Therapeutic non adherence: a rational behavior revealing patient preferences ?

This paper offers an indirect measure of patient welfare based on whether patients comply with the prescription they receive. Adherence behavior is supposed to reveal patients' subjective valuations of particular therapies. We write a simple theoretical model of patient adherence behavior, that reflects the trade-off between perceived costs and observed regimen efficacy. A discrete choice framework is then used for the estimation, ie the comparison of the incremental benefit of drug intake between two regimens. Consequently, the empirical analysis is based on the identification of patient and drug characteristics associated with adherence. The econometric approach is implemented through a bivariate panel two-equation simultaneous system studying jointly the factors associated with adherence and response to treatment. The data come from a randomized clinical trial conducted in France between 1999 and 2001 and comparing the efficacy of 2 tritherapy strategies in HIV disease. Both the theoretical and empirical results suggest that, for comparable clinical efficacy and toxicity levels, a higher adherence level is associated with higher patient welfare, thus adding valuable information to conclusions drawn by a mere biostatistical analysis. Therefore, from the perspective of the patient, the adherence-enhancing drug must be favored. Our results based on panel data also stress that unobserved patient characteristics account substantially for drug valuation and that the assessment evolves during the course of the treatment. Furthermore, we provide a new framework for the analysis of adherence data. The microeconometric framework highlights that non adherence is an endogenous behavior, thus suggesting new ways for improving adherence.drug valuation method ; revealed preferences ; endogenous adherence behavior ; panel bivariate probit estimation ; HIV

Incremental willingness to pay: a theoretical and empirical exposition

Applications of willingness to pay (WTP) have shown the difficultly to discriminate between various options. This reflects the problem of embedding in both its specific sense, of options being nested within one another, and its more-general sense, whereby respondents cannot discriminate between close substitutes or between more-disparate rivals for the same budget. Furthermore, high proportions of reversals between WTP-value and simple preference based rankings of options are often highlighted. Although an incremental WTP approach was devised to encourage more differentiated answers and a higher degree of consistency among respondents, a theoretical basis for this approach has not been elucidated, and there is little evidence to show that this approach might indeed achieve greater consistency between explicit and implicit rankings inferred from WTP values.We address both these issues. Following our theoretical exposition, standard and incremental approaches were compared with explicit ranking in a study assessing preferences for different French emergency care services. 280 persons, representative of the French adult population, were interviewed. Half received the incremental version, the other half the standard version. Results suggest that the incremental approach provides a ranking of options fully in line with explicit ranking. The standard approach was reasonably consistent with explicit ranking but proved unable to differentiate between the five most preferred providers, as predicted by theory. Our findings suggest that the incremental approach provides results which can be used in priority-setting contexts

Catastrophic Health ExpenditureandHousehold Well-Being

According to the catastrophic health expenditure methodology a household is in catastrophe if its health out-of-pocket budget share exceeds a critical threshold. We develop a conceptual framework for addressing three questions in relation to this methodology, namely: 1. Can a budget share be informative about the sign of a change in welfare? 2. Is there a positive association between a household's poverty shortfall and its health out-of-pocket budget share? 3. Does an increase in population coverage of a health insurance scheme always result in a reduction of the prevalence of catastrophic expenditures?Catastrophic health expenditure, welfare change, poverty, performanceof health insurance schemes.

Catastrophic Health Expenditure and Household Well-Being

According to the catastrophic health expenditure methodology a house-hold is in catastrophe if its health out-of-pocket budget share exceeds a critical threshold. We develop a conceptual framework for addressing three questions in relation to this methodology, namely: 1. Can a budget share be informative about the sign of a change in welfare? 2. Is there a positive association between a households poverty shortfall and its health out-of-pocket budget share? 3. Does an increase in coverage of a health insurance scheme always result in a reduction of the prevalence of catastrophic ex-penditures?

The influence of supplementary health insurance on switching behaviour : evidence on Swiss data

This paper focuses on the switching behaviour of sickness fund enrollees in the Swiss health insurance system. Even though the new Federal Law on Social Health Insurance (LAMal) was implemented in 1996 to promote competition among health insurers, there still remains large premium variations within cantons. This indicates that competition has not been able so far to lead to a single price, and reveals some inertia among consumers who seem reluctant to switch to less expensive funds. We investigate one possible barrier to switching behaviour, namely the influence of the supplementary insurance on the choice for basic insurance plan in Switzerland, which has not been studied so far. Our aim is to analyse the two decisions (choice of health plan, subscription to supplementary insurance contracts). We use the data of the OFAS survey conducted in 2000 on health plan choice and import some additional data on the sickness funds (number of enrollees, premiums). The decision to switch is estimated by both logit and a fixed-effects logit models; two main explanatory variables are studied: premiums (for basic insurance contracts) and supplementary insurance. The results suggest that holding a supplementary insurance contract substantially decreases the propensity to switch. The switching decision is positively influenced by the expected gain of switching, measured by the premium differential. The expected gain of switching is higher for switchers with no supplementary insurance (CHF 19.44) than for switchers with supplementary insurance (CHF 13.06). The income level has a direct positive influence on the propensity to buy a supplementary insurance. This finding suggests that the purchase of supplementary insurance is influenced, not only by risk aversion, but also by the willingness to pay for the goods covered by the supplementary insurance, which would be higher for rich people. Bad health has a negative influence on the subscription to a supplementary contract, but is no longer significant when the income is introduced into the specification. All the information about health is captured by the income level, a low income being strongly correlated with a bad health status. Income and a supplementary insurance contract are observable by the insurance company, and can be used as tools for selection.Health Insurance, Private Sector

The impact of information on patient preferences in different delivery patterns : a contingent valuation study of prescription versus OTC drugs

Our analysis assessed the impact of information on patients' preferences in prescription vs over-the-counter (OTC) delivery systems. A contingent valuation (CV) study was implemented, randomly assigning 1594 people into the receipt of limited or extended information concerning new influenza drugs. In each information arm, people answered two questions: the first asked about willingness to pay (WTP) for the new prescription drug; the second asked about WTP for the same drug sold OTC. We show that WTP is higher for the OTC scenario and that the level of information plays a significant role in the valuation of the OTC scenario, with more information increasing the WTP. In contrast, the level of information has no impact on WTP for prescription medicine. Thus, for the kind of drug (i.e. safe, not requiring medical supervision) considered here, a switch to OTC status can be expected to be all the more beneficial as the patient is provided with more information concerning the capability of the drug. Conclusions: Our results shed some light on one of the most challenging issues that health policy makers are currently faced with, namely the threat of a bird flu pandemic. Drug delivery is a critical component of pandemic influenza preparedness. Furthermore, the congruence of our results with the agency and demand theories provides an important test of the validity of using WTP based on CV methods.WTP, CV, OTC versus prescription, neuraminidase inhibitors, interval-censored regression

The influence of supplementary health insurance on switching behaviour: evidence on Swiss data

This paper focuses on the switching behaviour of sickness fund enrolees in the Swiss health insurance system. Even though the new Federal Law on Social Health Insurance (LAMal) was implemented in 1996 to promote competition among health insurers in basic insurance, there still remains large premium variations within cantons. This indicates that competition has not been able so far to lead to a single price, and reveals some inertia among consumers who seem reluctant to switch to less expensive funds. We investigate one possible barrier to switching behaviour, namely the influence of the supplementary insurance. Our aim is to analyse two decisions (switching decision in basic insurance, subscription to supplementary insurance contracts). We use survey data on health plan choice and import some market data related to the sickness funds (number of enrollees, premiums). The decision to switch and the decision to subscribe to a supplementary contract are estimated both separately and jointly. The results suggest that holding a supplementary insurance contract substantially decreases the propensity to switch. However the impact of supplementary insurance is not significant when the individual assesses his/her health as "very good" ; to the contrary, holding a supplementary contract significantly reduces the propensity to switch when the indivual's subjective health status deteriorates. Futhermore, the switching decision is positively influenced by the expected gain of switching. In comparison with the range of the premium difference, the limitations to switch due to the supplementary insurance is moderate, though non negligible. As for the decision to subscribe a supplementary contract, the results show that the income level has a direct positive influence on the propensity to buy a supplementary insurance. Our results suggest that a major mechanism is going on in relation to supplementary insurance: holding a supplementary contract might stop individuals from switching when the individual thinks that she/he could be regarded as a bad risk due to the selection practices that are allowed in supplementary insurance markets. This result bears major policy implications concerning the regulation of basic and supplementary insurance markets.competition in health insurance ; switching behaviour ; premium convergence ; influence of supplementary insurance

The Effect of Hours of Work on Social Interaction

Over time, increases in hours of work per capita have created the intuitively plausible notion that there is less time available to pursue social interactions. The specific question addressed in this paper is the effect of hours of work on social interaction. This is a difficult empirical question since omitted factors could increase both hours of work and social interaction. The approach taken in this paper utilizes an exogenous decline in hours of work in France due to a new employment law. The results clearly show that the employment law reduced hours of work but there is no evidence that the extra hours went to increased social interactions. Although hours of work are not an important determinant of social interaction, human capital is found to be important. The effect of human capital, as measured by education and age, is positive for membership groups but negative for visiting relatives and friends. Also, contrary to expectations, there are no important differences in the determinants of social interaction by gender, marital status or parent status. Finally, a comparison between France and the US show that the response to human capital and other variables are much the same in both nations.

Choice, Price Competition and Complexity in Markets for Health Insurance

The United States and other nations rely on consumer choice and price competition among competing health plans to allocate resources in the health sector. A great deal of research has examined the efficiency consequences of adverse selection in health insurance markets, less attention has been devoted to other aspects of consumer choice. The nation of Switzerland offers a unique opportunity to study price competition in health insurance markets. Switzerland regulates health insurance markets with the aim of minimizing adverse selection and encouraging strong price competition. We examine consumer responses to price differences in local markets and the degree of price variation in local markets. Using both survey data and observations on local markets we obtain evidence suggesting that as the number of choices offered to individuals grow their willingness to switch plans given a set of price dispersion differences declines allowing large price differences for relatively homogeneous products to persist. We consider explanations for this phenomenon from economics and psychology.