Pitfalls when comparing COVID-19-related outcomes across studies-lessons learnt from the ERACODA collaboration

M. Noordzij*, P. Vart, R. Duivenvoorden, C.F.M. Franssen, M.H. Hemmelder, K.J. Jager, L.B. Hilbrands, R.T. Gansevoort

*Corresponding author for this work

Research output: Contribution to journal(Systematic) Review article peer-review

5 Citations (Web of Science)


Reported outcomes, such as incidence rates of mortality and intensive care unit admission, vary widely across epidemiological coronavirus disease 2019 (COVID-19) studies, including in the nephrology field. This variation can in part be explained by differences in patient characteristics, but also methodological aspects must be considered. In this review, we reflect on the methodological factors that contribute to the observed variation in COVID-19-related outcomes and their risk factors that are identified in the various studies. We focus on issues that arose during the design and analysis phase of the European Renal Association COVID-19 Database (ERACODA), and use examples from recently published reports on COVID-19 to illustrate these issues.
Original languageEnglish
Pages (from-to)14-20
Number of pages7
JournalClinical Kidney Journal
Publication statusPublished - 1 Mar 2021


  • COVID-19
  • epidemiology
  • kidney failure
  • mortality
  • outcomes
  • statistics

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