Can a Mendelian Randomization Study Predict the Results of a Clinical Trial? Yes and No
Pages 56-61
Antonio Abbate, Charles A. Dinarello, Mariangela Peruzzi, Sebastiano Sciarretta, Giacomo Frati and Giuseppe Biondi-Zoccai
DOI: http://dx.doi.org/10.6000/1929-6029.2016.05.01.6
Published: 08 January 2016

Abstract: Randomized controlled trials are considered at the top of the evidence hierarchy. However, in several cases randomized trials cannot be conducted or have not yet been completed. In such settings observational studies may provide important inference, yet traditional statistical adjustment methods fall short of controlling for all potential confounders, as unknown confounders cannot be taken care of by even the most sophisticated statistical tools. The mendelian randomization study is a type of research design which simultaneously exploits random transmission of genes and genetic linkage to obtain inferential estimates from the association between specific genetic variants known to modulate given risk factors and the corresponding outcomes of interests. Despite several developments in this field, there remain several areas of further research, and discrepancies between mendelian randomization studies and the corresponding randomized trials have already been recognized. Nonetheless, it is likely that this novel type of study will be used more commonly in the future, and a working knowledge of its pros, cons, and range of validity is crucial for conscientious interpretation and application. We thus aimed to concisely yet poignantly introduce the scholarly reader to this novel type of research design, notwithstanding that complementarity prevails in most cases over overlap between mendelian randomization studies and randomized trials.