Evidence map›Paper›PMID 27586677›Full record

ArticleBMC medical research methodology2016

Multiple time scales in modeling the incidence of infections acquired in intensive care units.

Martin Wolkewitz, Ben S Cooper, Mercedes Palomar-Martinez, Francisco Alvarez-Lerma, Pedro Olaechea-Astigarraga, Adrian G Barnett, Martin Schumacher

Open access · goldAbstract readMulticenter Study
In one paragraph

Article in BMC medical research methodology, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 8 papers.

0numbers the graph read from it
0cells of the map it votes in
8citing papers in PubMed
0.7field-weighted citation impact, top 25% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

8 citing papers in PubMed, 15 citations in OpenAlex.

  1. Article
  2. Article
  3. Article
  4. Smooth Hazards With Multiple Time Scales.Statistics in medicine · 2025
    Article
  5. Article
  6. Article
  7. Exploring the usefulness of Lexis diagrams for quality improvement.BMC medical informatics and decision making · 2020
    Article
  8. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors at 6 institutions in 5 countries.

Martin WolkewitzInstitute for Medical Biometry and Statistics, Faculty of Medicine and Medical Center - University of Freiburg, Freiburg, Germany. wolke@imbi.uni-freiburg.de.
Ben S CooperMahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.
Mercedes Palomar-MartinezHospital Universitari Arnau de Vilanova, Lleida, Universitat Autónoma de Barcelona, Barcelona, Spain.
Francisco Alvarez-LermaService of Intensive Care Medicine, Parc de Salut Mar, Barcelona, Spain.
Pedro Olaechea-AstigarragaService of Intensive Care Medicine, Hospital de Galdakao-Usansolo, Bizkaia, Spain.
Adrian G BarnettInstitute of Health and Biomedical Innovation and School of Public Health and Social Work, Queensland University of Technology, Brisbane QLD, 4059, Australia.
Martin SchumacherInstitute for Medical Biometry and Statistics, Faculty of Medicine and Medical Center - University of Freiburg, Freiburg, Germany.
University of Freiburg · DEHospital de Galdakao · ESMahidol University · THParc de Salut · ESQueensland University of Technology · AUUniversitat Autònoma de Barcelona · ES

Funding

Medical Research Council MR/K006924/1Wellcome Trust 089275/Z/09/Z
6 · The paper itself

Abstract

backgroundWhen patients are admitted to an intensive care unit (ICU) their risk of getting an infection will be highly depend on the length of stay at-risk in the ICU. In addition, risk of infection is likely to vary over calendar time as a result of fluctuations in the prevalence of the pathogen on the ward. Hence risk of infection is expected to depend on two time scales (time in ICU and calendar time) as well as competing events (discharge or death) and their spatial location. The purpose of this paper is to develop and apply appropriate statistical models for the risk of ICU-acquired infection accounting for multiple time scales, competing risks and the spatial clustering of the data.

methodsA multi-center data base from a Spanish surveillance network was used to study the occurrence of an infection due to Methicillin-resistant Staphylococcus aureus (MRSA). The analysis included 84,843 patient admissions between January 2006 and December 2011 from 81 ICUs. Stratified Cox models were used to study multiple time scales while accounting for spatial clustering of the data (patients within ICUs) and for death or discharge as competing events for MRSA infection.

resultsBoth time scales, time in ICU and calendar time, are highly associated with the MRSA hazard rate and cumulative risk. When using only one basic time scale, the interpretation and magnitude of several patient-individual risk factors differed. Risk factors concerning the severity of illness were more pronounced when using only calendar time. These differences disappeared when using both time scales simultaneously.

conclusionsThe time-dependent dynamics of infections is complex and should be studied with models allowing for multiple time scales. For patient individual risk-factors we recommend stratified Cox regression models for competing events with ICU time as the basic time scale and calendar time as a covariate. The inclusion of calendar time and stratification by ICU allow to indirectly account for ICU-level effects such as local outbreaks or prevention interventions.

Indexed as

AlgorithmsCross InfectionHumansIncidenceIntensive Care UnitsLength of StayMethicillin-Resistant Staphylococcus aureusModels, TheoreticalPrevalenceProportional Hazards ModelsRisk AssessmentRisk FactorsSpainStaphylococcal InfectionsTime FactorsCompeting eventsIncidence densityInfectionLeft-truncationReal-time approach

Identifiers

PMID27586677
PMCPMC5009530
OpenAlexW2511299431

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.