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. 2021 Jul 16;21(1):685.
doi: 10.1186/s12879-021-06378-z.

High risk groups for severe COVID-19 in a whole of population cohort in Australia

Bette Liu  1   2 , Paula Spokes  3 , Wenqiang He  4 , John Kaldor  5
Affiliations

High risk groups for severe COVID-19 in a whole of population cohort in Australia

Bette Liu et al. BMC Infect Dis. .

Abstract

Background: Increasing age is the strongest known risk factor for severe COVID-19 disease but information on other factors is more limited.

Methods: All cases of COVID-19 diagnosed from January-October 2020 in New South Wales Australia were followed for COVID-19-related hospitalisations, intensive care unit (ICU) admissions and deaths through record linkage. Adjusted hazard ratios (aHR) for severe COVID-19 disease, measured by hospitalisation or death, or very severe COVID-19, measured by ICU admission or death according to age, sex, socioeconomic status and co-morbidities were estimated.

Results: Of 4054 confirmed cases, 468 (11.5%) were classified as having severe COVID-19 and 190 (4.7%) as having very severe disease. After adjusting for sex, socioeconomic status and comorbidities, increasing age led to the greatest risk of very severe disease. Compared to those 30-39 years, the aHR for ICU or death from COVID-19 was 4.45 in those 70-79 years; 8.43 in those 80-89 years; 16.19 in those 90+ years. After age, relative risks for very severe disease associated with other factors were more moderate: males vs females aHR 1.40 (95%CI 1.04-1.88); immunosuppressive conditions vs none aHR 2.20 (1.35-3.57); diabetes vs none aHR 1.88 (1.33-2.67); chronic lung disease vs none aHR 1.68 (1.18-2.38); obesity vs not obese aHR 1.52 (1.05-2.21). More comorbidities was associated with significantly greater risk; comparing those with 3+ comorbidities to those with none, aHR 5.34 (3.15-9.04).

Conclusions: In a setting with high COVID-19 case ascertainment and almost complete case follow-up, we found the risk of very severe disease varies by age, sex and presence of comorbidities. This variation should be considered in targeting prevention strategies.

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Conflict of interest statement

The authors have no competing interests as defined by BMC, or other interests that might be perceived to influence the results and/or discussion reported in this paper.

Figures

Fig. 1
Fig. 1
Kaplan Meier survival curve for time to a hospitisation or death and b ICU admission or death according to age
Fig. 2
Fig. 2
Hazard ratios for risk of severe COVID-19 (hospitalisation or death) according to age and other sociodemographic characteristics
Fig. 3
Fig. 3
Hazard ratios for risk of severe COVID-19 (hospitalisation or death) according to co-morbidities and other factors compared to those without each comorbidity
Fig. 4
Fig. 4
Hazard ratios for risk of very severe COVID-19 (ICU admission or death) according to sociodemographic characteristics
Fig. 5
Fig. 5
Hazard ratios for risk of very severe COVID-19 (ICU admission or death) according to co-morbidities and other factors compared to those without each comorbidity
Fig. 6
Fig. 6
Hazard ratios for risk of severe (hospitalisation or death) and very severe (ICU or death) COVID-19 according to number of comorbidities
See this image and copyright information in PMC

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