Excess mortality during the COVID-19 outbreak in Italy: a two-stage interrupted time-series analysis

Int J Epidemiol. 2021 Jan 23;49(6):1909-1917. doi: 10.1093/ije/dyaa169.


Background: Italy was the first country outside China to experience the impact of the COVID-19 pandemic, which resulted in a significant health burden. This study presents an analysis of the excess mortality across the 107 Italian provinces, stratified by sex, age group and period of the outbreak.

Methods: The analysis was performed using a two-stage interrupted time-series design using daily mortality data for the period January 2015-May 2020. In the first stage, we performed province-level quasi-Poisson regression models, with smooth functions to define a baseline risk while accounting for trends and weather conditions and to flexibly estimate the variation in excess risk during the outbreak. Estimates were pooled in the second stage using a mixed-effects multivariate meta-analysis.

Results: In the period 15 February-15 May 2020, we estimated an excess of 47 490 [95% empirical confidence intervals (eCIs): 43 984 to 50 362] deaths in Italy, corresponding to an increase of 29.5% (95% eCI: 26.8 to 31.9%) from the expected mortality. The analysis indicates a strong geographical pattern, with the majority of excess deaths occurring in northern regions, where few provinces experienced increases up to 800% during the peak in late March. There were differences by sex, age and area both in the overall impact and in its temporal distribution.

Conclusion: This study offers a detailed picture of excess mortality during the first months of the COVID-19 pandemic in Italy. The strong geographical and temporal patterns can be related to the implementation of lockdown policies and multiple direct and indirect pathways in mortality risk.

Keywords: COVID-19; Italy; SARS-CoV-2; epidemic; interrupted time series; mortality.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • COVID-19 / mortality*
  • Communicable Disease Control
  • Disease Outbreaks*
  • Female
  • Humans
  • Interrupted Time Series Analysis
  • Italy / epidemiology
  • Male
  • Middle Aged
  • Mortality / trends*
  • Pandemics*
  • SARS-CoV-2*