Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Mar:20:100365.
doi: 10.1016/j.lanwpc.2021.100365. Epub 2022 Jan 2.

Comparison of patient characteristics and in-hospital mortality between patients with COVID-19 in 2020 and those with influenza in 2017-2020: a multicenter, retrospective cohort study in Japan

Yuta Taniguchi  1   2 , Toshiki Kuno  3 , Jun Komiyama  1 , Motohiko Adomi  1 , Toshiki Suzuki  4 , Toshikazu Abe  2   5 , Miho Ishimaru  6 , Atsushi Miyawaki  2   7   8 , Makoto Saito  9 , Hiroyuki Ohbe  10 , Yoshihisa Miyamoto  11 , Shinobu Imai  12 , Tadashi Kamio  13 , Nanako Tamiya  2   6 , Masao Iwagami  2   6   14
Affiliations

Comparison of patient characteristics and in-hospital mortality between patients with COVID-19 in 2020 and those with influenza in 2017-2020: a multicenter, retrospective cohort study in Japan

Yuta Taniguchi et al. Lancet Reg Health West Pac. 2022 Mar.

Abstract

Background: COVID-19 has worse mortality than influenza in American and European studies, but evidence from the Western Pacific region is scarce.

Methods: Using a large-scale multicenter inpatient claims data in Japan, we identified individuals hospitalised with COVID-19 in 2020 or influenza in 2017-2020. We compared patient characteristics, supportive care, and in-hospital mortality, with multivariable logistic regression analyses for in-hospital mortality overall, by age group, and among patients with mechanical ventilation.

Findings: We identified 16,790 COVID-19 patients and 27,870 influenza patients, with the different age distribution (peak at 70-89 years in COVID-19 vs. bimodal peaks at 0-9 and 80-89 years in influenza). On admission, the use of mechanical ventilation was similar in both groups (1·4% vs. 1·4%) but higher in the COVID-19 group (3·3% vs. 2·5%; p<0·0001) during the entire hospitalisation. The crude in-hospital mortality was 5·1% (856/16,790) for COVID-19 and 2·8% (791/27,870) for influenza. Adjusted for potential confounders, the in-hospital mortality was higher for COVID-19 than for influenza (adjusted odds ratio [aOR] 1·83, 95% confidence interval [CI] 1·64-2·04). In age-stratified analyses, the aOR (95%CI) were 0·78 (0·56-1·08) and 2·05 (1·83-2·30) in patients aged 20-69 years and ≥70 years, respectively (p-for-interaction<0·0001). Among patients with mechanical ventilation, the aOR was 0·79 (0·59-1·05).

Interpretation: Patients hospitalised with COVID-19 in Japan were more likely to die than those with influenza. However, this was mainly driven by findings in older people, and there was no difference once mechanical ventilation was started.

Funding: Ministry of Health, Labour and Welfare of Japan (21AA2007).

PubMed Disclaimer

Conflict of interest statement

Atsushi Miyawaki has a joint research project with Medical Data Vision Co., Ltd. outside of this study and received labour contributions in the financial year 2020.

Figures

Figure 1
Figure 1
Distribution of patients admitted for COVID-19 in 2020 or influenza in 2017–2020 by calendar month of admission.
Figure 2
Figure 2
Distribution of patients admitted for COVID-19 in 2020 or influenza in 2017–2020 by age.
Figure 3
Figure 3
In-hospital death of patients admitted for COVID-19 in 2020 or influenza in 2017–2020 by age.
See this image and copyright information in PMC

References

    1. World Health Organization. WHO Coronavirus (COVID-19) dashboard.; https://covid19.who.int. Accessed Novermber 20, 2021.
    1. Jiang C, Yao X, Zhao Y, et al. Comparative review of respiratory diseases caused by coronaviruses and influenza A viruses during epidemic season. Microbes Infect. 2020;22(6–7):236–244. - PMC - PubMed
    1. Xie Y, Bowe B, Maddukuri G, Al-Aly Z. Comparative evaluation of clinical manifestations and risk of death in patients admitted to hospital with COVID-19 and seasonal influenza: cohort study. BMJ. 2020;371:m4677. - PMC - PubMed
    1. Piroth L, Cottenet J, Mariet AS, et al. Comparison of the characteristics, morbidity, and mortality of COVID-19 and seasonal influenza: a nationwide, population-based retrospective cohort study. Lancet Respir Med. 2021;9(3):251–259. - PMC - PubMed
    1. Brehm TT, van der Meirschen M, Hennigs A, et al. Comparison of clinical characteristics and disease outcome of COVID-19 and seasonal influenza. Sci Rep. 2021;11(1):5803. - PMC - PubMed