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HEALTH POLITICAL BACKGROUND: Caries is one of the most prevalent diseases worldwide. For (direct) restaurations of carious lesions, tooth-coloured composite materials are increasingly used. The compulsory health insurance pays for composite fillings in front teeth; in posterior teeth, patients have to bear the extra cost. SCIENTIFIC BACKGROUND: Amalgam is an alloy of mercury and other metals and has been used in dentistry for more than one hundred and fifty years. Composites consist of a resin matrix and chemically bonded fillers. They have been used for about fifty years in front teeth. Amalgam has a long longevity; the further development of composites has also shown improvements regarding their longevity. RESEARCH QUESTIONS: This HTA-report aims to evaluate the longevity (failure rate, median survival time (MST), median age) of direct amalgam fillings in comparison to direct composite fillings in permanent teeth from a medical and economical perspective and discusses the ethical, legal and social aspects of using these filling materials. METHODS: The systematic literature search yielded a total of 1,149 abstracts. After a two-step selection process based on defined criteria 25 publications remained to be assessed. RESULTS: The medical studies report a longer longevity for amalgam fillings than for composite fillings. However, the results of these studies show a large heterogeneity. No publication on the costs or the cost-effectiveness of amalgam and composite fillings exists for Germany. The economic analyses (NL, SWE, GB) report higher costs for composite fillings when longevity is assumed equal (for an observation period of five years) or longer for amalgam compared to composite fillings. These higher costs are due to the higher complexity of placing composite fillings. DISCUSSION: Due to different study designs and insufficient documentation of study details, a comparison of different studies on longevity of direct amalgam and composite fillings in posterior teeth is difficult. Apart from the difficulties in conducting a randomized, controlled long-term study comparing the longevity of direct fillings, the fact that composites and adhesives used in a study have often already been replaced by the next generation of the product at the time of study publication presents an additional problem. Not only the filling material, but also patient parameters and local, intraoral factors (e. g. localisation of the filling) as well as the treating dentist have an impact on the longevity of dental fillings. In evaluating economic studies, one has to refer to the heterogeneity of data on longevity in the medical evaluation. The only effect parameter used in the studies is longevity, other aspects (e. g. long-term functionality) are only referred to in discussions. Extensive counselling of patients regarding the selection of the appropriate filling material is important. CONCLUSIONS: Amalgam fillings show a longer longevity than composite fillings. Two out of six systematic reviews conclude that the expected survival time of composite fillings can be comparable to amalgam fillings. However, these conclusions are based on the results of short-term studies which usually overestimate the longevity of filling materials. From an economic standpoint, amalgam is the more economic filling material compared to direct composite fillings in posterior teeth when considering longevity as the only result parameter. Other aspects than longevity need to be considered in individually choosing the appropriate dental filling material. For future studies aiming to compare the longevity of amalgam and composite fillings, a sufficient sample size and study period, preferably in the setting of a private dental practice, should be aimed for. An evaluation of the cost-effectiveness of amalgam and composite fillings should take the functionality of teeth over a longer time period into account, as well as patients' preferences. The rapid development of composite materials and adhesives make short term revisions of these conclusions necessary.
RESUMO
HEALTH POLITICAL BACKGROUND: About 950,000 people are affected by glaucoma in Germany, about 50% of which are undiagnosed. The German Ophthalmological Society and the German Association of Ophthalmologists recommend a screening for glaucoma according to their guidelines. The Federal Joint Committee disapproved a glaucoma-screening program on expense of the compulsory health insurance in 2004. SCIENTIFIC BACKGROUND: Primary open angle glaucoma is diagnosed by evaluation of the optic disc, the retinal fibre layer and the visual field. The main examinations are ophthalmoscopy, scanning laser polarimetry, confocal scanning laser ophthalmoscopy, retinal thickness analysis and optical coherence tomography. Scotomas are diagnosed by perimetry (standard automated perimetry, short wavelength automated perimetry and frequency doubling perimetry). The intraocular pressure is the most important treatable risk factor and is measured by (contact or non-contact) tonometry. RESEARCH QUESTIONS: The aim of this HTA-report is to investigate the diagnostic validity and cost effectiveness of diagnostic techniques or combinations of these methods with respect to the use in a screening setting in Germany. METHODS: A systematic literature research was performed in 35 international databases and yielded 2602 articles. Overall 57 publications were included for assessment, according to predefined selection criteria. RESULTS: The 55 medical articles deal mainly with frequency doubling perimetry, confocal scanning laser ophthalmoscopy and scanning laser polarimetry. Few articles cover short wavelength automated perimetry, tonometry and ophalmocopic evaluations by ophthalmologists. The quality of the papers is generally low, as far as the evidence in respect of screening is concerned. No single method exists with both, high sensitivity and high specificity for screening purpose. Data are also not sufficient to recommend combinations of methods. Only two economic models on cost-effectivenes of screening investigations could be identified. No economic evaluations of the most recent methods can be found in the published literature. A British cost-effectiveness analysis calculates cost per true positives and favours a combination of ophthalmoscopy, tonometry and perimetry either for people at high risk for glaucoma or for the total population as an initial examination. A Canadian HTA-report models the cost per year of blindness avoided. The report concludes that because of a high degree of uncertainty with respect to the benefits and the high costs involved, the setting-up of a glaucoma-screening program cannot be supported. DISCUSSION: The literature shows that combinations of methods have to be used for screening of glaucoma in order to get reasonable values of sensitivity and specificity. Presently no combination of methods and no algorithm can be presented for glaucoma screening with sufficient evidence. Also no conclusions about cost-effectiveness for Germany can be made based on the available literature. CONCLUSIONS: In order to find the optimal combination of methods for glaucoma-screening, population-based studies have to be performed. Therefore also no final conclusions can be drawn with respect to cost-effectiveness of glaucoma-screening methods. The economic evaluation of a clinical effective screening-method should consider the effects of blindness avoided, as well as effects on the prevention of visual impairment.
RESUMO
BACKGROUND: In 2003 nearly 20% of deaths in Germany were caused by coronary heart disease (CHD). Risk models are used to estimate the ten-year-risk of a coronary event. Coronary calcification may be seen as an additional risk factor. The amount of calcium is correlated with atherosclerotic lesions, but there is no direct correlation with the probability of a plaque rupture. Coronary calcification may be measured either by electron beam computed tomography (EBCT) or multi-detector computed tomography (MDCT). OBJECTIVES: The aim of this HTA report is to investigate the diagnostic validity and cost effectiveness of computed tomography techniques in measuring coronary calcification of asymptomatic risk patients. Ethical aspects are discussed. METHODS: A systematic literature research was performed in 35 international databases which yielded 1080 articles. Overall 43 publications were included for assessment, according to predefined selection criteria. RESULTS: Measuring coronary calcification offers additional information compared with traditional risk factors. Yet at present it cannot be said - according to published literature - which population groups gain most. For determining adequate calcium score thresholds standardisation for age and sex is important. When comparing the reference standard EBCT with MDCT results are inconsistent and depend on the calcium-score value as well as on the scoring method. EBCT as a triage instrument in diagnosing CHD appears to be cost-effective. Yet it is rather not cost-effective as a refinement tool for risk stratification. DISCUSSION: Most of the literature was published in the United States and discusses the use of EBCT as well as (traditional) risk stratification by the Framingham Score. Regarding coronary calcification measured by MDCT (which is more widespread in Germany than EBCT) and a risk model applicable for European populations clear recommendations based on published literature cannot be made at present. CONCLUSION: In conclusion measuring coronary calcification is a promising tool for improving risk stratification with established risk models. Nevertheless many questions remain concerning the targeted use in medical practice, particularly regarding European populations. Therefore also no final conclusions can be drawn with respect to cost-effectiveness. The evaluation of diagnostic procedures measuring other parameters than coronary calcium with regard to CHD risk stratification, compared to EBCT or MDCT, is not part of this report.
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BACKGROUND: The European Agency for the Evaluation of Medicinal Products (EMEA) granted market authorisation to the heptavalent pneumococcal vaccine Prevenar (Wyeth) in the year 2001. The indication of Prevenar is the active immunisation of infants and young children under the age of two against invasive disease caused by Streptococcus pneumonia serotypes 4, 6B, 9V, 14, 18C, 19F and 23F. At the time of this study the German vaccination scheme advises the immunisation with Prevenar only for children at high risk. OBJECTIVES: The objective of the study is first to determine the efficacy and effectiveness of the immunisation of all children with the heptavalent conjugated pneumococcal vaccine in Germany and second, whether a general recommendation for vaccination of all children would be cost-effective. METHODS: A systematic literature search was performed in 29 relevant databases for the period of January 1999 to June 2004. Thus 1,884 articles were identified which were then assessed according to predefined selection criteria. RESULTS: There is evidence for the medical effectiveness of Prevenar against invasive pneumococcal disease caused by the covered serotypes from a major double-blinded RCT undertaken in California. The vaccine shows lower values of effectiveness against otitis media and pneumonia. The values for effectiveness of the vaccine in Germany are below the data for California because of the different incidence of Serotypes. The cost-effectiveness rates for an immunisation of all children with Prevenar vary across different countries. One reason - besides different Health Systems - can be seen in the uncertainty about the duration of protection, another in the assumption on regional serotype coverage of the vaccine. From the healthcare payers' perspective a general vaccination of all children in Germany is not cost-effective, from a societal perspective the benefits from vaccination could prevail the cost. The actual price of the vaccine (if financed by the Healthcare Payer, 2004) has dropped and is lower than the assumed price in the German cost-effectiveness study. This fact could raise the cost-effectiveness-ratio of a general immunisation. DISCUSSION: The low evidence of information on the herd immunity effect of pneumococcal immunisation, the occurrence on serotype-replacement phenomenon and the effects on the prevalence of antibiotic-resistant strains shall be considered when deciding whether the pneumococcal vaccination for all infants and young children should be added to the German vaccination scheme. There is also little information on the duration of vaccine effectiveness and regional effectiveness because of different serotype incidence. The economic models thus incorporate some uncertainties. CONCLUSION: At present, relatively few pneumococcal strains in Germany show antibiotic resistance. This situation shall further be observed while improving the data evidence for future decisions (epidemiologic data of incidence of pneumococcal diseases and serotyping of pneumococcal bacteria). From the economic perspective no distinct recommendation to add the conjugated vaccination for all children to the German vaccination scheme can be given. This situation may change if the price for the vaccine further decreases. Furthermore a future cost-effectiveness analysis for Germany should incorporate the effects of the replacement phenomenon, the herd immunisation effects and the effects of the vaccination on the antibiotic-resistant pneumococcal strains.
