Impact factors of severe/critical conditions among SARS-CoV-2 Omicron variant infected patients aged 60 years and above: a hospital records-based analysis

  Objective  To analyze influence factors of severe/critical conditions among elderly patients ( ≥ 60 years) infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant.

  Methods  Medical records of all elderly patients (≥ 60 years) with SARS-CoV-2 Omicron variant infection during April 6 – June 12, 2022 were extracted from a designated hospital for coronavirus disease 2019 (COVID-19) in Shanghai city and the patients were assigned into different severity groups according to their clinical conditions. Univariate and multivariate logistic regression analysis were adopted in analysis on factors associated with clinical severity in the patents.

  Results  Of the 625 patients included in the study, 455, 125, and 45 were mild, common, and severe/critical cases. In the patients, the proportion of severe/critical cases increased significantly by age, with the proportions of 2.99% (7/234), 7.34% (13/177), 9.03% (13/144), and 17.14% (12/70) for the patients aged 60 – 69, 70 – 79, 80 – 89, ≥ 90 years (χ²_trend = 8.288, P = 0.004); the proportion also significantly increased inversely with the dose number of COVID-19 vaccination, with the proportions of 2.33% (1/43), 1.35% (1/74), 6.98% (3/43), and 8.60% (40/465) for the patients having 3, 2, 1, and zero dose vaccine, respectively (χ²_trend = 10.201, P = 0.001). The results of multivariate logistic regression analysis showed that at older age (odds ratio OR = 1.606, 95% confidence interval 95% CI: 1.177 – 2.192) and suffering from diabetes (OR = 1.916, 95% CI: 1.030 – 3.565) were independent risk factors for severe/critical conditions.

  Conclusion  For SARS-CoV-2 Omicron variant infected patients over 60 years old, advanced age and having diabetes are risk factors for severe/critical conditions and vaccination could effectively reduce that risk.