Temporal dynamics in total excess mortality and COVID-19 deaths in Italian cities

Abstract

Background: Standardized mortality surveillance data, capable of detecting variations in total mortality at population level and not only among the infected, provide an unbiased insight into the impact of epidemics, like COVID-19 (Coronavirus disease). We analysed the temporal trend in total excess mortality and deaths among positive cases of SARS-CoV-2 by geographical area (north and centre-south), age and sex, taking into account the deficit in mortality in previous months. Methods: Data from the Italian rapid mortality surveillance system was used to quantify excess deaths during the epidemic, to estimate the mortality deficit during the previous months and to compare total excess mortality with deaths among positive cases of SARS-CoV-2. Data were stratified by geographical area (north vs centre and south), age and sex. Results: COVID-19 had a greater impact in northern Italian cities among subjects aged 75-84 and 85+ years. COVID-19 deaths accounted for half of total excess mortality in both areas, with differences by age: almost all excess deaths were from COVID-19 among adults, while among the elderly only one third of the excess was coded as COVID-19. When taking into account the mortality deficit in the pre-pandemic period, different trends were observed by area: all excess mortality during COVID-19 was explained by deficit mortality in the centre and south, while only a 16% overlap was estimated in northern cities, with quotas decreasing by age, from 67% in the 15-64 years old to 1% only among subjects 85+ years old. Conclusions: An underestimation of COVID-19 deaths is particularly evident among the elderly. When quantifying the burden in mortality related to COVID-19, it is important to consider seasonal dynamics in mortality. Surveillance data provide an impartial indicator for monitoring the following phases of the epidemic, and may help in the evaluation of mitigation measures adopted.

Incidence and Death Rates from COVID-19 Are Not Always Coupled: An Analysis of Temporal Data on Local, Federal, and National Levels

“…Among the elderly population (>85 years) the percentage of non-COVID-19-caused excess mortality was reported to be 63%. Similar to our study, in Italy, excess mortality was negative within the first weeks of the year [ 26 ].…”

Patterns of COVID-19 related excess mortality in the municipalities of Northern Italy during the first wave of the pandemic

“…Comparing the epidemic period with the first five weeks of the year, in the large majority of municipalities of Lombardy and Emilia-Romagna, and to a lesser extent in Veneto, mortality in 2020 before the COVID-19 outbreak was lower than expected (data not shown). This trend has been observed in many countries worldwide ( EuroMOMO, 2020a ; 2020b ; Michelozzi et al, 2020 ; Vestergaard et al, 2020 ).…”

“…This can be likely attributed to a smaller incidence of deaths for causes such as accidents or occupational injuries, favored by the lockdown ( Zylke and Bauchner, 2020 ). On the other hand, the high mortality figures especially for people aged ≥75 may also have been increased by the lower incidence of influenza observed in Italy in the last winter compared to last year, which left more elderly people exposed to COVID-19 ( Bella, 2020 ; Michelozzi et al, 2020 ).…”

Gender specific excess mortality in Italy during the COVID-19 pandemic accounting for age

“…Thus, an excess of the overall mortality within a population can be an indicator of the impact of COVID-19. In Italy, data on excess mortality have been reported but only on a restricted number of cities or regions [ 2 , 3 ] or analyses have not accounted for age and sex standardisation [ 4 ]. The latter point is particularly important both from an epidemiological and a public health point of view.…”