Annemieke De Ridder

Healthcare use, social burden and costs of children with and without ADHD in Flanders, Belgium

AbstractBackground: The purpose of this study was to provide quantitative information on the economic, social and emotional burden borne by families of children with attention-deficit hyperactivity disorder (ADHD) and on the public healthcare costs of a child with ADHD in Flanders, Belgium, and to compare costs of ADHD children with those of siblings without the disorder. Methods: A pilot-tested questionnaire was sent to all members of the Flemish ADHD society in February 2003. Parents were asked to record utilisation of healthcare, social care and other non-medical resources for their ADHD child and his/her sibling. In addition, data were collected on ADHD severity (IOWA-Conners Rating Scale) and on the sociodemographic and economic characteristics of the parents. Parents’ out-of-pocket and public annual costs were calculated using tariffs. These costs were corrected for several confounding variables using general linear model (GLM) estimates. Results: ADHD affects school results and parents’ productivity and places a psychological and emotional burden on the family. Childhood ADHD also results in a significantly higher use of healthcare: ADHD children have a significantly higher probability of visiting a general practitioner (60.3% vs 37.4%) and a specialist (50.9% vs 12.9%); they also visit the emergency department significantly more often (26% vs 12.1%), and they are hospitalised significantly more often (14% vs 8.4%). Consequently, Flemish children with ADHD incur significantly higher medical costs than their siblings without the disorder. Even after correction for several covariates, these cost differences are still striking. In fact, compared with their sibling, the annual cost for an ADHD child is more than six times higher for the parent (€588.3 vs €91.5), and public costs are twice as high (€779 vs €371.3) [year of costing 2002]. Conclusions: Childhood ADHD results in significantly higher use of healthcare and adversely affects academic achievements and parents’ productivity.

Cost effectiveness of drug-eluting stents in Belgian practice: healthcare payer perspective.

AbstractBackground: There has been a steep increase in the number of percutaneous coronary intervention procedures performed for coronary heart disease since their introduction about 30 years ago. Recently, the use of drug-eluting stents (DES) compared with the original bare metal stents (BMS) has increased in many countries.Objective: To assess the cost effectiveness of DES versus BMS in a real-world setting from the Belgian healthcare payer perspective.Methods: We developed a decision analysis model to estimate incremental costs (year 2004 or 2007 values [depending on the underlying variable]) and effectiveness. Incremental effectiveness was calculated by combining relative benefits from published meta-analyses with real-world observations from a Belgian registry. Probabilistic modelling and sensitivity analyses were performed. The model had a 1-year time horizon. Sixteen sub groups were created based on the following characteristics: initial stent type, diabetic status, complex lesion and multi-vessel disease. Scenario analyses were performed for the influence on reinterventions and the duration of clopidogrel use. In each analysis, 1000 Monte Carlo simulations were performed.Results: The incremental costs for switching from BMS to DES are substantial (approximately €1000), while the benefits, expressed as QALYs, are extremely small (on average <0.001 QALYs gained). This led to very high incremental cost-effectiveness ratios: over €860 000 per QALY gained in all subgroups and scenario analyses.Conclusion: Comparing DES with BMS, no life-years are gained and small quality-of-life improvements are achieved for short periods, resulting in a high likelihood that DES are not cost effective. When there is competition for scarce resources this should be considered when deciding on the reimbursement of this technology.

Comparing the cost effectiveness of risperidone and olanzapine in the treatment of schizophrenia using the net-benefit regression approach.

To estimate the cost effectiveness of olanzapine and risperidone for the treatment of schizophrenia in Belgium. Data were retrieved from a prospective, observational, non-randomized, follow-up survey. Clinical investigators assigned 265 patients with schizophrenia to either olanzapine (n = 136) or risperidone (n = 129). Patients were followed up for 2 years. Total healthcare costs were determined from the public payer perspective and calculated by multiplying resource use with official tariffs; effectiveness of the drugs was measured with the EQ-5D. This study uses a net-benefit regression approach to accommodate for baseline differences between treatment groups and uncertainty. Total 2-year costs were very similar for patients receiving risperidone and olanzapine (euro20 915.33 and euro20 569.69, respectively; p = 0.925) [year 2002 values]. The health condition of the patients receiving risperidone was better than that of patients receiving olanzapine but not significantly so (1.46 and 1.41, respectively; p = 0.191). Simple ordinary least squares (OLS) regressions indicated that, for lambda = euro40 000, we could not reject the null hypothesis that the drugs provide similar net monetary benefits to the patient (risperidone vs olanzapine euro2046.95; p = 0.656). When we controlled for several patient characteristics, risperidone moved further away from olanzapine but the difference did not reach statistical significance (risperidone vs olanzapine euro3198.07; p = 0.595). Numerous sensitivity analyses confirmed the robustness of the results. Results of this study suggest that it is important to control for baseline patient characteristics when performing a cost-effectiveness analysis. No significant difference in net monetary benefit was found between risperidone and olanzapine.AbstractObjective: To estimate the cost effectiveness of olanzapine and risperidone for the treatment of schizophrenia in Belgium. Methods: Data were retrieved from a prospective, observational, nonrandomized, follow-up survey. Clinical investigators assigned 265 patients with schizophrenia to either olanzapine (n = 136) or risperidone (n = 129). Patients were followed up for 2 years. Total healthcare costs were determined from the public payer perspective and calculated by multiplying resource use with official tariffs; effectiveness of the drugs was measured with the EQ-5D. This study uses a net-benefit regression approach to accommodate for baseline differences between treatment groups and uncertainty. Results: Total 2-year costs were very similar for patients receiving risperidone and olanzapine (€20 915.33 and €20 569.69, respectively; p = 0.925) [year 2002 values]. The health condition of the patients receiving risperidone was better than that of patients receiving olanzapine but not significantly so (1.46 and 1.41, respectively; p = 0.191). Simple ordinary least squares (OLS) regressions indicated that, for λ = €40 000, we could not reject the null hypothesis that the drugs provide similar net monetary benefits to the patient (risperidone vs olanzapine €2046.95; p = 0.656).When we controlled for several patient characteristics, risperidone moved further away from olanzapine but the difference did not reach statistical significance (risperidone vs olanzapine €3198.07; p = 0.595). Numerous sensitivity analyses confirmed the robustness of the results. Conclusion: Results of this study suggest that it is important to control for baseline patient characteristics when performing a cost-effectiveness analysis. No significant difference in net monetary benefit was found between risperidone and olanzapine.

Can we account for selection bias? A comparison between bare metal and drug-eluting stents.

OBJECTIVE In this article we investigate the possibility to account for selection bias in observational data by using econometric techniques. METHODS One-year costs of 15,237 patients who received a drug-eluting stent (DES) or a bare metal stent (BMS) in Belgium in 2004 were compared. The treatment choice between DES and BMS could be influenced by patient characteristics; therefore, cost estimates could be biased by overt and/or hidden selection bias. Overt bias was addressed by regression adjustment and propensity score matching. Hidden selection bias was dealt with by using an instrumental variable (IV) approach. RESULTS Due to the higher purchase price DES patients incur higher (unadjusted) costs in the short-term; these costs are, however, compensated in the long-term due to less in-stent restenosis and hospitalizations. Analyses indicated that, for the diabetic population, the null hypothesis of similar average 1-year costs of patients receiving a BMS or DES cannot be rejected. For the non-diabetic patients a significant cost difference between BMS and DES patients was found. It cannot be ruled out that the treatment-effect model does not correct for all observable or unobservable characteristics and that the estimated treatment effect is biased, possibly due to weak instruments. CONCLUSION It is interesting and necessary to explore the use of econometric tools in cost and cost effectiveness analysis to investigate the effect of a technology in everyday practice and to take into account patient and disease characteristics and uncertainty. Further research is however necessary to investigate how we can fully correct for selection bias when using observational data.

The impact of assessment tasks on subsequent examination performance

In this article, the impact of assessment tasks on examination result (measured by examination grades) is investigated. Although many describe the advantages of electronic assessment tasks, few stu...In this article, the impact of assessment tasks on examination result (measured by examination grades) is investigated. Although many describe the advantages of electronic assessment tasks, few studies have been undertaken which compare a traditional approach using a classical examination with a new approach using assessment tasks. The main hypothesis of this study is that assessment tasks have a positive impact on results. It should motivate students to avoid procrastination and to adopt a deep learning approach. We test this research hypothesis in a case study with undergraduate students in their second year at university. Study results of students before and after the implementation of the assessment tasks are compared using t-tests. A regression analysis is performed to investigate the impact of the assessment tasks on the examination result. Empirical evidence of whether or not a positive effect of assessment tasks on the examination result is presented. The impact of how assessment tasks affect students with differing levels of performance is provided, and implications for educators is offered.

Economic analysis of the use of drug-eluting stents from the perspective of Belgian health care.

Objective — Recent evidence shows that drug-eluting stent devices (DES) substantially reduce the risk of in-stent restenosis compared with classic bare metal stent devices (BMS). In Belgium, however, the use of BMS is still standard procedure due to the higher prices of the newer DES. Although the use of DES is more expensive in the short term it might be beneficial in the long term due to the avoidance of revascularization costs.The primary objective of this study is to compare the net cost of DES and BMS from the perspective of Belgian health care. Methods and results — Cost differences between DES and BMS are determined by the difference in stent price and the difference in the rate of re-intervention.The cost of revascularization of patients with in-stent restenosis was estimated based on data gathered at the Antwerp University hospital (UZA). Data on effectiveness were obtained from a literature meta-analysis. Because of some important study limitations, a sensitivity analysis was included in this study. In general, the use of DES was cost saving as compared with BMS, with savings amounting to € 165 for Cypher stent devices and € 128 for Taxus stent devices in the base case scenario. For patients with a high risk of restenosis net savings persist in almost all sensitivity analyses. Conclusion — The use of DES in patients with a high in-stent restenosis risk is cost saving. Price evolutions in the stent device market predict that the use of DES, if not yet cost saving, will become cost saving in the near future for all types of patients. Recent evidence, however, casts some doubt on the long-term effectiveness of DES.

Order bias in estimates of willingness to pay for drugs to treat attention-deficit/hyperactivity disorder.

This study investigated the presence of order bias in contingent valuation studies. We compared the willingness to pay (WTP) for an improved drug for attention-deficit/hyperactivity disorder with that for the standard drug and examined whether the order in which the drugs are presented influences the results obtained. A pretested questionnaire was administered to 114 university students. WTP was elicited using the payment card method. A split sample was used to test order bias. The average WTP per month was €57.34 for the standard drug and €81.95 for the new drug. The results show that WTP for a new drug varies according to the order in which the drugs are presented. Respondents stated a higher WTP for the new drug if the standard therapy was presented first. This may be due to order bias, evidence of which has also been found in other studies and which is considered to be a limitation of the method. Finally, the use of marginal WTP is suggested as a solution.This study investigated the presence of order bias in contingent valuation studies. We compared the willingness to pay (WTP) for an improved drug for attention-deficit/hyperactivity disorder with that for the standard drug and examined whether the order in which the drugs are presented influences the results obtained. A pretested questionnaire was administered to 114 university students. WTP was elicited using the payment card method. A split sample was used to test order bias. The average WTP per month was €57.34 for the standard drug and €81.95 for the new drug. The results show that WTP for a new drug varies according to the order in which the drugs are presented. Respondents stated a higher WTP for the new drug if the standard therapy was presented first. This may be due to order bias, evidence of which has also been found in other studies and which is considered to be a limitation of the method. Finally, the use of marginal WTP is suggested as a solution.