Longitudinal changes in inflammatory biomarkers among patients with COVID-19: A nationwide study in Iceland

Thora Oskarsdottir, Martin Ingi Sigurðsson, Runólfur Pálsson, E. Eythorsson*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Objectives: All SARS-CoV-2-positive persons in Iceland were prospectively monitored and those who required outpatient evaluation or were admitted to hospital underwent protocolized evaluation that included a standardized panel of biomarkers. The aim was to describe longitudinal changes in inflammatory biomarkers throughout the infection period of patients with COVID-19 requiring different levels of care. Design: Registry-based study. Setting: Nationwide study in Iceland. Patients: All individuals who tested positive for SARS-CoV-2 by real-time polymerase chain reaction (RT-PCR) from February 28 to December 31, 2020 in Iceland and had undergone blood tests between 5 days before and 21 days following onset of symptoms. Measurements and Main Results: Data were collected from the electronic medical record system of Landspitali–The National University Hospital of Iceland. Data analyses were descriptive and the evolution of biomarkers was visualized using locally weighted scatterplot smoothing curves stratified by the worst clinical outcome experienced by the patient: outpatient evaluation only, hospitalization, and either intensive care unit (ICU) admission or death. Of 571 included patients, 310 (54.3%) only required outpatient evaluation or treatment, 202 (35.4%) were hospitalized, and 59 (10.3%) were either admitted to the ICU or died. An early and persistent separation of the mean lymphocyte count and plasma C-reactive protein (CRP) and ferritin levels was observed between the three outcome groups, which occurred prior to hospitalization for those who later were admitted to ICU or died. Lower lymphocyte count, and higher CRP and ferritin levels correlated with worse clinical outcomes. Patients who were either admitted to the ICU or died had sustained higher white blood cell and neutrophil counts, and elevated plasma levels of procalcitonin and D-dimer compared with the other groups. Conclusions: Lymphocyte count and plasma CRP and ferritin levels might be suitable parameters to assess disease severity early during COVID-19 and may serve as predictors of worse outcome.

Original languageEnglish
Pages (from-to)969-977
Number of pages9
JournalActa Anaesthesiologica Scandinavica
Issue number8
Publication statusPublished - 29 Jul 2022

Bibliographical note

Funding Information:
This study was supported by Landspitali University Hospital Science Fund.

Publisher Copyright:
© 2022 Acta Anaesthesiologica Scandinavica Foundation.

Other keywords

  • ambulatory care
  • COVID-19
  • critical care
  • laboratory markers
  • outcome
  • SARS-CoV-2
  • Humans
  • Biomarkers
  • C-Reactive Protein/analysis
  • Iceland/epidemiology
  • Retrospective Studies
  • Ferritins


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