Evidence-based Medicine and Clinical Study Designs: Examples of Applications for Allergy Research

Evidence of the effect of clinical interventions in allergology, and in medicine as a whole, can be hierarchically grouped based on the research design producing the evidence. The most weight is given to systematic reviews and meta- analyses, and to randomised controlled trials. These trial designs are superior to non-randomised controlled trials and co- hort studies, which in turn are superior to case-control studies. The least weight is given to case-studies and anecdotal evi- dence. Herein, the principles of evidence-based medicine and clinical study designs are reviewed in the context of exam- ples from the allergology literature.