Evidence map›Paper›PMID 41506776›Full record

Observational studyBMJ open2026

Clinical characteristics, treatments and outcomes of hospitalised COVID-19 patients across pandemic waves at a tertiary acute care hospital in Narita, Japan: a single-centre retrospective observational study.

Ryota Hase, Rika Kurata, Yu Niiyama, Naoya Matsuda, Hideki Ueda, Koki Kikuchi, Keiko Ishida, Yoshifumi Kubota, Motoki Fujii, Takashi Kurita and 11 more

Abstract readObservational Study
In one paragraph

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

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
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

21 authors.

Ryota HaseDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan ryota.hase@naritasekijyuji.jp.ORCID http://orcid.org/0000-0002-3135-1757
Rika KurataDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Yu NiiyamaDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Naoya MatsudaDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Hideki UedaDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Koki KikuchiDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Keiko IshidaDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Yoshifumi KubotaDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Motoki FujiiDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Takashi KuritaDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Emiri MuranakaDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Hiroki SasazawaDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Haruki MitoDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Yudai YanoDepartment of Infectious Diseases, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Reiko OkuDepartment of Emergency and Critical Care Medicine, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Yoshihisa TateishiDepartment of Emergency and Critical Care Medicine, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Satoshi ToishiDepartment of Neonatology, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Shintaro ObataDepartment of Obstetrics and Gynecology, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Yasushi NoguchiDepartment of Pediatrics, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Kazuya NakanishiDepartment of Emergency and Critical Care Medicine, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.
Shosuke SunamiDepartment of Pediatrics, Japanese Red Cross Narita Hospital, Narita, Chiba, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectiveThis study aims to describe the characteristics of hospitalised COVID-19 patients in a tertiary care hospital close to an international airport in Japan and to compare these characteristics among different waves during the pandemic.

designRetrospective observational study.

settingTertiary care centre in Japan.

participantsAll patients diagnosed with COVID-19 who were hospitalised between January 2020 and April 2022 were included. MEASUREMENTS: Clinical characteristics, characteristics of admission, treatments and outcomes were investigated and compared among six pandemic waves.

resultsA total of 827 patients were included. The median age was 58.0 years. More than half of the patients (58.3%) had at least one comorbidity. The majority of patients (89.0%) were domestically infected patients admitted under the Infectious Diseases Law, while the remaining patients (11.0%) were those diagnosed during airport quarantine and admitted under the Quarantine Act. Hospital-acquired COVID-19 infection occurred in 7.0% of cases, and mainly during the sixth wave. Overall, some form of oxygen therapy, high-flow oxygen devices, invasive mechanical ventilation (IMV) and extracorporeal membrane oxygenation was provided in 46.3%, 10.4%, 4.5% and 1.5% of cases, respectively. Only 1.8% of patients were treated in the intensive care unit (ICU), and 59.5% of patients on IMV were managed in the non-ICU ward. The in-hospital mortality rate was 5.8%. Median age, percentages of some comorbidities, vaccination coverage, medications for COVID-19, types of supportive care and ICU admissions differed significantly among waves.

conclusionsThis study suggests that patient characteristics, vaccination coverage, standard of treatment and severity of illness changed across waves during the COVID-19 pandemic. Intensive care delivery in non-ICU wards was unavoidable due to limited ICU capacity, which may be a key consideration when preparing for future pandemics.

Indexed as

COVID-19HospitalizationAdultAgedFemaleHumansJapanMaleMiddle AgedPandemicsRespiration, ArtificialRetrospective StudiesSARS-CoV-2Tertiary Care CentersCOVID-19HospitalizationINFECTIOUS DISEASESObservational StudySARS-CoV-2 Infection

Identifiers

PMID41506776
PMCPMC13059877

What OpenQuestion holds

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LicenceCC BY-NC
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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.