Basis of assessment
Evidence-based medicine
If the G-BA investigates the diagnostic or therapeutic benefit, medical necessity, and cost-effectiveness of a medical service, or sets standards that must be met in providing care, it must always take the current status of medical knowledge into account. The internationally recognized criteria and standards for evidence-based medicine are definitive for the G-BA.
Evidence-based medicine means basing decisions concerning the expected benefit of a medical method on the body of current scientific knowledge. To achieve that, scientific studies on the relevant topic are systematically searched, and their results evaluated with respect to plausibility and applicability to the current issue.
This procedure allows the experience of a very large number of people with a medical method, as recorded in the studies, to be considered systematically for decision-making. Thus results in evidence-based medicine differ in their quality and validity from personal experiences of individual patients or experts.
The results of scientific studies are taken as evidence for or against the benefit of a medical method. But study results can be flawed. For that reason, an evidence-based approach includes an evaluation of the quality of the evidence of a study based on its design and implementation according to specified rules. The higher the quality of the evidence is found to be, the greater the certainty that the study results reflect the benefit of the medical method in question.
The methods of evidence-based medicine were originally developed for the care of individual patients. In evidence-based healthcare, the same methods of systematic research and evaluation of scientific literature are applied to the provision of medical care for defined population groups.
The standardization of an evidence-based evaluation procedure ensures objectivity, transparency and verifiability in determining the current standard of care. The steps in the procedure are as follows:
- Information extraction: description of the methods and results of the study or information synthesis researched
- Allocation of the studies researched to the levels of evidence according to procedural guidelines
- Methodological assessment of implementation quality and transferability to real-life healthcare
- Synthesis (overview) and final evaluation of all documents considered
Evidence-based selection and evaluation of scientific literature
The evidence-based selection and evaluation of scientific literature is the foundation for decisions on the inclusion or exclusion of medical methods in the SHI schedule of benefits. It ensures that the procedure is transparent and legally sound.
The selection is based on the specific questions of which population group should be treated with which medical method, and what parameters can be used to measure the success of this treatment. The patient-relevant outcomes of a medical method are compiled, and both positive and negative results are analyzed and assessed. Relevant studies are selected using a standardized procedure for searching literature and selecting relevant passages.
The initial step in answering the specific question is a systematic keyword search in professional databases for citations on the topic. Relevant passages are then filtered from the aggregate list in several steps.
Once the raw list has been compiled, an initial screening eliminates irrelevant studies by using previously defined filtering criteria. The literature in the resulting basic list is then procured as full text. This includes the literature submitted in statements before the start of the consultation process. In the second screening, additional restrictions are applied, such as specifying the study type (for example, only controlled studies), the minimum number of subjects for a valid survey, or the target variables.
At the end of the literature evaluation, update research is conducted if the original literature research took place more than six months before. This ensures that the decision on the therapeutic or diagnostic benefit of the method is based on the most up-to-date scientific knowledge.
The result of this procedure is a list of studies in which the study hypotheses are as close as possible to the original question. This list is the scientific basis for decisions taken by the G-BA.
The summary documentation of the final reports includes a comprehensive, transparent account of the entire search strategy. It is published on the G-BA website along with the announcement of the resolution.