Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy -
Cystic Fibrosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy -
Panminerva Med. 2022 Dec;64(4):472-478. doi: 10.23736/S0031-0808.21.04397-4. Epub 2021 Apr 28.
Differences between total deaths registered during the COVID-19 pandemic and those registered in a previous reference period are the most frequently used measures of the pandemic effect. However, these measures do not consider demographic changes and temporal trends in mortality. In this study we estimated the excess mortality in 2020 in Italy considering demographic changes and temporal trends in mortality.
We used daily mortality and population data for the 2011-2019 period to estimate the expected deaths in 2020. Expected deaths were estimated, separately by sex, through an overdispersed Poisson regression model including calendar year and age group as covariates, a smooth function of the year's week, and the logarithm of the population as offset. The difference between observed and expected deaths was considered a measure of excess mortality.
In 2020, 746,146 deaths occurred in Italy. We estimated an excess mortality of 90,725 deaths (95% CI: 86,503-94,914), which became 99,289 deaths after excluding January and February, when mortality was lower than expected. The excess was higher among men (49,422 deaths) than women (41,303 deaths) and it was mostly detected at ages ≥80 (60,224 deaths) and ages 65-79 (25,791 deaths), while among the population aged 25-49 and 50-64 we estimated an excess of 281 and 4764 deaths, respectively.
After considering demographic changes and temporal improvement in mortality the excess deaths in 2020 still remains above 90,000 deaths. More important, considering these factors, the excess at ages <80 years is revised upwards, while the excess at older ages is revised downwards.
新冠大流行期间登记的总死亡人数与前一参考期登记的总死亡人数之间的差异是衡量大流行影响最常用的指标。然而，这些措施没有考虑人口变化和死亡率的时间趋势。在这项研究中，我们考虑了人口变化和死亡率的时间趋势，估计了 2020 年意大利的超额死亡率。
我们使用 2011-2019 年期间的每日死亡率和人口数据来估计 2020 年的预期死亡人数。通过包含日历年份和年龄组作为协变量、一年中周的平滑函数以及人口对数作为偏移量的过离散泊松回归模型，分别按性别估计预期死亡人数。观察到的死亡人数与预期死亡人数之间的差异被视为超额死亡人数的衡量标准。
2020 年，意大利有 746146 人死亡。我们估计超额死亡人数为 90725 人（95%CI：86503-94914），在排除了死亡率低于预期的 1 月和 2 月之后，这一数字上升至 99289 人。男性的超额死亡人数（49422 人）高于女性（41303 人），主要发生在年龄≥80 岁（60224 人）和 65-79 岁（25791 人），而在 25-49 岁和 50-64 岁的人群中，我们分别估计有 281 人和 4764 人超额死亡。
在考虑人口变化和死亡率的时间改善后，2020 年的超额死亡人数仍超过 9 万。更重要的是，考虑到这些因素，年龄<80 岁的超额死亡人数向上修正，而年龄较大的超额死亡人数向下修正。
