Detection of outlier prefectures on the mortality due to COVID-19 in Japan

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Establishing a Competing Risk Regression Nomogram Model for Survival Data

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Kentaro Iwata1, Chisato Miyakoshi2

  • 1Division of Infectious Diseases, Kobe University Hospital, 7-5-2 Kusunokicho, Chuoku, Kobe, Japan.

Journal of Infection and Chemotherapy : Official Journal of the Japan Society of Chemotherapy
|January 26, 2023
PubMed

Insights

This study investigated COVID-19 mortality differences across Japanese prefectures. Hokkaido and Hyogo prefectures showed higher mortality rates than expected after accounting for key risk factors.

Area of Science:

  • Epidemiology
  • Public Health
  • Infectious Disease Research

Background:

  • Japan experienced significant COVID-19 mortality, with notable variations between prefectures.
  • Understanding these prefectural differences is crucial for targeted public health interventions.

Purpose of the Study:

  • To identify Japanese prefectures with COVID-19 mortality rates deviating from expected levels.
  • To analyze the association between COVID-19 mortality and factors like infection rates, population density, and elderly population proportion.

Main Methods:

  • Utilized multiple linear regression analyses to model COVID-19 mortality.
  • Employed the Hampel identifier to detect outlier prefectures.
  • Adjusted for key variables including number of infected cases, population density, and proportion of elderly population.

Main Results:

  • Hokkaido and Hyogo prefectures were identified as statistical outliers.
  • These prefectures exhibited higher COVID-19 mortality than predicted by the model.
  • The analysis adjusted for significant demographic and epidemiological factors.

Conclusions:

  • Prefectural variations in COVID-19 mortality exist in Japan beyond explained risk factors.
  • Hokkaido and Hyogo require further investigation to understand their elevated mortality.
  • Identifying specific causes for these outlier prefectural outcomes is essential for future pandemic preparedness.

Keywords:
COVID-19Hampel identifierJapanMortality

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