Response to: 'Correspondence on 'Historically controlled comparison of glucocorticoids with or without tocilizumab versus supportive care only in patients with COVID-19- associated cytokine storm syndrome: results of the CHIC study by Klopfenstein et al

In rheumatology and beyond, clinical trial researchers often interpret observed treatment contrasts (between two trial arms) as if these contrasts are constant across the entire spectrum of disease severity. While understandable, researchers, regulators and society usually aim at finding one effective treatment for the whole disease, a constant effect interpretation is a simplification of the truth. Often, effective treatments have relatively most effect when applied in the sickest. Benefit may be less impressive when applied in those with milder disease: effect modification or (statistical) interaction. Klopfenstein et al touch on this rather ubiquitous but often ignored phenomenon, by demonstrating that the treatment contrast of tocilizumab versus control in trials with patients with COVID-19 is not constant but depends on the trial patients’ baseline severity, here expressed as the risk to die in the control arms of the trials.1 One may speculate why this common principle is so...
Source: Annals of the Rheumatic Diseases - Category: Rheumatology Authors: Tags: ARD, COVID-19 Correspondence response Source Type: research