Evidence map›Paper›PMID 33872186›Full record

Observational studyJournal of medical Internet research2021

Using Unsupervised Machine Learning to Identify Age- and Sex-Independent Severity Subgroups Among Patients with COVID-19: Observational Longitudinal Study.

Julián Benito-León, Mª Dolores Del Castillo, Alberto Estirado, Ritwik Ghosh, Souvik Dubey, J Ignacio Serrano

Open access · goldAbstract readObservational Study
In one paragraph

Observational study in Journal of medical Internet research, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers.

0numbers the graph read from it
0cells of the map it votes in
14citing papers in PubMed
1.3field-weighted citation impact, top 17% 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

14 citing papers in PubMed, 23 citations in OpenAlex.

  1. Review
  2. Article
  3. An Introduction to AI for Clinicians: Tutorial.Interactive journal of medical research · 2026
    Article
  4. Article
  5. Article
  6. Article
  7. Article
  8. Article
  9. Article
  10. Observational
  11. Article
  12. Article
  13. Impact of COVID-19 on a brain damage unit.Diabetes & metabolic syndrome
    Article
  14. 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

6 authors at 5 institutions in 2 countries.

Julián Benito-León *Department of Neurology, University Hospital "12 de Octubre", Madrid, Spain.ORCID 0000-0002-1769-4809
Mª Dolores Del Castillo *Neural and Cognitive Engineering Group, Center for Automation and Robotics, CSIC-UPM, Arganda del Rey, Spain.ORCID 0000-0002-9366-4484
Alberto EstiradoHM Hospitales, Madrid, Spain.ORCID 0000-0003-2163-0485
Ritwik GhoshDepartment of General Medicine, Burdwan Medical College and Hospital, Burdwan, India.ORCID 0000-0002-8192-0807
Souvik DubeyDepartment of Neuromedicine, Bangur Institute of Neurosciences, Kolkata, India.ORCID 0000-0003-1733-3429
J Ignacio Serrano *Neural and Cognitive Engineering Group, Center for Automation and Robotics, CSIC-UPM, Arganda del Rey, Spain.ORCID 0000-0002-9333-1305
Centre for Automation and Robotics · ESBangur Institute of Neurosciences · INBurdwan Medical College & Hospital · INHM Hospitales · ESResearch Institute Hospital 12 de Octubre · ES

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundEarly detection and intervention are the key factors for improving outcomes in patients with COVID-19.

objectiveThe objective of this observational longitudinal study was to identify nonoverlapping severity subgroups (ie, clusters) among patients with COVID-19, based exclusively on clinical data and standard laboratory tests obtained during patient assessment in the emergency department.

methodsWe applied unsupervised machine learning to a data set of 853 patients with COVID-19 from the HM group of hospitals (HM Hospitales) in Madrid, Spain. Age and sex were not considered while building the clusters, as these variables could introduce biases in machine learning algorithms and raise ethical implications or enable discrimination in triage protocols.

resultsFrom 850 clinical and laboratory variables, four tests-the serum levels of aspartate transaminase (AST), lactate dehydrogenase (LDH), C-reactive protein (CRP), and the number of neutrophils-were enough to segregate the entire patient pool into three separate clusters. Further, the percentage of monocytes and lymphocytes and the levels of alanine transaminase (ALT) distinguished cluster 3 patients from the other two clusters. The highest proportion of deceased patients; the highest levels of AST, ALT, LDH, and CRP; the highest number of neutrophils; and the lowest percentages of monocytes and lymphocytes characterized cluster 1. Cluster 2 included a lower proportion of deceased patients and intermediate levels of the previous laboratory tests. The lowest proportion of deceased patients; the lowest levels of AST, ALT, LDH, and CRP; the lowest number of neutrophils; and the highest percentages of monocytes and lymphocytes characterized cluster 3.

conclusionsA few standard laboratory tests, deemed available in all emergency departments, have shown good discriminative power for the characterization of severity subgroups among patients with COVID-19.

Indexed as

Unsupervised Machine LearningAlanine TransaminaseAspartate AminotransferasesCell CountCluster AnalysisCOVID-19C-Reactive ProteinDatasets as TopicEmergency Service, HospitalHumansL-Lactate DehydrogenaseLongitudinal StudiesLymphocytesMonocytesNeutrophilsPrognosisAlanine TransaminaseAspartate AminotransferasesC-Reactive ProteinL-Lactate DehydrogenasecharacterizationCOVID-19data setdetectionemergencyinterventionmachine learningoutcomeseveritysubgrouptesting

Identifiers

PMID33872186
PMCPMC8163491
OpenAlexW3143762511

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.