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Search Results: 1 - 10 of 2173 matches for " Uwe Siebert "
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Using decision-analytic modelling to transfer international evidence from health technology assessment to the context of the German health care system
Siebert, Uwe
GMS Health Technology Assessment , 2005,
Abstract: The objective of this Health Technology Assessment (HTA) methods report was to examine and to assess decision analysis (DA) as a method to transfer and adapt international scientific evidence in HTA to the German health care context. Furthermore, we sought to develop a systematic framework to facilitate the selection, transfer, adaptation, and synthesis of these data in German HTA projects. In this report, we review and summarise the concepts and methods of DA; present potential areas of applications, and provide a basis for the critical assessment of decision-analytic studies. The two main methods of DA, decision trees and Markov models, as well as various approaches to sensitivity analyses are described. Examples of typical situations for the use of DA in scientific evidence transfer are described, and a list of main health care domains and parameters in evidence transfer is presented. Finally, we developed a framework to transfer and apply international evidence to the national health care context. The strengths and limitations of the decision-analytic approach are critically examined. In summary, this HTA report describes different situations, in which decision-analytic models can be useful, and demonstrates the utility of DA in transferring and applying international evidence to the national health care context. We developed a systematic instrument to transfer international evidence to the context of other countries and successfully applied this instrument in two German HTA projects. The use of this instrument is recommended in further HTA projects dealing with the application of international evidence to the German health care context. The use of decision-analytic models to transfer international evidence is endorsed. However, the limitations of DA should be clearly stated discussed transparently in all HTA reports.
Pharmacogenomics Bias - Systematic distortion of study results by genetic heterogeneity
Siebert, Uwe,Sroczynski, Gaby,Zietemann, Vera
GMS Health Technology Assessment , 2008,
Abstract: Background: Decision analyses of drug treatments in chronic diseases require modeling the progression of disease and treatment response beyond the time horizon of clinical or epidemiological studies. In many such models, progression and drug effect have been applied uniformly to all patients; heterogeneity in progression, including pharmacogenomic effects, has been ignored. Objective: We sought to systematically evaluate the existence, direction and relative magnitude of a pharmacogenomics bias (PGX-Bias) resulting from failure to adjust for genetic heterogeneity in both treatment response (HT) and heterogeneity in progression of disease (HP) in decision-analytic studies based on clinical study data. Methods: We performed a systematic literature search in electronic databases for studies regarding the effect of genetic heterogeneity on the validity of study results. Included studies have been summarized in evidence tables. In the case of lacking evidence from published studies we sought to perform our own simulation considering both HT and HP. We constructed two simple Markov models with three basic health states (early-stage disease, late-stage disease, dead), one adjusting and the other not adjusting for genetic heterogeneity. Adjustment was done by creating different disease states for presence (G+) and absence (G-) of a dichotomous genetic factor. We compared the life expectancy gains attributable to treatment resulting from both models and defined pharmacogenomics bias as percent deviation of treatment-related life expectancy gains in the unadjusted model from those in the adjusted model. We calculated the bias as a function of underlying model parameters to create generic results. We then applied our model to lipid-lowering therapy with pravastatin in patients with coronary atherosclerosis, incorporating the influence of two TaqIB polymorphism variants (B1 and B2) on progression and drug efficacy as reported in the DNA substudy of the REGRESS trial. Results: We found four studies that systematically evaluated heterogeneity bias. All of them indicated that there is a potential of heterogeneity bias. However, none of these studies explicitly investigated the effect of genetic heterogeneity. Therefore, we performed our own simulation study. Our generic simulation showed that a purely HT-related bias is negative (conservative) and a purely HP-related bias is positive (liberal). For many typical scenarios, the absolute bias is smaller than 10%. In case of joint HP and HT, the overall bias is likely triggered by the HP component and reaches positive val
Economic evaluation of newborn hearing screening: modelling costs and outcomes
Hessel, Franz,Grill, Eva,Schnell-Inderst, Petra,Siebert, Uwe
GMS German Medical Science , 2003,
Abstract: Objectives: The prevalence of newborn hearing disorders is 1-3 per 1,000. Crucial for later outcome are correct diagnosis and effective treatment as soon as possible. With BERA and TEOAE low-risk techniques for early detection are available. Universal screening is recommended but not realised in most European health care systems.Aim of the study was to examine the scientific evidence of newborn hearing screening and a comparison of medical outcome and costs of different programmes, differentiated by type of strategy (risk screening, universal screening, no systematical screening). Methods: In an interdisciplinary health technology assessment project all studies on newborn hearing screening detected in a standardized comprehensive literature search were identified and data on medical outcome, costs, and cost-effectiveness extracted. A Markov model was designed to calculate cost-effectiveness ratios. Results: Economic data were extracted from 20 relevant publications out of 39 publications found. In the model total costs for screening of 100,000 newborns with a time horizon of ten years were calculated: 2.0 Mio.€ for universal screening (U), 1.0 Mio.€ for risk screening (R), and 0.6 Mio.€ for no screening (N). The costs per child detected: 13,395€ (U) respectively 6,715€ (R), and 4,125€ (N). At 6 months of life the following percentages of cases are detected: U 72%, R 43%, N 13%. Conclusions: A remarkable small number of economic publications mainly of low methodological quality was found. In our own model we found reasonable cost-effectiveness ratios also for universal screening. Considering the outcome advantages of higher numbers of detected cases a universal newborn hearing screening is recommended.
Extracorporal hemodialysis with acute or decompensated chronical hepatic failure
Hessel, Franz,Grabein, Kristin,Schnell-Inderst, Petra,Siebert, Uwe
GMS Health Technology Assessment , 2006,
Abstract: Background: Conventional diagnostic procedures and therapy of acute liver failure (ALF) and acute-on-chronic liver failure (ACLF) focus on to identify triggering events of the acute deterioration of the liver function and to avoid them. Further objectives are to prevent the development respectively the progression of secondary organ dysfunctions or organ failure. Most of the times the endocrinological function of the liver can to a wide extent be compensated, but the removal of toxins can only marginally be substituted by conventional conservative therapy. To improve this component of the liver function is the main objective of extracorporal liver support systems. The following principles of liver support systems can be differentiated: Artificial systems, bioartifical systems and extracorporal liver perfusion systems. This HTA report focuses on artificial systems (e.g. BioLogic-DT/-DTPF, MARS, Prometheus), because only these approaches currently are relevant in the German health care system. In 2004 a category "Extracorporal liver assist device" was introduced in the list of "additional payments" in the German DRG-system, which makes reimbursement for hospitals using the technology in inpatient care possible, based on an hospital's individual contract with statutory sickness funds. Objectives: To report the present evidence and future research need on medical efficacy and economic effectiveness of extracorporal liver support devices for treatment of patients with ALF or ACLF based on published literature data. Are artificial liver support systems efficient and effective in the treatment of ALF or ACLF? Methods: An extensive, systematic literature search in medical, economic, and HTA literature data bases was performed. Relevant data were extracted and synthesised. Results: Relevant controlled trials were detected for BioLogic-DT and MARS. No randomised controlled trial on Prometheus was found. None of the included studies on BioLogic-DT showed advantages of the technology compared with standard conventional therapy concerning survival, clinical scores or clinical surrogate parameter like laboratory tests of liver function. Some studies reported complications and side effects of BioLogic-DT. All studies were methodologically insufficient. Concerning the use of MARS overall five studies - three of them randomised - were identified. Two studies reported a significant higher 30d-survival after MARS compared to controls, one study showed a non-significant trend to a better survival probability after one year. The studies showed statistically significant advan
Measurement of fractional flow reserve to guide decisions for percutaneous coronary intervention
Siebert, Uwe,Bornschein, Bernhard,Schnell-Inderst, Petra,Rieber, Johannes
GMS Health Technology Assessment , 2008,
Abstract: Background: Coronary artery disease (CAD) is one of the leading causes of premature death in Germany. Percutaneous coronary interventions (PCI) are frequently performed in patients with angiographically intermediate stenoses. However, the necessity of PCI has not been proven for all patients. Pressure-based fractional flow reserve (FFR) is an invasive test that can be used to assess the functional significance of intermediate coronary stenoses in order to guide decisions on PCI. Objectives: This health technology assessment (HTA) aims to evaluate (1) the diagnostic accuracy, (2) the risk-benefit trade-off and (3) the long-term cost-effectiveness of FFR measurement to guide the decision on PCI in patients with stable angina pectoris and intermediate coronary stenoses. Methods: We performed a literature search in medical and HTA databases. We used the DIMDI instruments (DIMDI = Deutsches Institut für Medizinische Dokumentation und Information/German Institute for Medical Information and Documentation) to assess study quality and to extract and summarize the information in evidence tables. We performed a meta-analysis to calculate the pooled overall estimate for sensitivity and specificity of FFR with 95% confidence intervals (95% CI). Individual studies’ case numbers were used as weights. The influence of single studies and important covariates on the results was tested in sensitivity analyses. We developed the German Coronary Artery Disease Outcome Model (German CADOM), a decision-analytic Markov model, to estimate the long-term effectiveness and cost-effectiveness of FFR measurement in the context of the German healthcare system. Results: Our literature search identified twelve studies relevant to this HTA-report including ten diagnostic accuracy studies of FFR measurement, one randomized clinical trial (RCT) investigating the clinical benefits of this technique as well as one economic evaluation. Pooled estimates for sensitivity and specificity were 81.7% (95% CI: 77.0-85.7%) and 78.7% (95% CI: 74.3-82.7%). Sensitivity analyses indicated robust results. The RCT investigating the efficacy of an FFR-based treatment strategy provided evidence of the advantages of this strategy for patients with respect to freedom from angina and major adverse cardiac events. The published cost-effectiveness study demonstrates that the FFR-based strategy is cost-saving in the US context. Based on our own decision analysis for the German context, the FFR-based strategy improves (quality-adjusted) life-expectancy when compared to universal PCI and is cost-effective in the Ger
Orchiectomy versus medical therapy with LH-RH analogues for the treatment of advanced prostatic carcinoma
Rohde, Volker,Grabein, Kristin,Hessel, Franz,Siebert, Uwe
GMS Health Technology Assessment , 2006,
Abstract: Background: In Germany prostatic cancer is the most frequent cancer in men. The therapy of advanced prostatic cancer has changed significantly from the sub capsulate and / or total orchiectomy to the medical LH-RH analogues therapy during the last ten years, which has considerable effects on results and on costs. Both treatment procedures are based on a slowing down regulation of the growth of the hormone sensitive, neoplastic prostatic cells by the withdrawal of testosterone, which is clinically accompanied by a slowed tumor progression. Objectives: This health technology assessment depicts and evaluates international data of medical effectiveness and efficiency of orchiectomy and medical therapy with LH-RH-analogues in patients with advanced prostate cancer. Methods: A systematic, diversified literature analysis in the common medical, economic and HTA data bases and further media was conducted. Results: Five identified, randomized and controlled studies concerning the application of LH-RH analogues showed the same medical effectiveness of orchiectomy and treatment with LH-RH analogues. Four different studies regarding the quality of life revealed no significant difference between the treatment with LH-RH analogues and the therapy with orchiectomy. Dealing with health economic aspects seven cost-minimizing studies and one cost effectiveness study could be identified. All cost-minimizing studies show methodological restrictions. In general all studies draw the conclusion that the treatment of advanced prostatic cancer with orchiectomy is the most cost effective method, if one assumes a remaining life expectancy of more than one year. Conclusions: According to available studies, there is clear evidence for the equivalent effectiveness of LH-RH analogues and orchiectomy. Until now the studies - due to immense methodological restrictions - could not supply sufficient scientific evidence concerning the aspects of quality of life. In cases of a remaining life expectancy of more than one year, the orchiectomy is the more cost-effective alternative of therapy.
Introduction of organised mammography screening in Tyrol: results following first year of complete rollout
Willi Oberaigner, Martin Daniaux, Sabine Geiger-Gritsch, Rudolf Knapp, Uwe Siebert, Wolfgang Buchberger
BMC Public Health , 2011, DOI: 10.1186/1471-2458-11-673
Abstract: Working from the results of the pilot phase, we extended the organised mammography system to all counties in Tyrol. All women living in Tyrol and covered by compulsory social insurance were invited for a mammography, in the age group 40-59 annually and in the age group 60-69 biennially. Screening mammography was offered mainly by radiologists in private practice, with further assessment performed at hospitals. Using the screening database, all well-established performance indicators were analysed and compared with accepted/desired levels as per the EU guidelines.From June 2008 to May 2009, 120,440 women were invited. Per 1000 mammograms, 14 women were recalled for further assessment, nine underwent biopsy and four cancer cases were detected. Of invasive breast cancer cases, 32.3% and 68.4% were ≤ 10 mm and ≤ 15 mm in size, respectively, and 79.2% were node-negative. The positive predictive value for further assessment and for biopsy was 25.9% and 39.9%, respectively. Estimated two-year participation rate was 57.0%. In total, 14 interval cancer cases were detected during one year of follow-up; this is 18.4% of the background incidence rate.In Tyrol, Austria, an organised mammography screening program was implemented in a smooth transition from an existing spontaneous screening system and was completely rolled out within a short time. The high level of performance already seen in the pilot phase was maintained after rollout, and improvements resulting from the pilot phase were affirmed after one year of complete rollout.Breast cancer is the leading cause of female cancer death in all industrialised countries (and also worldwide), and the breast is also the leading incident cancer site for females [1]. Therefore, screening methods for breast cancer are of greatest public health importance. A recently published Cochrane Review, which assessed the effect of mammography screening for breast cancer on mortality and morbidity concluded that screening is likely to reduce bre
Breast cancer incidence and mortality in Tyrol/Austria after fifteen years of opportunistic mammography screening
Willi Oberaigner, Wolfgang Buchberger, Thomas Frede, Rudolf Knapp, Christian Marth, Uwe Siebert
BMC Public Health , 2010, DOI: 10.1186/1471-2458-10-86
Abstract: To study time trends in breast cancer incidence and mortality, we applied the age-period-cohort model by Poisson regression to the official mortality data covering more than three decades from 1970 to 2006 and to the incidence data ranging from 1988 to 2006. In addition, for incidence data we analysed data on breast cancer staging and compared these with EU guidelines.For the analysis of time trend in breast cancer mortality in age groups 40-79, an age-period-cohort model fits well and shows for years 2002-2006 a statistically significant reduction of 26% (95% CI 13%-36%) in breast cancer mortality as compared to 1992-1996.We see only slight non-significant increases in breast cancer incidence. For the past five years, incidence data show a 10% proportion of in situ cases, and of 50% for cases in stages II+.The opportunistic breast cancer screening programme in Tyrol has only in part exploited the mortality reduction known for organised screening programmes. There seems to be potential for further improvement, and we recommend that an organised screening programme and a detailed screening database be introduced to collect all information needed to analyse the quality indicators suggested by the EU guidelines.Breast cancer (BC) is the leading cause of female cancer death in all industrialised countries (and also worldwide) and the breast is also the leading incident cancer site for females [1]. Therefore, screening methods for BC are of greatest public health importance. Efficiency and efficacy of organised mammography screening programmes have been proven in large randomised trials conducted in Europe and North America. For several years already, organised mammography screening programmes have been recommended in the EU[2]. Austria is one of the European countries where up to 2006 no organised programmes were implemented, but where coverage in spontaneous mammography screening could have been rather high. In a micro-census conducted in Austria in 2006-2007, more tha
HCV-related burden of disease in Europe: a systematic assessment of incidence, prevalence, morbidity, and mortality
Nikolai Mühlberger, Ruth Schwarzer, Beate Lettmeier, Gaby Sroczynski, Stefan Zeuzem, Uwe Siebert
BMC Public Health , 2009, DOI: 10.1186/1471-2458-9-34
Abstract: Literature and international health databases were systematically searched for HCV-specific burden of disease data, including incidence, prevalence, mortality, disability-adjusted life-years (DALYs), and liver transplantation. Data were collected for the WHO European region with emphasis on 22 countries. If HCV-specific data were unavailable, these were calculated via HCV-attributable fractions.HCV-specific burden of disease data for Europe are scarce. Incidence data provided by national surveillance are not fully comparable and need to be standardised. HCV prevalence data are often inconclusive. According to available data, an estimated 7.3–8.8 million people (1.1–1.3%) are infected in our 22 focus countries. HCV-specific mortality, DALY, and transplantation data are unavailable. Estimations via HCV-attributable fractions indicate that HCV caused more than 86000 deaths and 1.2 million DALYs in the WHO European region in 2002. Most of the DALYs (95%) were accumulated by patients in preventable disease stages. About one-quarter of the liver transplants performed in 25 European countries in 2004 were attributable to HCV.Our results indicate that hepatitis C is a major health problem and highlight the importance of timely antiviral treatment. However, data on the burden of disease of hepatitis C in Europe are scarce, outdated or inconclusive, which indicates that hepatitis C is still a neglected disease in many countries. What is needed are public awareness, co-ordinated action plans, and better data. European physicians should be aware that many infections are still undetected, provide timely testing and antiviral treatment, and avoid iatrogenic transmission.Since the discovery of the hepatitis C virus (HCV) in 1989 and its identification as one of the leading causes of chronic liver disease with life-threatening sequelae such as end-stage cirrhosis and liver cancer [1], questions have been raised about the burden of disease caused by the virus.According to the World
Introduction of organised mammography screening in tyrol: results of a one-year pilot phase
Willi Oberaigner, Wolfgang Buchberger, Thomas Frede, Martin Daniaux, Rudolf Knapp, Christian Marth, Uwe Siebert
BMC Public Health , 2011, DOI: 10.1186/1471-2458-11-91
Abstract: In June 2007, the system of opportunistic mammography screening in Tyrol was changed to an organised system by introducing a personal invitation system, a training program, a quality assurance program and by setting up a screening database. All procedures are noted in a written protocol. Most EU recommendations for organised mammography screening were followed, except double reading. All women living in Tyrol and covered by social insurance are now invited for a mammography, in age group 40-59 annually and in age group 60-69 biannually. Screening mammography is offered mainly by radiologists in private practice. We report on the results of the first year of piloting organised mammography screening in two counties in Tyrol.56,432 women were invited. Estimated participation rate was 34.5% at one year of follow-up (and 55.5% at the second year of follow-up); 3.4% of screened women were recalled for further assessment or intermediate screening within six months. Per 1000 mammograms nine biopsies were performed and four breast cancer cases detected (N = 68). Of invasive breast cancer cases 34.4% were ≤ 10 mm in size and 65.6% were node-negative. In total, six interval cancer cases were detected during one year of follow-up; this is 19% of the background incidence rate.In the Tyrolean breast cancer screening program, a smooth transition from a spontaneous to an organised mammography screening system was achieved in a short time and with minimal additional resources. One year after introduction of the screening program, most of the quality indicators recommended by the European guidelines had been reached.However, it will be necessary to introduce double reading, to change the rule for BI-RADS 3, and to concentrate on actions toward improving the participation rate.Breast cancer is the leading cause of female cancer death in all industrialised countries (and also worldwide), and the breast is also the leading incident cancer site for females [1]. Therefore, screening metho
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