key: cord-0759051-wyfay469
authors: Sriwijitalai, Won; Wiwanitkit, Viroj
title: IL-6 serum level and olfactory dysfunction severity in COVID-19: correspondence
date: 2022-03-04
journal: Eur Arch Otorhinolaryngol
DOI: 10.1007/s00405-022-07296-9
sha: 10e1d92b2e065c1480d43eafa82ac961a8a0f742
doc_id: 759051
cord_uid: wyfay469

nan

Dear Editor, we would like to comment on the publication "Correlations between IL-6 serum level and olfactory dysfunction severity in COVID-19 patients: a preliminary study [1] ." Vaira et al. concluded that "In COVID-19 patients, psychophysical olfactory scores did not show significant correlations with the plasma levels of a well-recognized negative prognostic factor such as IL-6. This observation casts some shadows on the positive prognostic value of olfactory dysfunctions. [1] ." We agree that it is interesting to try to find clinical correlation between olfactory symptom and a laboratory parameter for inflammation. Regarding IL-6, it is an inflammatory marker and might be associated with many confounding factors. Nevertheless, an important concern on this report is on the statistical method. In general, a correlation analysis is based on the two continuous parameters, which are derived from measurement. In the present work, IL-6 is a continuous parameter but the psychophysical olfactory scores are derived from a scoring system and is a numerical scale from a basic counting. Therefore, the correlation should not be valid and the derived coefficient parameter cannot be further interpreted. This kind of pitfall is a common statistical error in clinical association study [2] .

Correlations between IL-6 serum level and olfactory dysfunction severity in COVID-19 patients: a preliminary study

Statistics in biomedical laboratory and clinical science: applications, issues and pitfalls