key: cord-0053663-pzzablnj
authors: Sikkens, Jonne J.; Collard, Didier; Peters, Edgar J.G.
title: Comparison of hospital treatment strategy or of actually received treatment with hydroxychloroquine in COVID-19?()
date: 2020-12-09
journal: Int J Infect Dis
DOI: 10.1016/j.ijid.2020.12.007
sha: c611ff90056758eb6547ac324df178158b33dd2e
doc_id: 53663
cord_uid: pzzablnj

nan

To the editor,

We read with great interest the publication by Lammers et al., in which they report on the effects of hydroxychloroquine & chloroquine on on-ward mortality and IC admission in hospitalized COVID-19 patients.(1) We commend the authors for their valuable addition to the existing literature on this much discussed subject. It is a thoroughly analysed retrospective cohort study with great attention for detail. The authors chose a setup to minimise bias by indication. However, the study's methodology as described in the article triggers a question with implications for its interpretation.

At several points in the article the authors give the impression that their study design entailed comparing hospital treatment strategies (i.e., comparing hospitals routinely treating their patients with chloroquine with hospitals routinely treating with hydroxychloroquine and with hospitals using neither drug) as opposed to the more commonly used approach of comparing groups of patients that were all actually treated that way. This method approaches the intention-to-treat strategy used in randomized-controlled trials.(2,3) The following sentences in the abstract seem to suggest that the authors compare hospital strategies: "Hospitals were given the opportunity to decide independently on the use of three different COVID-19 treatment strategies: HCQ or CQ, or no treatment. We compared the outcome among these groups." 

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

None.

No conflict of interest to declare. 

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