To the Editor,
We appreciate the comments brought forth by Mungmunpuntipantip et al1 as these will allow us to clarify and shed more light on the finer points of our paper.2 We agree that with retrospective studies controlling for confounding factors can be difficult, and hence, we used propensity score matching to match tocilizumab and non-tocilizumab groups to minimize selection bias. We don’t believe that ferritin levels are an important source of confounding in our paper since both groups were matched for laboratory markers including ferritin levels. Also, usually ferritin levels in metabolic syndrome are much lower than the levels seen in COVID pneumonia. In a 2015 study of 50 subjects with metabolic syndrome, ferritin levels in the range of 187.97 ± 35.95 …
Correspondence: Anup K Singh MD. E-mail: asingh21{at}northwell.edu
