Characteristics and in-hospital mortality of patients with COVID-19 from the first to fifth waves of the pandemic in 2020 and 2021 in the Japanese Medical Data Vision database
Toshiki Suzuki,
Yuta Taniguchi,
Jun Komiyama,
Toshiki Kuno,
Motohiko Adomi,
Toshikazu Abe,
Ryota Inokuchi,
Atsushi Miyawaki,
Shinobu Imai,
Makoto Saito,
Hiroyuki Ohbe,
Shotaro Aso,
Tadashi Kamio,
Nanako Tamiya,
Masao Iwagami
Affiliations
Toshiki Suzuki
School of Medicine, University of Tsukuba, Tsukuba, Japan
Yuta Taniguchi
Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan; Health Services Research and Development Center, University of Tsukuba, Tsukuba, Japan
Jun Komiyama
Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan; Department of Health Services Research, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
Toshiki Kuno
Department of Cardiology, Montefiore Medical Center, Albert Einstein Medical College, NY, USA
Motohiko Adomi
Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
Toshikazu Abe
Health Services Research and Development Center, University of Tsukuba, Tsukuba, Japan; Department of Emergency and Critical Care Medicine, Tsukuba Memorial Hospital, Tsukuba, Japan
Ryota Inokuchi
Department of Health Services Research, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
Atsushi Miyawaki
Health Services Research and Development Center, University of Tsukuba, Tsukuba, Japan; Department of Public Health, Graduate School of Medicine, The University of, Tokyo, Tokyo, Japan
Shinobu Imai
Division of Pharmacoepidemiology, Department of Healthcare and Regulatory Sciences, Showa University School of Pharmacy, Tokyo, Japan
Makoto Saito
Division of Infectious Diseases, Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
Hiroyuki Ohbe
Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan
Shotaro Aso
Department of Real World Evidence, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
Tadashi Kamio
Division of Critical Care, Shonan Kamakura General Hospital, Kamakura, Kanagawa, Japan
Nanako Tamiya
Health Services Research and Development Center, University of Tsukuba, Tsukuba, Japan; Department of Health Services Research, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
Masao Iwagami
Health Services Research and Development Center, University of Tsukuba, Tsukuba, Japan; Department of Health Services Research, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan; Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK; Corresponding author. Department of Health Services Research, University of Tsukuba, Tsukuba, Japan.
Objectives: We aimed to describe patient characteristics, healthcare utilization, and in-hospital mortality among patients with COVID-19 in Japan across waves. Methods: Using a large-scale hospital-based database, we identified patients hospitalized for COVID-19 in the first (January–June 2020), second (June–October 2020), third (October 2020–February 2021), fourth (March–June 2021), and fifth (June–December 2021) waves. We summarized patient characteristics, healthcare utilization, and in-hospital mortality during each wave and performed multivariable logistic regression analyses for in-hospital mortality. Results: From the first to fifth waves, the number of patients (mean age ± standard deviation, years) was 2958 (61.2 ± 22.8), 7981 (55.6 ± 25.3), 18,788 (63.6 ± 22.9), 17,729 (60.6 ± 22.6), and 23,656 (51.2 ± 22.3), respectively. There were 190 (6.4%), 363 (4.5%), 1261 (6.7%), 1081 (6.1%), and 762 (3.2%) in-hospital deaths, respectively. The adjusted odds ratios for in-hospital deaths (95% confidence interval) were 0.78 (0.65–0.95), 0.94 (0.79–1.12), 0.99 (0.84–1.18), 0.77 (0.65–0.92), in the second to fifth waves, respectively, compared with the first wave. Conclusions: In-hospital COVID-19 mortality improved from the first to the second wave; however, during the third and fourth waves, mortality was as serious as in the first wave. Although in-hospital mortality during the fifth wave improved, careful monitoring is needed for upcoming waves, considering changing patient and viral characteristics.
