragement and toward the modulation of other factors.

Cost Sharing↗
PubMed2003

Is cannabis a stepping-stone for cocaine?

This paper uses a unique dataset on the inhabitants of Amsterdam, to study the dynamics of the consumption of cannabis and cocaine. People are most likely to start using that drugs at ages 18-20 and 20-25. An analysis of the starting rates shows some evidence of cannabis being a "stepping-stone" for cocaine. However, the fact that some individuals use both cannabis and cocaine has to do mostly with correlation through (unobserved) personal characteristics and not with cannabis causing the use of cocaine.

Adolescent↗
PubMed2000

Health care expenditure inertia in the OECD countries: a heterogeneous analysis.

Health care expenditure studies of the Organization for Economic Cooperation and Development (OECD) countries remain important because their findings often suggest cost containment and other policy initiatives. This paper focuses on the compatibility of OECD health data with the "expenditure inertia" (or lagged adjustments) hypothesis, by modeling individual country time-series data of 21 nations for the 1960-1993 period. Maximum likelihood estimates of the Box-Cox transformation regression models reveal that: (a) the hypothesized impact of health "expenditure inertia" is both pervasive and strong, averaging 0.64 across the countries; (b) the real GDP elasticities of health care expenditures vary widely among the countries and average 0.34 in the short run--implying that health care is a necessity; (c) the long run GDP elasticities are less than 1 in 8 countries, unitary elastic in 8 countries and elastic in 5 countries--suggesting that health care is not universally a necessity or a luxury commodity for the OECD countries; (d) physician-inducement effects (dis-inducement in a few countries) are weak, with a mean elasticity estimate of 0.17; and (e) no unique functional form approximation model is globally compatible with the data across the countries. Health care cost containment policy implications of these findings are explored.

Benchmarking↗
PubMed2006

The utility of extended longitudinal profiles in predicting future health care expenditures.

BACKGROUND: Health care spending is highly concentrated. Prediction models that accurately identify the characteristics of individuals most likely to incur high levels of health expenditures in a subsequent year are important analytical and statistical tools. OBJECTIVES: This study examined the capacity of alternative models to predict the likelihood of incurring high levels of medical expenditures in a subsequent year. This effort also evaluated the utility of an additional year of longitudinal information. SUBJECTS: A nationally representative sample from the Medical Expenditure Panel Survey (MEPS). METHODS: The MEPS longitudinal data are used to examine the persistence of high expenditures during a 2-year period. With the unique linkage of the MEPS to the National Health Interview Survey, the utility of an additional year of data also was examined. Resultant models were evaluated in terms of sensitivity, specificity, and predictive capacity. RESULTS: Only modest marginal gains in discrimination capacity were realized from the use of extended longitudinal profiles from the National Health Interview Survey, relative to information on prior year characteristics. CONCLUSIONS: Our results highlight the continuing concentration of health care expenditures during the period 1996 to 2002 and reveal some attenuation in magnitude in the tail of this distribution over time. Further, our results provide evidence of the utility of probabilistic models as prediction tools to identify individuals likely to incur high levels of expenditures in future years. Predictive capacity does not suffer when restricted to a single year of prior information.

Adolescent↗
PubMedDate not supplied

Transitions from AFDC to SSI before welfare reform.

The Supplemental Security Income (SSI) and Aid to Families with Dependent Children (AFDC) programs serve populations with similar characteristics. SSI serves adults and children with disabilities who are in low-income families, and AFDC serves low-income families with children. Because of that overlap, policy changes in one program can affect the other. In 1996, Congress enacted the Personal Responsibility and Work Opportunity Reconciliation Act, which transformed AFDC into the Temporary Assistance for Needy Families (TANF) program. Many people have expected that implementing that welfare reform legislation would eventually increase SSI participation, for two reasons. First, TANF includes new work requirements and time limits that induce more AFDC/TANF recipients with disabilities to obtain SSI benefits. Second, the change in the funding mechanism--from open-ended funding on a matching basis for AFDC to cash assistance block grants for TANF--gives states a stronger incentive to shift welfare recipients to SSI. This article examines the interaction between the SSI and AFDC programs in the prereform period (1990 to 1996) and discusses the potential implications of welfare reform on that interaction. Using matched data from the Survey of Income and Program Participation and Social Security Administration (SSA) records, our analysis focuses on how the interaction of those programs affects young women (aged 18 to 40) and children (aged 0 to 17). We find a very strong link between AFDC and SSI for young women and children. Significant portions of young female and child SSI beneficiaries in the 1990-1993 period were in AFDC families or had received AFDC in the past. In addition, a substantial share of young women and children who received AFDC during that period eventually entered SSI. Because the SSI program is now serving a much larger population of families with young women and children than in the past, SSA might need to develop policies to better serve that group. The findings also suggest that the prereform period is a poor baseline against which to measure the impact of TANF, primarily because of the instability in programs and policies.

Adolescent↗
PubMed2005

Income inequality, poverty, and population health: evidence from recent data for the United States.

In this study, state-level US data for the years 2000 and 1990 are used to provide additional evidence on the roles of income inequality and poverty in population health. Five main points are noted. First, contrary to the suggestion made in several recent studies, the income inequality parameter is observed to be quite robust and carries statistical significance in mortality equations estimated from several observation sets and a fairly wide variety of specificational choices. Second, the evidence does not indicate that significance of income inequality is lost when education variables are included. Third, similarly, the income inequality parameter shows significance when a race variable is added, and also when both race and urbanization terms are entered. Fourth, while poverty is seen to have some mortality-increasing consequence, the role of income inequality appears stronger. Fifth, income inequality retains statistical significance when a quadratic income term is added and also if the log-log version of a fairly inclusive model is estimated. I therefore suggest that the recent skepticism articulated by several scholars in regard to the robustness of the income inequality parameters in mortality equations estimated from the US data should be reconsidered.

Educational Status↗
PubMed2000

Initial treatment choice in depression: impact on medical expenditures.

OBJECTIVE: The purpose of this study was to examine the economic outcomes associated with initial treatment choice following a diagnosis of depression. METHODS: Insurance claims data were used to classify patients into one of 4 treatment cohorts: no therapy, psychotherapy, drug therapy and combination therapy. Potential sample selection bias was accounted for by using a 2-stage econometric estimation procedure where initial treatment choice was estimated using a multinomial logistic regression model in the first stage, and total and mental healthcare costs were estimated in ordinary least squares regression models in the second stage. Log predicted costs from the second stage were compared to determine the relative costs associated with each cohort. RESULTS: Significant differences (p < 0.008) in total costs were found between the combination therapy (log predicted cost = 9.526) and psychotherapy cohorts (log predicted cost = 8.120) in the analysis that included all observations (n = 9110). In the analysis that included patients who initiated therapy with a non-mental health provider (n = 2673), the drug therapy cohort (log predicted cost = 8.238) was found to be significantly more costly as compared to the no therapy cohort (log predicted cost = 7.788). CONCLUSIONS: These results indicate that after controlling for both observed and unobserved factors, total healthcare costs may be higher in patients who initiate therapy with drug therapy and combination therapy as opposed to no therapy or psychotherapy. In addition, the finding that patients initially receiving psychotherapy alone tend to have higher mental healthcare costs but lower total healthcare costs than other patients may indicate that psychotherapy has an impact on comorbid illness and may subsequently reduce total healthcare costs.

Antidepressive Agents↗
PubMed2002

How important are tobacco prices in the propensity to start and quit smoking? An analysis of smoking histories from the Spanish National Health Survey.

This paper presents an econometric analysis of the effect of policy instruments such as prices, restrictions to use and health warnings on the decisions to start and quit smoking. The duration up to starting and up to quitting is represented with several parametric models for the hazard function, and statistical tests are used to choose the best specification. The estimates reveal that prices have a very weak effect on the duration up to starting. On the contrary, the duration up to quitting is shortened by increases in the prices of the cheapest varieties of cigarettes in the Spanish market. This evidence suggests specific directions for change in the structure of tobacco taxes.

Adolescent↗
PubMed2000

Willingness to pay for improved respiratory and cardiovascular health: a multiple-format, stated-preference approach.

This study uses stated-preference (SP) analysis to measure willingness to pay (WTP) to reduce acute episodes of respiratory and cardiovascular ill health. The SP survey employs a modified version of the health state descriptions used in the Quality of Well Being (QWB) Index. The four health state attributes are symptom, episode duration, activity restrictions and cost. Preferences are elicited using two different SP formats: graded-pair and discrete-choice. The different formats cause subjects to focus on different evaluation strategies. Combining two elicitation formats yields more valid and robust estimates than using only one approach. Estimates of indirect utility function parameters are obtained using advanced panel econometrics for each format separately and jointly. Socio-economic differences in health preferences are modelled by allowing the marginal utility of money relative to health attributes to vary across respondents. Because the joint model captures the combined preference information provided by both elicitation formats, these model estimates are used to calculate WTP. The results demonstrate the feasibility of estimating meaningful WTP values for policy-relevant respiratory and cardiac symptoms, even from subjects who never have personally experienced these conditions. Furthermore, because WTP estimates are for individual components of health improvements, estimates can be aggregated in various ways depending upon policy needs. Thus, using generic health attributes facilitates transferring WTP estimates for benefit-cost analysis of a variety of potential health interventions.

Activities of Daily Living↗
PubMed2004

A flexible approach for estimating the effects of covariates on health expenditures.

Our estimation strategy uses sequences of conditional probability functions, similar to those used in discrete time hazard rate analyses, to construct a discrete approximation to the density function of an outcome of interest conditional on exogenous explanatory variables. Once the conditional density function has been constructed, we can examine expectations of arbitrary functions of the outcome of interest and evaluate how these expectations vary with observed exogenous covariates. We demonstrate the features and precision of the conditional density estimation method (and compare it to other commonly used methods) through Monte Carlo experiments and an application to health expenditures using the RAND Health Insurance Experiment data. Overall, we find that the approximate conditional density estimator provides accurate and precise estimates of derivatives of expected outcomes for a wide range of types of explanatory variables.

Adult↗
PubMed2003

The demand for physician services. Evidence from a natural experiment.

This study exploits a natural experiment in Belgium to estimate the effect of copayment increases on the demand for physician services. It shows how a differences-in-differences (DD) estimator of the price effects can be decomposed into effects induced by the common average proportional price increase (income effects) and by the change in relative prices (substitution effects). The price elasticity of a uniform proportional price increase is relatively small (-0.13 for men and -0.03 for women). Substitution effects are large, especially for women, but imprecisely estimated. Despite the substantial price increases, the efficiency gain of the reform, if any, is modest.

Adult↗
PubMed2003

Optimal commodity taxation with moral hazard and unobservable outcomes.

The optimal public insurance-taxation scheme is derived for a model with unobservable outcomes. If the government can only observe aggregate commodity expenditures, reimbursement insurance is constrained-efficient. However, two distortions accompany the reimbursement scheme. First, consumers are induced to take (forego) actions which increase (decrease) the likelihood of adverse outcomes (i.e., ex ante moral hazard). Second, reimbursement insurance creates a subsidy distortion (i.e., ex post moral hazard). Ex ante moral hazard calls for taxation (subsidization) of commodities which increase (decrease) the probability of adverse outcomes. The second distortion calls for taxation (subsidization) of commodities which are sufficiently strong complements to (substitutes for) the insured commodity. An example centered on cigarettes and medical insurance is presented.

Fees and Charges↗
PubMedDate not supplied

Cost-effectiveness of antiplatelet agents in secondary stroke prevention: the limits of certainty.

UNLABELLED: Which of the available antiplatelet therapies should be preferred for secondary prevention of recurrent ischemic stroke has been contentious. OBJECTIVE: We applied the Duke Stroke Policy Model (DSPM) to reconsider this issue, paying particular attention to the degree of uncertainty in the estimates of their efficacy. The DSPM is a continuous-time simulation model of stroke development and outcome. METHODS: We modified the inputs to reflect the cost of the drugs aspirin (ASA), extended release dipyridamole/aspirin (DP/A) and clopidogrel (CLO), as well as their relative risk in preventing subsequent ischemic stroke in comparison with placebo (PBO). These relative risks were derived from published reports from the second European Stroke Prevention Study (ESPS-2) and Clopidogrel Versus Aspiring in Patients at Risk of Ischemic Events studies. Precision was addressed by applying bootstrapping to the above estimates of relative risk. The target population was 70-year-old men with nondisabling stroke. The outcome measures were quality-adjusted life-years (QALYs), costs, and costs per QALY. RESULTS: Results of Base Case Analysis: In large part because of its modest drug cost, ASA was cost-effective in comparison with PBO. DP/A tended to have improved outcomes, but at increased costs. CLO was dominated in the base case. RESULTS OF SENSITIVITY ANALYSIS: ASA and DP/A cannot be differentiated on a statistical basis alone. In probabilistic sensitivity analysis, CLO was rarely preferred. CONCLUSIONS: Either DP/A or ASA appear to be a good value in comparison with no treatment, but there is no clear winner between the two. In the absence of a definitive randomized trial, simulation modeling can help clarify the trade-offs between the various antiplatelet agents, but not beyond the constraints imposed by the imprecision in the estimates that can be obtained from the current evidence base.

Aged↗
PubMedDate not supplied

Developing better economic models of osteoporosis: considerations for the calculation of the relative risk of fracture.

OBJECTIVE: Simulation models are often used to assess cost-effectiveness of osteoporosis therapies. Many cost-effectiveness analyses are interested in a subset of the general population, such as high-risk patients. As the analyses are very sensitive to the assumed risk of fracture, it is imperative that the rates accurately reflect the fracture risk in the specified target population. The objective of this study was to describe the methodological difficulties and present some possible solutions for calculating the risk of fracture in target populations of interest. METHODS: For binary risk factors, a method for converting from a relative risk (RR) for people with a risk factor relative to those without, to an RR in the target population compared with the general population, is described. For continuous risk factors (i.e., bone mineral density [BMD]), data are often provided as an RR of fracture per SD decrease. A method for converting from an RR per SD decrease to an RR in those below a certain BMD threshold, compared with the general population, is presented. RESULTS: These results should allow future economic models to more accurately incorporate existing knowledge of risk factors by introducing methods to calculate fracture risk estimates in a target population. CONCLUSION: It illustrates the importance of considering the prevalence of risk factors in the general population when calculating RR in a target population.

Aged↗