Fallacies in medical practice: Renin-angiotensin-aldosterone system inhibition and COVID-19 as a Paradigm.

In emergency situations, such as during the coronavirus disease 2019 (COVID-19) pandemic, medical community looks for quick answers and guidance. Under these circumstances, experts instead of admitting ignorance, feel obliged to give an answer, often pressurized by political or other authorities, even when such an answer is unavailable. Under these circumstances, publications based on fallacious reasoning are virtually unavoidable. In the present review, we summarize examples underlying fallacious reasoning recommendations regarding treatment with Renin-Angiotensin-Aldosterone inhibitors (RAASi) in the COVID-19 context. Most scientific societies emphasize that RAASi use is safe and that these agents should not be discontinued, based mainly on the results of observational studies (OSs) and occasionally preprints, as relevant randomized controlled trials (RCTs) are currently lacking. However, over the past 4 decades, results from successful RCTs have repeatedly proved that practices based on OSs were wrong. Lack of RCTs results in uncertainty. In this setting, the physician's wisdom and knowledge related to pathophysiologic mechanisms and effect of pharmacologic agents become even more important as they may limit fallacies. Based on these principles, in diseases (e.g., mild, or moderate arterial hypertension, etc.) where equally effective alternative therapies to RAASi are available, these therapies should be applied, whereas in diseases (e.g., heart failure, diabetic kidney disease, etc.), where equally effective alternative therapy compared to RAASi is not available, RAASi should be used. Admittedly this strategy, like all the other recommendations, is not based on solid evidence but is intended to be individualized and follows the Hippocratic "Primum non nocere".