Michał Jakubczyk

Valuation of EQ‐5D Health States in Poland: First TTO‐Based Social Value Set in Central and Eastern Europe

OBJECTIVE Currently, there is no EQ-5D value set for Poland. The primary objective of this study was to elicit EQ-5D Polish values using the time trade-off (TTO) method. METHODS Face-to-face interviews with visitors of inpatients in eight medical centers in Warsaw, Skierniewice, and Puławy were carried out by trained interviewers. Quota sampling was used to achieve a representative sample of the Polish population with regard to age and sex. Modified protocol from the Measurement and Value of Health study was used. Each respondent ranked 10 health states and valued 4 health states using the visual analog scale and 23 using the TTO. Mean and variance stability tests were performed to determine whether using a larger number of health states per respondent would yield credible results. Modeling included random effects and random parameters models. RESULTS Between February and May 2008, 321 interviews were performed. Modeling based on 6777 valuations resulted in an additive model with all coefficients statistically significant, R(2) equal to 0.45, and value -0.523 for the worst possible health state. Means and variance did not differ significantly for states valued in the middle and at the end of the TTO exercise. CONCLUSIONS This is the first EQ-5D value set based on TTO in Central and Eastern Europe so far. Because the values differ considerably from those elicited in Western European countries, its use should be recommended for studies in Poland. Increasing the number of health states that each respondent is asked to value using TTO seems feasible and justifiable.

Coronary Computed Tomographic Prediction Rule for Time-Efficient Guidewire Crossing Through Chronic Total Occlusion : Insights From the CT-RECTOR Multicenter Registry (Computed Tomography Registry of Chronic Total Occlusion Revascularization)

OBJECTIVES This study sought to establish a coronary computed tomography angiography prediction rule for grading chronic total occlusion (CTO) difficulty for percutaneous coronary intervention (PCI). BACKGROUND The uncertainty of procedural outcome remains the strongest barrier to PCI in CTO. METHODS Data from 4 centers involving 240 consecutive CTO lesions with pre-procedural coronary computed tomography angiography were analyzed. Successful guidewire (GW) crossing ≤30 min was set as an endpoint to eliminate operator bias. The CT-RECTOR (Computed Tomography Registry of Chronic Total Occlusion Revascularization) score was developed by assigning 1 point for each independent predictor, and then summing all points accrued. Continuous distribution of scores was used to stratify CTO into 4 difficulty groups: easy (score 0); intermediate (score 1); difficult (score 2); and very difficult (score ≥3). Discriminatory performance was tested by 10-fold cross-validation and compared with the angiographic J-CTO (Multicenter CTO Registry of Japan) score. RESULTS Study endpoint was achieved in 55% of cases. Multivariable analysis yielded multiple occlusions, blunt stump, severe calcification, bending, duration of CTO ≥12 months, and previously failed PCI as independent predictors for GW crossing. The probability of successful GW crossing ≤30 min for each group (from easy to very difficult) was 95%, 88%, 57%, and 22%, respectively. Areas under receiver-operator characteristic curves for the CT-RECTOR and J-CTO scores were 0.83 and 0.71, respectively (p < 0.001). Both the original model fit and 10-fold cross-validation correctly classified 77.3% of lesions. CONCLUSIONS The CT-RECTOR score represents a simple and accurate noninvasive tool for predicting time-efficient GW crossing that may aid in grading CTO difficulty before PCI. (Computed Tomography Angiography Prediction Score for Percutaneous Revascularization for Chronic Total Occlusions [CT-RECTOR]; NCT02022878).

Symmetric versus asymmetric equilibria in symmetric supermodular games

This paper investigates the general properties of symmetric n-player supermodular games with complete-lattice action spaces. In particular, we examine the extent to which all pure strategy Nash equilibria tend to be symmetric for the general case of multi-dimensional strategy spaces. As asymmetric equilibria are possible even for strictly supermodular games, we investigate whether some symmetric equilibrium would always Pareto dominate all asymmetric equilibria. While this need not hold in general, we identify different sufficient conditions, each of which guarantees that such dominance holds: 2-player games with scalar action sets, uni-signed externalities, identical interests, and superjoin payoffs. Various illustrative examples are provided. Finally, some economic applications are discussed.

Coronary Computed Tomographic Angiography for Prediction of Procedural and Intermediate Outcome of Bypass Grafting to Left Anterior Descending Artery Occlusion With Failed Visualization on Conventional Angiography

Conventional coronary angiography (CCA) has considerable limitations regarding visualization of distal vessel segments in chronic total occlusion. We assessed the ability of coronary computed tomographic angiography (CCTA) to predict the success of coronary artery bypass grafting (CABG) to the chronically occluded left anterior descending coronary artery (LAD) incompletely visualized on CCA. Thirty symptomatic patients rejected for CABG on the basis of the CCA findings underwent preoperative CCTA before intended transmyocardial laser revascularization. The LAD was explored operatively in all patients, and CABG to the LAD was attempted if the distal vessel was suitable for anastomosis. The procedural outcome of CABG and the 6-month patency of the left internal mammary artery graft at follow-up CCTA were defined as the primary and secondary end point, respectively. The primary and secondary end points were achieved in 80% and 77% of patients, respectively. We found a significant correlation between the intraoperative and computed tomographic measurement of distal LAD diameter (R = 0.428, p = 0.037). On multivariate analysis, the maximum diameter of the distal LAD by CCTA (odds ratio 8.16, p = 0.043) was the only independent correlate of procedural success of CABG. A cutoff value of 1.5 mm for the mean distal LAD diameter predicted left internal mammary artery graft patency with 100% specificity and 83% sensitivity. Successful CABG resulted in significant improvements in angina class and left ventricular function in LAD segments at 6 months of follow-up. In conclusion, CCTA predicted both the procedural and the intermediate outcome of CABG to chronic LAD occlusion with failed visualization on CCA.

Cost‐effectiveness acceptability curves – caveats quantified

Cost-effectiveness acceptability curves (CEACs) have become widely used in applied health technology assessment and at the same time are criticized as unreliable decision-making tool. In this paper we show how using CEACs differs from maximizing expected net benefit (NB) and when it can lead to inconsistent decisions. In the case of comparing two alternatives we show the limits of the discrepancy between CEAC and expected NB approach and link it with expected value of perfect information. We also show how the shape of CEAC is influenced by the skewness of estimate of expected NB distribution, the correlation between cost and effect estimates and their variance. In the case of more than two options we show when using CEACs can lead to non-transitive choices in pair-wise comparisons and when it lacks independence of irrelevant alternatives property in joint comparisons.

A framework for sensitivity analysis of decision trees

In the paper, we consider sequential decision problems with uncertainty, represented as decision trees. Sensitivity analysis is always a crucial element of decision making and in decision trees it often focuses on probabilities. In the stochastic model considered, the user often has only limited information about the true values of probabilities. We develop a framework for performing sensitivity analysis of optimal strategies accounting for this distributional uncertainty. We design this robust optimization approach in an intuitive and not overly technical way, to make it simple to apply in daily managerial practice. The proposed framework allows for (1) analysis of the stability of the expected-value-maximizing strategy and (2) identification of strategies which are robust with respect to pessimistic/optimistic/mode-favoring perturbations of probabilities. We verify the properties of our approach in two cases: (a) probabilities in a tree are the primitives of the model and can be modified independently; (b) probabilities in a tree reflect some underlying, structural probabilities, and are interrelated. We provide a free software tool implementing the methods described.

Cost-effectiveness versus Cost-Utility Analyses: What Are the Motives Behind Using Each and How Do Their Results Differ?—A Polish Example

OBJECTIVES We aimed to compare the use of cost-effectiveness analysis and cost-utility analysis in health technology assessment in Poland. METHODS We analyzed all the submissions (155) made to the Polish Agency for Health Technology Assessment in the period 2007 to 2011, with 316 intervention-comparator comparisons reporting incremental cost-effectiveness ratios (ICERs) or incremental cost-utility ratios (ICURs). We compared ICERs and ICURs when both were reported (31%), determined factors associated with reporting one or the other, and tested the precision of their assessment. RESULTS In 13% of the cases, ICER and ICUR led to different decisions (were on opposite sides of the willingness-to-pay threshold). Cost-effectiveness analyses were more frequently performed in oncology, offering at the same time more favorable results. It was also more frequent for longer time-horizon models, although then ICER values were on average higher. CONCLUSIONS In Poland, cost-utility analysis is a usual approach of increasing popularity. Interestingly, although assessing ICUR requires additional assumptions, it is estimated more precisely (reported ranges of values in sensitivity analyses are narrower), especially in oncology. ICER and ICUR disagree more often than previously shown in literature. There seem to be no clear signs of biases in submissions (selecting whether to present ICER or ICUR on the basis of their values), but the current study is limited because only the values presented by manufacturers in the submission are available.

What Influences Recommendations Issued by the Agency for Health Technology Assessment in Poland? A Glimpse Into Decision Makers’ Preferences

OBJECTIVE This study aimed to evaluate the factors that are associated with positive (supporting public funding) and negative recommendations of the Agency for Health Technology Assessment in Poland. METHODS Two independent analysts reviewed all the recommendations publicly available online before October 7, 2011. For each recommendation, predefined decision rationales, that is, clinical efficacy, safety, cost-effectiveness, and formal aspects, were sought, either advocating or discouraging the public financing. In the analysis, we used descriptive statistics and a logistic regression model so as to identify the association between predefined criteria and the recommendation being positive. RESULTS We identified 344 recommendations-218 positive (62.8%) and 126 negative (37.2%). Negative recommendations were better justified and also the comments were less ambiguous in accordance with the recommendation (except for clinical efficacy). In general, the specified criteria supported the decision (either positive or negative) in 209 (60.8%), 107 (31.1%), 124 (36.0%), 96 (27.9%), and 61 (17.7%) recommendations, respectively, and ran contrary to the actual decision in the remaining ones. Threshold values for either cost-effectiveness or budget impact distinguishing positive from negative recommendations could not be specified. The following parameters reached statistical significance in logistic regression: clinical efficacy (both explicitly positive and explicitly negative evaluations impacted in opposite directions), lack of impact on hard end points, unfavorable safety profile, cost-effectiveness results, and formal shortcomings (all reduced the probability of a positive recommendation). CONCLUSIONS Decision making of the Agency for Health Technology Assessment in Poland is multicriterial, and its results cannot be easily decomposed into simple associations or easily predicted. Still, efficacy and safety seem to contribute most to final recommendations.

Fuzzy approach to decision analysis with multiple criteria and uncertainty in health technology assessment

Decision making in health technology assessment (HTA) involves multiple criteria (clinical outcomes vs. cost) and risk (criteria measured with estimation error). A survey conducted among Polish HTA experts shows that opinions how to trade off health against money should be treated as fuzzy. We propose an approach that allows to introduce fuzziness into decision making process in HTA. Specifically, in the paper we (i) define a fuzzy preference relation between health technologies using an axiomatic approach; (ii) link it to the fuzzy willingness-to-pay and willingness-to-accept notions and show the survey results in Poland eliciting these; (iii) incorportate uncertainty additionally to fuzziness and define two concepts to support decision making: fuzzy expected net benefit and fuzzy expected acceptability (the counterparts of expected net benefit and cost-effectiveness acceptability curves, CEACs, often used in HTA). Illustrative examples show that our fuzzy approach may remove some problems with other methods (CEACs possibly being non-monotonic) and better illustrate the amount of uncertainty present in the decision problem. Our framework can be used in other multiple criteria decision problems under risk where trade-off coefficients between criteria are subjectively chosen.

Economic resources consumption structure in severe hypoglycemia episodes: a systematic review and meta-analysis

Diabetes mellitus (DM) is associated with severe hypoglycemia events (SHEs) that vary in severity and resource consumption. Here we perform a systematic review in Medline of studies evaluating SHE-related health resource use. Eligible studies investigated patients with DM and included ≥10 SHEs. We also assessed studies identified in another systematic review, and through references from the included studies. We identified 14 relevant studies and used data from 11 (encompassing 6075 patients). Study results were interpreted to fit our definitions, which sometimes required assumptions. SHE type structure was synthesized using Bayesian modeling. Estimating Type 1 & 2 DM separately revealed only small differences; therefore, we used joint results. Of the analyzed SHEs, 9.97% were hospital-treated, 22.3% medical professional-treated, and 67.73% family-treated. These meta-analysis results help in understanding the structure of resource consumption following SHE and can be used in economic studies.