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Biomarkers for length of hospital stay, changes in muscle mass, strength and physical function in older medical patients: protocol for the Copenhagen PROTECT study—a prospective cohort study
  1. Rikke S Kamper1,2,
  2. Martin Schultz3,2,
  3. Sofie K Hansen1,2,
  4. Helle Andersen4,2,
  5. Anette Ekmann1,2,
  6. Hanne Nygaard5,2,
  7. Fredrik Helland6,
  8. Miriam R Wejse6,
  9. Camilla B Rahbek1,
  10. Tim Noerst1,
  11. Eckart Pressel6,
  12. Finn Erland Nielsen5,7,
  13. Charlotte Suetta1,3
  1. 1Geriatric Research Unit, Department of Geriatric and Palliative Medicine, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark
  2. 2CopenAge; Copenhagen Center for Clinical Age Research, University of Copenhagen, Copenhagen, Denmark
  3. 3Geriatric Research Unit, Department of Medicine, Copenhagen University Hospital, Herlev and Gentofte, Herlev, Denmark
  4. 4Department of Occupational and Physiotherapy, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark
  5. 5Department of Emergency Medicine, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark
  6. 6Department of Geriatric and Palliative Medicine, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark
  7. 7Copenhagen Center for Translational Research, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark
  1. Correspondence to Rikke S Kamper; rikke.stefan.kamper.01{at}


Introduction Sarcopenia is generally used to describe the age-related loss of muscle mass and strength believed to play a major role in the pathogenesis of physical frailty and functional impairment that may occur with old age. The knowledge surrounding the prevalence and determinants of sarcopenia in older medical patients is scarce, and it is unknown whether specific biomarkers can predict physical deconditioning during hospitalisation. We hypothesise that a combination of clinical, functional and circulating biomarkers can serve as a risk stratification tool and can (i) identify older acutely ill medical patients at risk of prolonged hospital stays and (ii) predict changes in muscle mass, muscle strength and function during hospitalisation.

Method and analysis The Copenhagen PROTECT study is a prospective cohort study consisting of acutely ill older medical patients admitted to the acute medical ward at Copenhagen University Hospital, Bispebjerg and Frederiksberg, Denmark. Assessments are performed within 24 hours of admission and include blood samples, body composition, muscle strength, physical function and questionnaires. A subgroup of patients transferred to the Geriatric Department are included in a smaller geriatric cohort and have additional assessments at discharge to evaluate the relative change in circulating biomarker concentrations, body composition, muscle strength and physical function during hospitalisation. Enrolment commenced 4 November 2019, and proceeds until August 2021.

Ethics and dissemination The study protocol has been approved by the local ethics committee of Copenhagen and Frederiksberg (H-19039214) and the Danish Data Protection Agency (P-2019-239) and all experimental procedures were performed in accordance with the Declaration of Helsinki. Findings from the project, regardless of the outcome, will be published in relevant peer-reviewed scientific journals in online (

Trial registration number NCT04151108

  • risk management
  • statistics & research methods
  • geriatric medicine

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  • Correction notice This article has been corrected since it first published. The provenance and peer review statement has been included.

  • Contributors RSK, CS, MS and FEN drafted the manuscript. CS, FEN, RSK, MS, AE, HN, HA, MRW and EP designed the study. SKH, HA, HN, AE, FH, MRW, EP, TN and CBR contributed to the discussion, edited and reviewed the manuscript. All authors read and approved the final manuscript.

  • Funding The work is supported by funding from the Novo Nordisk Foundation; grant number NNF18OC0052826.

  • Disclaimer The funders take no part in the design of the study; in the collection, analysis or interpretation of data; in the writing of manuscripts or decisions regarding publication.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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