Evidence map›Paper›PMID 42115988›Full record

Observational studyBMC infectious diseases2026

Follow-up, diagnosis, and outcomes of fever of unknown origin cases in whom no diagnosis was established after initial evaluation: an ID-IRI (Infectious Diseases - International Research Initiative) observational retrospective cohort study.

Umran Elbahr, Hakan Erdem, Amel Letaief, Svjetlana Grgić, Lysien Ivania Zambrano, Wissal Ben Yahia, Bilal Ahmad Rahimi, Magdalena Baymakova, Reham Khedr, Emmanuel Nsutebu and 6 more

Abstract readObservational StudyMulticenter Study
In one paragraph

Observational study in BMC infectious diseases, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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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

0 citing papers in PubMed.

No citing paper in PubMed yet.

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

16 authors.

Umran ElbahrDepartment of Infectious Diseases, Bahrain Oncology Center, King Hamad University Hospital, Muharraq, Bahrain. drumran_08@hotmail.com.
Hakan ErdemDepartment of Infectious Diseases and Clinical Microbiology, Gulhane School of Medicine, Turkish Health Sciences University, Ankara, Turkey.
Amel LetaiefDepartment of Infectious Diseases, Farhat Hached University Hospital, Ibn El Jazzar Medical School, University of Sousse, Sousse, Tunisia.
Svjetlana GrgićDepartment of Infectious Diseases, University Clinical Hospital Mostar, Mostar, Bosnia and Herzegovina.
Lysien Ivania ZambranoDepartment of Morphological Sciences, Faculty of Medical Sciences (FCM), National Autonomous University of Honduras (UNAH), GRINVAR Research Group, Tegucigalpa, Honduras.
Wissal Ben YahiaDepartment of Internal Medicine, Farhat Hached University Hospital, Ibn El Jazzar Medical School, University of Sousse, Sousse, Tunisia.
Bilal Ahmad RahimiDepartment of Infectious Diseases, Kandahar University Medical Faculty, Teaching Hospital, Kandahar, Afghanistan.
Magdalena BaymakovaDepartment of Infectious Diseases, Military Medical Academy, Sofia, Bulgaria.
Reham KhedrDepartment of Pediatric Oncology, National Cancer Institute - Cairo University, Children Cancer Hospital Egypt, Cairo, Egypt.
Emmanuel NsutebuTropical and Infectious Diseases Division, Sheikh Shakhbout Medical City, Abu Dhabi, United Arab Emirates.
Gamze ŞanlıdağDepartment of Infectious Diseases and Clinical Microbiology, Faculty of Medicine, Ege University, Bornova, Izmir, Turkey.
Meliha Meriç KoçDepartment of Infectious Diseases & Clinical Microbiology, School of Medicine, Bezmialem Vakif University, Istanbul, Turkey.
Serkan ÖncüDepartment of Infectious Diseases & Clinical Microbiology, School of Medicine, Adnan Menderes University, Aydin, Turkey.
Kostadin PoposkiFaculty of Medicine, University Clinic for Infectious Diseases and Febrile Conditions, Skopje, Republic of North Macedonia.
Gülden Eser-KarlıdağDepartment of Infectious Diseases and Clinical Microbiology, University of Health Sciences, Elazığ Fethi Sekin City Hospital, Elazığ, Turkey.
Oğuz Reşat SipahiDepartment of Infectious Diseases, Bahrain Oncology Center, King Hamad University Hospital, Muharraq, Bahrain.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

BACKGROUND/

aimIn fever of unknown origin (FUO), despite comprehensive evaluation a substantial proportion of patients may remain without a definitive diagnosis. Herein, we aimed to analyse the disease course, mortality rate, final diagnosis, and the workup performed to reach final diagnosis in fever of unknown origin without final diagnoses (FUOWFD) cases. MATERIALS AND

methodsThe roster of patients with FUOWFD was obtained from a previously published multicenter study. Subsequently, additional data was gathered retrospectively from each cooperating center.

resultsThe follow-up data for 79 cases from 11 centers were included. While being considered as FUOWFD: 100% were performed biochemistry and microbiology, 78.5% for rheumatological markers, 33% for oncological markers, and 97.5% for radiological investigations. Other medical departments were consulted in 64.5% of the cases and invasive diagnostic procedures were performed in 27.8%. During the follow-up, 73 cases (92.4%) saw their fever resolve. Among these, 70 cases' fever resolved within the first three months. In total, two patients (2.5%) received a definitive diagnosis during the follow-up period. After 6 months and 12 months follow up, the all-cause mortality rate was 3.8%. Notably, none of the three cases that experienced mortality by day 365 had received a final diagnosis for FUO.

conclusionThe diagnostic process for FUO cases who remain undiagnosed exhibits substantial heterogeneity. The majority of patients experience spontaneous recovery, and the mortality rate is relatively low. Infectious causes are the most frequently encountered contributors to the FUO cases who remain undiagnosed. CLINICAL TRIAL NUMBER: Not applicable.

Indexed as

Communicable DiseasesFever of Unknown OriginAdultAgedAged, 80 and overFemaleFollow-Up StudiesHumansMaleMiddle AgedRetrospective StudiesFever of unknown originFUOPUOPyrexia of unknown originUndiagnosed

Identifiers

PMID42115988
PMCPMC13335332

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Registered trials

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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.