Du Peipei, Cao Peihua, Yan Xiaodong, He Daihai, Zhang Xiaotong, Chen Weixiang, Luo Jiawei, Zeng Ziqian, Chen Yaolong, Yang Lin, Yang Shu, Feng Xixi
School of Public Health, Chengdu Medical College, Chengdu, People's Republic of China.
College of Medical Information Engineering, Chengdu University of Traditional Chinese Medicine, Chengdu, People's Republic of China.
J Appl Stat. 2021 Jul 8;50(11-12):2504-2517. doi: 10.1080/02664763.2021.1947995. eCollection 2023.
The difference in age structure and aging population level was an important factor that caused the difference in COVID-19's case fatality rate (CFR) in various regions. To eliminate the age effect on estimating the CFR of COVID-19, our study applied nonlinear logistic model and maximum likelihood method to fit the age-fatality curves of COVID-19 in different countries and regions. We further computed the standardized mortality ratio from the age-fatality curves of COVID-19 in the above regions and found that the risk of COVID-19 death in Wuhan was of a moderate level, while the non-Hubei region was even lower, compared with other regions. Regarding the disparity of CFRs among different regions in the country, we believed that there might be an unascertained phenomenon in high-endemic regions. Based on age-fatality rate curves, we estimated unascertained rates in cities with severe epidemics such as Wuhan and New York, and it was found that the total unascertained rates in Wuhan and New York were 81.6% and 81.2%, respectively. Meanwhile, we also found that the unascertained rates varied greatly with age.
年龄结构和老龄化人口水平的差异是导致不同地区新冠病毒病病死率（CFR）存在差异的重要因素。为消除年龄因素对新冠病毒病病死率估算的影响，本研究应用非线性逻辑模型和最大似然法拟合不同国家和地区新冠病毒病的年龄-死亡曲线。我们进一步根据上述地区新冠病毒病的年龄-死亡曲线计算标准化死亡率，发现武汉新冠病毒病死亡风险处于中等水平，与其他地区相比，非湖北地区甚至更低。关于国内不同地区病死率的差异，我们认为高流行地区可能存在未确诊现象。基于年龄-病死率曲线，我们估算了武汉和纽约等疫情严重城市的未确诊率，发现武汉和纽约的总未确诊率分别为81.6%和81.2%。同时，我们还发现未确诊率随年龄变化差异很大。
