Portfolio Theory and Cost-Effectiveness Analysis: A Further Discussion

AbstractObjectivesPortfolio theory has been suggested as a means to improve the risk–return characteristics of investments in health-care programs through diversification when costs and effects are uncertain. This approach is based on the assumption that the investment proportions are not subject to uncertainty and that the budget can be invested in toto in health-care programs.MethodsIn the present paper we develop an algorithm that accounts for the fact that investment proportions in health-care programs may be uncertain (due to the uncertainty associated with costs) and limited (due to the size of the programs). The initial budget allocation across programs may therefore be revised at the end of the investment period to cover the extra costs of some programs with the leftover budget of other programs in the portfolio.ResultsOnce the total budget is equivalent to or exceeds the expected costs of the programs in the portfolio, the initial budget allocation policy does not impact the risk–return characteristics of the combined portfolio, i.e., there is no benefit from diversification anymore.ConclusionThe applicability of portfolio methods to improve the risk–return characteristics of investments in health care is limited to situations where the available budget is much smaller than the expected costs of the programs to be funded

Kosten en effecten van esomeprazol in de behandeling van reflux ziekte

Doel. Het bepalen van de kosten-effectiviteit van esomeprazol (Nexium(r)) ten opzichte van alle andere in Nederland geregistreerde protonpomp remmers in de behandeling van reflux ziekte. Voor de effectiviteit vormt het hebben van voldoende controle over de symptomen het uitgangspunt. Perspectief. De studie is uitgevoerd zowel vanuit het perspectief van de verzekeraars als vanuit het maatschappelijk perspectief. Methoden. Gegevens met betrekking tot effectiviteit zijn afgeleid uit een systematische analyse van de literatuur. Gegevens omtrent zorgconsumptie zijn afkomstig uit interviews met huisartsen en gastro-enterologen. Een model is ontwikkeld, dat de gegevens over effectiviteit en kosten van behandeling bijeen brengt. De structuur van het model is vervolgens bediscussieerd met een panel van deskundigen. Tenslotte zijn de berekeningen uitgevoerd met het aangepaste model. Resultaten. Behandeling met esomeprazol 40 mg is dominant ten opzichte van de andere protonpomp remmers: 96,4% van de patiënten heeft na 8 weken voldoende controle over de klachten, tegen totale kosten van EUR 89 (maatschappelijk;m) / EUR 83 (verzekeraar;v). Na esomeprazol 40 mg is omeprazol 40 mg het meest effectief (95,2%), gevolgd door esomeprazol 20 mg (94%)

Mix and match. A simulation study on the impact of mixed-Treatment comparison methods on health-economic outcomes

Background Decision-Analytic cost-effectiveness (CE) models combine many parameters, often obtained after meta-Analysis. Aim We compared different methods of mixed-Treatment comparison (MTC) to combine transition and event probabilities derived from several trials, especially with respect to health-economic (HE) outcomes like (quality adjusted) life years and costs. Methods Trials were drawn from a simulated reference population, comparing two of four fictitious interventions. The goal was to estimate the CE between two of these. The amount of heterogeneity between trials was varied in scenarios. Parameter estimates were combined using direct comparison, MTC methods proposed by Song and Puhan, and Bayesian generalized linear fixed effects (GLMFE) and random effects models (GLMRE). Parameters were entered into a Markov model. Parameters and HE outcomes were compare

Association between lung function and exacerbation frequency in patients with COPD

To quantify the relationship between severity of chronic obstructive pulmonary disease (COPD) as expressed by Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage and the annual exacerbation frequency in patients with COPD. We performed a systematic literature review to identify randomized controlled trials and cohort studies reporting the exacerbation frequency in COPD patients receiving usual care or placebo. Annual frequencies were determined for total exacerbations defined by an increased use of health care (event-based), total exacerbations defined by an increase of symptoms, and severe exacerbations defined by a hospitalization. The association between the mean forced expiratory volume in one second (FEV(1))% predicted of study populations and the exacerbation frequencies was estimated using weighted log linear regression with random effects. The regression equations were applied to the mean FEV(1)% predicted for each GOLD stage to estimate the frequency per stage. Thirty-seven relevant studies were found, with 43 reports of total exacerbation frequency (event-based, n = 19; symptom-based, n = 24) and 14 reports of frequency of severe exacerbations. Annual event-based exacerbation frequencies per GOLD stage were estimated at 0.82 (95% confidence interval 0.46-1.49) for mild, 1.17 (0.93-1.50) for moderate, 1.61 (1.51-1.74) for severe, and 2.10 (1.51-2.94) for very severe COPD. Annual symptom-based frequencies were 1.15 (95% confidence interval 0.67-2.07), 1.44 (1.14-1.87), 1.76 (1.70-1.88), and 2.09 (1.57-2.82), respectively. For severe exacerbations, annual frequencies were 0.11 (95% confidence interval 0.02-0.56), 0.16 (0.07-0.33), 0.22 (0.20-0.23), and 0.28 (0.14-0.63), respectively. Study duration or type of study (cohort versus trial) did not significantly affect the outcomes. This study provides an estimate of the exacerbation frequency per GOLD stage, which can be used for health economic and modeling purposes

TECH-VER: A Verification Checklist to Reduce Errors in Models and Improve Their Credibility

Background In health economic literature, checklists or best practice recommendations on model validation/credibility always declare verifcation of the programmed model as a fundamental step, such as ‘is the model implemented correctly and does the implementation accurately represent the conceptual model?’ However, to date, little operational guidance for the model verifcation process has been given. In this study, we aimed to create an operational checklist for model users or reviewers to verify the technical implementation of health economic decision analytical models and document their verifcation eforts. Methods Literature on model validation, verifcation, programming errors and credibility was reviewed systematically from scientifc databases. An initial beta version of the checklist was developed based on the checklists/tests identifed from the literature and from authors’ previous modeling/appraisa

The ``Outside-In'' Outburst of HT Cassiopeiae

We present results from photometric observations of the dwarf nova system HT Cas during the eruption of November 1995. The data include the first two--colour observations of an eclipse on the rise to outburst. They show that during the rise to outburst the disc deviates significantly from steady state models, but the inclusion of an inner-disc truncation radius of about 4 $R_{wd}$ and a ``flared'' disc of semi-opening angle of $10^{\circ}$ produces acceptable fits. The disc is found to have expanded at the start of the outburst to about $0.41R_{L1}$, as compared to quiescent measurements. The accretion disc then gradually decreases in radius reaching $<0.32R_{L1}$ during the last stages of the eruption. Quiescent eclipses were also observed prior to and after the eruption and a revised ephemeris is calculated.Comment: 9 pages, 11 figures, to appear in MNRA