http://repub.eur.nl/res/aut/16337/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/39641/ 2013-04-01T00:00:00Z Life expectancy continues to grow in most Western countries; however, a major remaining question is whether longer life expectancy will be associated with more or fewer life years spent with poor health. Therefore, complementing forecasts of life expectancy with forecasts of health expectancies is useful. To forecast health expectancy, an extension of the stochastic extrapolative models developed for forecasting total life expectancy could be applied, but instead of projecting total mortality and using regular life tables, one could project transition probabilities between health states simultaneously and use multistate life table methods. In this article, we present a theoretical framework for a multistate life table model in which the transition probabilities depend on age and calendar time. The goal of our study is to describe a model that projects transition probabilities by the Lee-Carter method, and to illustrate how it can be used to forecast future health expectancy with prediction intervals around the estimates. We applied the method to data on the Dutch population aged 55 and older, and projected transition probabilities until 2030 to obtain forecasts of life expectancy, disability-free life expectancy, and probability of compression of disability. © 2012 Population Association of America. http://repub.eur.nl/res/pub/38588/ 2013-01-01T00:00:00Z The Dutch risk equalization scheme has been improved over the years by including health related risk adjusters. The purpose of the Dutch risk equalization scheme is to prevent risk selection and to correct for predictable losses and gains for insurers. The objective of this paper is to explore the financial incentives for risk selection under the Dutch risk equalization scheme. We used a simulation model to estimate lifetime health care costs and risk equalization contributions for three cohorts (a smoking; an obese; and a healthy living cohort). Financial differences for the three cohorts were assessed by subtracting health care costs from risk equalization contributions. Even under an elaborate risk equalization system, the healthy living cohort was still most financially attractive for insurers. Smokers were somewhat less attractive, while the obese cohort was least attractive. Lifetime differences with healthy living individuals (revenues minus costs) were modest: €4840 for obese individuals and €1101 for smokers. Under a simple form of risk equalization these differences were higher, €8542 and €4620 respectively. Improvement of the risk equalization scheme reduced the gap between costs and revenues. Incentives for undesirable risk selection were reduced, but simultaneously incentives for health promotion were weakened. This highlights a new prevention paradox: improving the level playing field for health insurers will inevitably limit their incentives for promoting the health of their clients. http://repub.eur.nl/res/pub/37322/ 2012-12-01T00:00:00Z Although the effect of time to death (TTD) on health care expenditures (HCE) has been investigated using individual level data, the most profound implications of TTD have been for the forecasting of macro-level HCE. Here we estimate the TTD model using macro-level data from the Netherlands consisting of mortality rates and age- and gender-specific per capita health expenditures for the years 1981-2007. Forecasts for the years 2008-2020 of this macro-level TTD model were compared to forecasts that excluded TTD. Results revealed that the effect of TTD on HCE in our macro model was similar to those found in micro-econometric studies. As the inclusion of TTD pushed growth rate estimates from unidentified causes upwards, however, the two models' forecasts of HCE for the 2008-2020 were similar. We argue that including TTD, if modeled correctly, does not lower forecasts of HCE. http://repub.eur.nl/res/pub/38889/ 2012-11-20T00:00:00Z In Health Impact Assessment (HIA), or priority-setting for health policy, effects of risk factors (exposures) on health need to be modeled, such as with a Markov model, in which exposure influences mortality and disease incidence rates. Because many risk factors are related to a variety of chronic diseases, these Markov models potentially contain a large number of states (risk factor and disease combinations), providing a challenge both technically (keeping down execution time and memory use) and practically (estimating the model parameters and retaining transparency). To meet this challenge, we propose an approach that combines micro-simulation of the exposure information with macro-simulation of the diseases and survival. This approach allows users to simulate exposure in detail while avoiding the need for large simulated populations because of the relative rareness of chronic disease events. Further efficiency is gained by splitting the disease state space into smaller spaces, each of which contains a cluster of diseases that is independent of the other clusters. The challenge of feasible input data requirements is met by including parameter calculation routines, which use marginal population data to estimate the transitions between states. As an illustration, we present the recently developed model DYNAMO-HIA (DYNAMIC MODEL for Health Impact Assessment) that implements this approach. http://repub.eur.nl/res/pub/38680/ 2012-09-24T00:00:00Z Background: Counseling in combination with pedometer use has proven to be effective in increasing physical activity and improving health outcomes. We investigated the cost-effectiveness of this intervention targeted at one million insufficiently active adults who visit their general practitioner in the Netherlands.Methods: We used the RIVM chronic disease model to estimate the long-term effects of increased physical activity on the future health care costs and quality adjusted life years (QALY) gained, from a health care perspective.Results: The intervention resulted in almost 6000 people shifting to more favorable physical-activity levels, and in 5100 life years and 6100 QALYs gained, at an additional total cost of EUR 67.6 million. The incremental cost-effectiveness ratio (ICER) was EUR 13,200 per life year gained and EUR 11,100 per QALY gained. The intervention has a probability of 0.66 to be cost-effective if a QALY gained is valued at the Dutch informal threshold for cost-effectiveness of preventive intervention of EUR 20,000. A sensitivity analysis showed substantial uncertainty of ICER values.Conclusion: Counseling in combination with pedometer use aiming to increase physical activity may be a cost-effective intervention. However, the intervention only yields relatively small health benefits in the Netherlands. http://repub.eur.nl/res/pub/34965/ 2012-08-22T00:00:00Z In this paper, we report a case study on a technical generalization of the Lee-Carter model, originally developed to project mortality, to forecast body mass index (BMI, kg/m2). We present the method on an annually repeated cross-sectional data set, the Dutch Health Survey, covering years between 1981 and 2008. We applied generalized additive models for location, scale and shape semi-parametric regression models to estimate the probability distribution of BMI for each combination of age, gender and year assuming that BMI follows a Box-Cox power exponential distribution. We modelled and extrapolated the distribution parameters as a function of age and calendar time using the Lee-Carter model. The projected parameters defined future BMI distributions from which we derived the prevalence of normal weight, overweight and obesity. Our analysis showed that important changes occurred not only in the location and scale of the BMI distribution but also in the shape of it. The BMI distribution became flatter and more shifted to the right. Assuming that past trends in the distribution of BMI will continue in the future, we predicted a stable or slow increase in the prevalence of overweight until 2020 among men and women. We conclude that our adaptation of the Lee-Carter model provides an insightful and flexible way of forecasting BMI and that ignoring changes in the shape of the BMI distribution would likely result in biased forecasts. http://repub.eur.nl/res/pub/34966/ 2012-08-01T00:00:00Z http://repub.eur.nl/res/pub/37874/ 2012-03-15T00:00:00Z A problem occurring in chronic disease modeling is the estimation of transition probabilities of moving from one state of a categorical risk factor to another. Transitions could be obtained from a cohort study, but often such data may not be available. However, under the assumption that transitions remain stable over time, age specific cross-sectional prevalence data could be used instead. Problems that then arise are parameter identifiability and the fact that age dependent cross-sectional data are often noisy or are given in age intervals. In this paper we propose a method to estimate so-called net annual transition probabilities from cross-sectional data, including their uncertainties. Net transitions only describe the net inflow or outflow into a certain risk factor state at a certain age. Our approach consists of two steps: first, smooth the data using multinomial P-splines, second, from these data estimate net transition probabilities. This second step can be formulated as a transportation problem, which is solved using the simplex algorithm from linear programming theory. A sensible specification of the cost matrix is crucial to get meaningful results. Uncertainties are assessed by parametric bootstrapping. We illustrate our method using data on body mass index. We conclude that this method provides a flexible way of estimating net transitions and that the use of net transitions has implications for model dynamics, for example when modeling interventions. http://repub.eur.nl/res/pub/33096/ 2012-01-01T00:00:00Z Objective: The impact population aging exerts on future levels of long-term care (LTC) spending is an urgent topic in which few studies have accounted for disability trends. We forecast individual lifetime and population aggregate annual LTC spending for the Dutch 55+ population to 2030 accounting for changing disability patterns. Methods: Three levels of (dis)ability were distinguished: none, mild, and severe. Two-part models were used to estimate LTC spending as a function of age, sex, and disability status. A multistate life table model was used to forecast age-specific prevalence of disability and life expectancy (LE) in each disability state. Finally, 2-part model estimates and multistate projections were combined to obtain forecasts of LTC expenditures. Results: LE is expected to increase, whereas life years in severe disability remain constant, resulting in a relative compression of severe disability. Mild disability life years increase, especially for women. Lifetime homecare spending—mainly determined by mild disability—increases, whereas institutional spending remains fairly constant due to stable LE with severe disability. Lifetime LTC expenditures, largely determined by institutional spending, are thus hardly influenced by increasing LE. Aggregate spending for the 55+ population is expected to rise by 56.0% in the period of 2007–2030. Conclusions: Longevity gains accompanied by a compression of severe disability will not seriously increase lifetime spending. The growth of the elderly cohort, however, will considerably increase aggregate spending. Stimulating a compression of disability is among the main solutions to alleviate the consequences of longevity gains and population aging to growth of LTC spending. http://repub.eur.nl/res/pub/31055/ 2011-09-01T00:00:00Z Background: The high prevalence of chronic diseases in Western countries implies that the presence of multiple chronic diseases within one person is common. Especially at older ages, when the likelihood of having a chronic disease increases, the co-occurrence of distinct diseases will be encountered more frequently. The aim of this study was to estimate the age-specific prevalence of multimorbidity in the general population. In particular, we investigate to what extent specific pairs of diseases cluster within people and how this deviates from what is to be expected under the assumption of the independent occurrence of diseases (i.e., sheer coincidence).Methods: We used data from a Dutch health survey to estimate the prevalence of pairs of chronic diseases specified by age. Diseases we focused on were diabetes, myocardial infarction, stroke, and cancer. Multinomial P-splines were fitted to the data to model the relation between age and disease status (single versus two diseases). To assess to what extent co-occurrence cannot be explained by independent occurrence, we estimated observed/expected co-occurrence ratios using predictions of the fitted regression models.Results: Prevalence increased with age for all disease pairs. For all disease pairs, prevalence at most ages was much higher than is to be expected on the basis of coincidence. Observed/expected ratios of disease combinations decreased with age.Conclusion: Common chronic diseases co-occur in one individual more frequently than is due to chance. In monitoring the occurrence of diseases among the population at large, such multimorbidity is insufficiently taken into account. http://repub.eur.nl/res/pub/31194/ 2011-08-15T00:00:00Z Background: Depression causes a large burden of disease worldwide. Effective prevention has the potential to reduce that burden considerably. This study aimed to investigate the cost-effectiveness of minimal contact psychotherapy, based on Lewinsohn's 'Coping with depression' course, targeted at opportunistically screened individuals with sub-threshold depression. Methods and Results: Using a Markov model, future health effects and costs of an intervention scenario and a current practice scenario were estimated. The time horizon was five years. Incremental cost-effectiveness ratios were expressed in euro per Disability Adjusted Life Year (DALY) averted. Probabilistic sensitivity analysis was employed to study the effect of uncertainty in the model parameters. From the health care perspective the incremental cost-effectiveness ratio was € 1,400 per DALY, and from the societal perspective the intervention was cost-saving. Although the estimated incremental costs and effects were surrounded with large uncertainty, given a willingness to pay of € 20,000 per DALY, the probability that the intervention is cost-effective was around 80%. Conclusion: This modelling study showed that opportunistic screening in primary care for sub-threshold depression in combination with minimal contact psychotherapy may be cost-effective in the prevention of major depression. http://repub.eur.nl/res/pub/24050/ 2011-06-23T00:00:00Z Background: The validity, reliability and cross-country comparability of summary measures of population health (SMPH) have been persistently debated. In this debate, the measurement and valuation of nonfatal health outcomes have been defined as key issues. Our goal was to quantify and decompose international differences in health expectancy based on health-related quality of life (HRQoL). We focused on the impact of value set choice on cross-country variation. Methods: We calculated Quality Adjusted Life Expectancy (QALE) at age 20 for 15 countries in which EQ-5D population surveys had been conducted. We applied the Sullivan approach to combine the EQ-5D based HRQoL data with life tables from the Human Mortality Database. Mean HRQoL by country-gender-age was estimated using a parametric model. We used nonparametric bootstrap techniques to compute confidence intervals. QALE was then compared across the six country-specific time trade-off value sets that were available. Finally, three counterfactual estimates were generated in order to assess the contribution of mortality, health states and health-state values to cross-country differences in QALE. Results: QALE at age 20 ranged from 33 years in Armenia to almost 61 years in Japan, using the UK value set. The value sets of the other five countries generated different estimates, up to seven years higher. The relative impact of choosing a different value set differed across country-gender strata between 2% and 20%. In 50% of the country-gender strata the ranking changed by two or more positions across value sets. The decomposition demonstrated a varying impact of health states, health-state values, and mortality on QALE differences across countries. Conclusions: The choice of the value set in SMPH may seriously affect cross-country comparisons of health expectancy, even across populations of similar levels of wealth and education. In our opinion, it is essential to get more insight into the drivers of differences in health-state values across populations. This will enhance the usefulness of health-expectancy measures. http://repub.eur.nl/res/pub/26373/ 2011-05-23T00:00:00Z http://repub.eur.nl/res/pub/23183/ 2011-04-01T00:00:00Z It has been demonstrated repeatedly that time to death is a much better predictor of health care expenditures than age. This is known as the ‘red herring’ hypothesis. In this article, we investigate whether this is also the case regarding disease-specific hospital expenditures. Longitudinal data samples from the Dutch hospital register (n511 253 455) were used to estimate 94 disease-specific two-part models. Based on these models, Monte Carlo simulations were used to assess the predictive value of proximity to death and age on disease-specific expenditures. Results revealed that there was a clear effect of proximity of death on health care expenditures. This effect was present for most diseases and was strongest for most cancers. However, even for some less fatal diseases, proximity to death was found to be an important predictor of expenditures. Controlling for proximity to death, age was found to be a significant predictor of expenditures for most diseases. However, its impact is modest when compared to proximity to death. Considering the large variation in the degree to which proximity to death and age matter for each specific disease, we may speak not only of age as a ‘red herring’ but also of a ‘carpaccio of red herrings’. http://repub.eur.nl/res/pub/25581/ 2011-04-01T00:00:00Z AimsMortality attributed to a disease is an important public health measure of the 'burden' of that disease. A discrepancy has been noted between the high mortality rates associated with heart failure (HF) and the share of deaths ascribed to HF in official mortality statistics. It was our main aim to estimate excess mortality associated with HF and use the estimates to better understand the burden of HF.Methods and resultsExcess mortality was defined as the difference in mortality rates between individuals with and those without HF. An epidemiological model was formulated that allowed deriving age-specific excess mortality rates in HF patients from HF incidence and prevalence. Incidence and prevalence were estimated from yearly collected cross-sectional data from four nationally representative General Practice registries in the Netherlands. The year 2007 was chosen as a reference. Next, excess mortality rates were used to calculate numbers of deaths among HF patients and compare the figures with national cause-of-death statistics. The latter were found to be more than three times smaller than the former (roughly 6000 vs. 21 000). Further, by applying HF prevalence and mortality rates to a life table of the Dutch population, average numbers of life years lost due to HF were calculated to be 6.9 years.ConclusionNational mortality statistics strongly underestimate the number of deaths associated with HF. Moreover, the high mortality rate in HF patients amounts to a remarkably large number of life years lost given the advanced age of disease onset. http://repub.eur.nl/res/pub/25523/ 2011-03-17T00:00:00Z Background: Estimates of disease incidence and prevalence are core indicators of public health. The manner in which these indicators stand out against each other provide guidance as to which diseases are most common and what health problems deserve priority. Our aim was to investigate how routinely collected data from different general practitioner registration networks (GPRNs) can be combined to estimate incidence and prevalence of chronic diseases and to explore the role of uncertainty when comparing diseases. Methods. Incidence and prevalence counts, specified by gender and age, of 18 chronic diseases from 5 GPRNs in the Netherlands from the year 2007 were used as input. Generalized linear mixed models were fitted with the GPRN identifier acting as random intercept, and age and gender as explanatory variables. Using predictions of the regression models we estimated the incidence and prevalence for 18 chronic diseases and calculated a stochastic ranking of diseases in terms of incidence and prevalence per 1,000. Results: Incidence was highest for coronary heart disease and prevalence was highest for diabetes if we looked at the point estimates. The between GPRN variance in general was higher for incidence than for prevalence. Since uncertainty intervals were wide for some diseases and overlapped, the ranking of diseases was subject to uncertainty. For incidence shifts in rank of up to twelve positions were observed. For prevalence, most diseases shifted maximally three or four places in rank. Conclusion: Estimates of incidence and prevalence can be obtained by combining data from GPRNs. Uncertainty in the estimates of absolute figures may lead to different rankings of diseases and, hence, should be taken into consideration when comparing disease incidences and prevalences. http://repub.eur.nl/res/pub/23204/ 2010-09-01T00:00:00Z Abstract Prevention of unhealthy lifestyles has sometimes been promoted as simultaneously reducing costs and improving public health but this will unlikely prove to be true. Additional medical costs in life years gained due to treatment of unrelated diseases may offset possible savings in related diseases, but are often ignored both in health promotion policies and in economic evaluations of life-prolonging interventions. Many national guidelines explicitly recommend excluding these costs from economic evaluations or leave inclusion up to the discretion of the analyst. This may result in too favorable estimations of cost-effectiveness, feeding the unjustified optimism among policymakers regarding lifestyle interventions as a cost-saving option. However, prevention may still be a cost-effective way to improve public health, even when it does not result in cost savings, but this should be judged taking all future costs into account and be based on the true value for money provided by lifestyle interventions. http://repub.eur.nl/res/pub/23202/ 2010-05-01T00:00:00Z http://repub.eur.nl/res/pub/23169/ 2010-04-01T00:00:00Z Abstract: The inclusion of medical costs in life years gained in economic evaluations of health care technologies has long been controversial. Arguments in favour of the inclusion of such costs are gaining support, which shifts the question from whether to how to include these costs. This paper elaborates on the issue how to include cost in life years gained in cost effectiveness analysis given the current practice of economic evaluations in which costs of related diseases are included. We combine insights from the theoretical literature on the inclusion of unrelated medical costs in life years gained with insights from the so-called 'red herring' literature. It is argued that for most interventions it would be incorrect to simply add all medical costs in life years gained to an ICER, even when these are corrected for postponement of the expensive last year of life. This is the case since some of the postponement mechanism is already captured in the unadjusted ICER by modelling the costs of related diseases. Using the example of smoking cessation, we illustrate the differences and similarities between different approaches. The paper concludes with a discussion about the proper way to account for medical costs in life years gained in economic evaluations. http://repub.eur.nl/res/pub/23172/ 2010-03-01T00:00:00Z Inleiding: Als iemand dankzij een preventieve of curatieve interventie langer leeft is het zeer waarschijnlijk dat deze persoon in zijn of haar extra levensjaren medische zorg consumeert. Neem als voorbeeld Jan die op 60-jarige leeftijd een succesvolle harttransplantatie heeft ondergaan. Dankzij de harttransplantatie sterft Jan niet in zijn 60ste levensjaar maar in zijn 75ste levensjaar en in deze 15 extra levensjaren zal Jan medische zorg consumeren. Deze medische zorg in gewonnen levensjaren wordt in de vakliteratuur vaak aangeduid met de term ‘indirecte medische kosten’. In een binnenkort te verschijnen artikel in het blad Health Economics hebben we gepoogd de theoretische discussie rondom indirecte medische kosten in het licht te zetten van de empirische literatuur rondom de kosten van vergrijzing en de huidige praktijk van economische evaluaties. In dit stuk wordt alvast een voorproefje op dat artikel gegeven. http://repub.eur.nl/res/pub/23223/ 2010-01-01T00:00:00Z http://repub.eur.nl/res/pub/14252/ 2008-12-01T00:00:00Z In a recent article in this journal Lee argued that indirect medical costs should be ignored in economic evaluations. To reach this conclusion, Lee uses an unrealistic and uncommon budget constraint. This comment highlights a number of methodological problems in Lee's analysis. Moreover, it highlights that looking at current practice of economic evaluation, Lee's model implies the inclusion rather than the exclusion of indirect medical costs. http://repub.eur.nl/res/pub/14817/ 2008-09-23T00:00:00Z Which costs and benefits to consider in economic evaluations of healthcare interventions remains an area of much controversy. Unrelated medical costs in life-years gained is an important cost category that is normally ignored in economic evaluations, irrespective of the perspective chosen for the analysis. National guidelines for pharmacoeconomic research largely endorse this practice, either by explicitly requiring researchers to exclude these costs from the analysis or by leaving inclusion or exclusion up to the discretion of the analyst. However, the inclusion of unrelated medical costs in life-years gained appears to be gaining support in the literature. This article provides an overview of the discussions to date. The inclusion of unrelated medical costs in life-years gained seems warranted, in terms of both optimality and internal and external consistency. We use an example of a smoking-cessation intervention to highlight the consequences of different practices of accounting for costs and effects in economic evaluations. Only inclusion of all costs and effects of unrelated medical care in life-years gained can be considered both internally and externally consistent. Including or excluding unrelated future medical costs may have important distributional consequences, especially for interventions that substantially increase length of life. Regarding practical objections against inclusion of future costs, it is important to note that it is becoming increasingly possible to accurately estimate unrelated medical costs in life-years gained. We therefore conclude that the inclusion of unrelated medical costs should become the new standard. http://repub.eur.nl/res/pub/35777/ 2007-07-01T00:00:00Z Introduction: Several studies have estimated health effects resulting from tobacco tax increases. However, studies on the cost effectiveness of tobacco taxes are scarce. The aim of this study was to estimate the cost effectiveness of tobacco tax increases from a health care perspective, explicitly considering medical costs in life years gained. Methods: The effects of a tax increase were translated into effects on smoking quit rates. A dynamic population model then projected incidence, prevalence and health care costs of the major chronic diseases conditional on smoking status over time. Comparing to a current practice scenario, the differences in healthcare costs, tax revenues, life years and QALYs from a tobacco tax increase resulting in a price increase of 10% increase were estimated. Results: Including effects on health care costs in life years gained, the tax increase costs about €2500 per QALY gained. Only 3% of additional tax revenues are enough to compensate additional health care costs in life years gained. Conclusions: Even if the health care costs in life years gained are taken into account and even if additional tax revenues do not flow to the health care sector a tax increase is a cost-effective intervention to increase public health from a health care perspective. http://repub.eur.nl/res/pub/36677/ 2007-04-01T00:00:00Z An important subject of debate in cost-utility analysis of health care programmes is whether to include costs of unrelated medical care in life years gained. The inclusion of such costs is likely to be of consequence in the case of primary prevention. This paper presents different strategies regarding the inclusion not only of the costs, but also of the health effects of unrelated medical care in economic evaluations. Four different cost-utility ratios are presented and related to the criterion of internal consistency. In addition, the possibility to relate the ratios to a well-posed decision problem is analysed. An example computes the different ratios for smoking cessation interventions in different age groups. Including health care costs of unrelated medical care in life years gained increases cost utility ratios, but excluding unrelated medical costs favours smoking cessation interventions targeted at older smokers over those at younger smokers. We conclude that for primary prevention only a cost utility ratio that includes both the costs and effects of unrelated medical care meets the criterion of internal consistency and is related to a meaningful decision problem. Therefore, this type of cost-utility ratio should be preferred even if the data requirements may be substantial. Copyright http://repub.eur.nl/res/pub/36736/ 2007-04-01T00:00:00Z