Forschende Komplementärmedizin und klassische Naturheilkunde = Research in complementary and natural classical medicine
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Forsch Komplementarmed Klass Naturheilkd · Aug 2004
Randomized Controlled Trial Multicenter Study Clinical TrialRetrolective, comparative, epidemiological cohort study with parallel groups design for evaluation of efficacy and safety of drugs with "well-established use".
The randomized controlled clinical trial (RCT) is accepted as the "golden standard" for the evaluation of efficacy and safety of new drugs. In contrast, to demonstrate efficacy and safety of drugs with "well-established use" that have been on the European Community market for long time, observational comparative epidemiological studies can be used according to the European drug regulation directive. However, because comparative epidemiological cohort studies can share some risk of bias with other nonrandomized observational study designs, there is a need for an approach that could effectively reduce the bias risk in this type of studies. ⋯ Complementary therapy of patients with primary, non-metastatic breast carcinoma with the mistletoe extract Iscador was safe and in comparison to the control group within the same study cohort showed considerably fewer ADRs attributed to concurrent conventional therapy, reduced disease symptoms, and suggested a significant improvement of survival. Despite some methodical limitations that require careful study planning and conduction as well as critical interpretation, the applied study design seems suitable to evaluate the efficacy and safety of drugs with "well-established use", particularly in oncology.
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Forsch Komplementarmed Klass Naturheilkd · Aug 2004
A framework for classifying study designs to evaluate health care interventions.
Researchers who are trained in epidemiology recognise and use the standard range of designs, i. e. retrospective and prospective cohort studies and case control studies, for studying aetiological questions. The application of study designs to health care interventions is more complex. Researchers may modify familiar designs, in response to specific problems posed by the interventions being evaluated, and an unambiguous nomenclature has not been established. ⋯ Evidence of associations between features of study designs, specific biases and their consistent influence on effect estimates is lacking. A framework for classifying study design will be proposed, based on key features of study designs, i. e. what researchers actually did. This framework may (a) help to reduce the ambiguity about study design labels, and uncertainty about how a study was actually carried out, and (b) help methodological researchers to gather evidence about associations between different study design features and susceptibility to bias.