Background: The number of excess deaths in February-March 2020 in Italy, in comparison to the previous years, was considerably higher than recorded COVID19-related deaths. The present study is aimed at exploring the associations of excess mortality with some indices related to the epidemic and its management.
Methods: Data on all-cause mortality from February 20th to March 31st, in years from 2015 to 2020, and demographic, socioeconomic and healthcare organization data of each Italian region were obtained from Italian Institute of Statistics. Non-COVID19-Imputed Excess Mortality (NCIEM) was calculated as the difference between excess 2020 mortality and reported COVID19 mortality. The association of NCIEM with the rate of COVID-19 cases, COVID-19 mortality, and other potential moderators was assessed using linear regression models.
Results: The nationwide number of excess deaths, COVID-19 deaths was 26,701 and 13,710, respectively, with a difference of 12,991. NCIEM in different Regions showed a direct correlation with COVID-19 mortality (r2 = 0.61, p < 0.001) and total cases (r2 = 0.30, p = 0.012), and an inverse correlation with cases/total tests ratio (r2 = 0.49, p = 0.001). Direct correlations were also found with the proportion of institutionalized elderly, whereas inverse correlations were observed with prevalence of diabetes, cardiovascular mortality, and density of general practitioners.
Conclusions: The impact of the COVID19 epidemic on all-cause mortality is considerably greater than that indicated by official counts of victims. Limited testing capacity and causes of death other than COVID19 could contribute to the increase in overall mortality rates.