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What factors increase the risk of dying from COVID-19 ?

Text updated on 2020-05-25

Vulnerability factors that increase the risk of dying from COVID-19 are age and certain pre-existing diseases such as diabetes, hypertension, cardiovascular disease, obesity, or kidney failure.

The probability of an infected person dying from COVID-19 varies according to many parameters. The main parameters that have been identified to date for COVID-19 are age and the presence of certain pre-existing conditions (co-morbidity). With the advancement of our knowledge and the experience of caregivers, the likelihood of dying from COVID-19 tends to decrease.

Caution should be taken with the calculated estimates: they do not take into account undetected infected persons (not everyone is tested), nor infected persons whose survival/cure is still uncertain.

Age: Between the ages of 20 and 49, the risk of dying from COVID-19 for an infected person is very low and is not age-dependent. The risk of dying begins to increase from the age of 50 onwards. This age effect is observed in Asia, Europe, and North America. A person aged 80 years and over has about a 14% risk of dying from COVID-19 if they catch it. A 70-79 year old has a 3-8% chance of dying from it. Similar figures have been measured in China, Europe, and the United States.

Gender: Men have a higher risk than women (observed in Asia, Europe, and the United States). This sex effect is detected for people over 70 years of age.

Comorbidity: The risk of dying from COVID-19 for an infected person is higher if he or she has the following diseases: cardiovascular disease, diabetes, chronic respiratory disease, hypertension, cancer, kidney failure, cerebrovascular disease.

Overweight, obesity: People who are overweight or obese have a higher risk of developing a serious form of the disease.

Hospitalization for COVID-19: Peoplehospitalized for COVID-19 show severe forms of the disease. The analysis of 95,218 people hospitalized for COVID-19 in France indicates that, on average, 18% of patients hospitalized because of COVID-19 die. These figures vary from country to country depending on the saturation of resuscitation services, the age of the population, and co-morbidity factors in the population.

Cigarette: The data on tobacco are contradictory. Indeed, some studies suggest that smokers develop more severe respiratory symptoms while others indicate either no effect of smoking or even a protective effect (for example, in the case of sailors on the aircraft carrier, Charles de Gaulle). Further studies are needed to know the real effect of smoking.

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Analysis of 95,218 people hospitalised for coronavirus COVID-19 in France which led to 16,386 deaths: the probability of dying from coronavirus if infected is estimated at 8% for those aged 80 and over (about 6% for women and 14% for men) and 3% for those aged 70-79 (about 2% for women and 4% for men). On average, 18% of patients hospitalized for the disease COVID-19 die.

Salje, H., Kiem, C. T., Lefrancq, N., Courtejoie, N., Bosetti, P., Paireau, J., ... & Le Strat, Y. (2020). Estimating the burden of SARS-CoV-2 in France. Science eabc3517

Retrospective study of > 40,000 COVID cases in China. The case-fatality rate is higher in people with pre-existing co-morbidities is : 10.5% for cardiovascular disease, 7.3% for diabetes, 6.3% for chronic respiratory disease, 6.0% for hypertension, and 5.6% for cancer.

Wu, Z., & McGoogan, J. M. (2020). Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: summary of a report of 72 314 cases from the Chinese Center for Disease Control and Prevention. Jama, 323(13), 1239-1242.

Meta-analysis of COVID-19 cases in Chinese hospitals: older people or people with co-morbidities (diabetes, hypertension, cardiovascular or respiratory problems) were more likely to have severe symptoms.

Yang, J., Zheng, Y., Gou, X., Pu, K., Chen, Z., Guo, Q., ... Zhou, Y. (2020). Prevalence of comorbidities and its effects in patients infected with SARS-CoV-2: a systematic review and meta-analysis. International Journal of Infectious Diseases, 94, 91-95.

Retrospective study of > 44,000 cases COVID-19 in China: the probability of dying from coronavirus if infected for people aged 80 years and over is estimated at 14.8% and for those aged 70-79 years at 8%. A symptomatic SARS-CoV-2 positive adult who has no pre-existing medical problems ("co-morbidity") has a 0.9% probability of dying.

Vital Surveys (2020). The epidemiological characteristics of an outbreak of 2019 novel coronavirus diseases (COVID-19)-China, 2020. China CDC Weekly, 2(8), 113-122.

Study of the epidemic in Italy as of March 17, 2020: the probability of dying for people aged 80 and over with HIV COVID-19 was estimated at 20% and that of those aged 70-79 at 12.8%.

Onder, G., Rezza, G., & Brusaferro, S. (2020). Case-fatality rate and characteristics of patients dying in relation to COVID-19 in Italy. Jama.

Analysis of the epidemic in South Korea as of March 24, 2020: the probability of dying for people aged 80 years and older with COVID-19 was estimated at 13.6% and for those aged 70-79 years at 6.4%.

Kim, D. H., Choe, Y. J., & Jeong, J. Y. (2020). Understanding and interpretation of case fatality rate of coronavirus disease 2019. Journal of Korean Medical Science, 35(12).

Meta-analysis based on 33 studies showing an increased risk of developing severe symptoms (24 studies) or death (9 studies) COVID-19 in diabetic patients.

Kumar, A., Arora, A., Sharma, P., Anikhindi, S. A., Bansal, N., Singla, V., ... & Srivastava, A. (2020). Is diabetes mellitus associated with mortality and severity of COVID-19? A meta-analysis. Diabetes & Metabolic Syndrome: Clinical Research & Reviews.

Report of the Italian Institute of Health (Istituto Superiore della Sanità, ISS) revealing that 96% of the 29,692 patients who died in Italy on 14/05/2020 were carriers of at least one comorbidity: the most frequent were hypertension (68% of patients), cardiovascular diseases (67%), type 2 diabetes (31%), renal failure (21%), chronic obstructive pulmonary disease (17%), dementia (16%), cancer (active cancer in the last 5 years, 16%) and cerebrovascular diseases (11%) . In addition, 11% of the deceased were obese.

Characteristics of SARS-CoV-2 patients dying in Italy. Report based on available data on May 14th, 2020. Istituto Superiore di Sanità.

A Chinese study of 112 patients in intensive care COVID-19 shows that patients placed in intensive care had, on average, a higher Body Mass Index (BMI) than patients with a milder form of the disease. In addition, 88% of the patients who died were overweight (BMI > 25 Kg/m2) compared to 19% of the surviving patients.

Peng, Y. D., Meng, K., & Guan, H. Q. (2020). Clinical features and outcome of 112 cases of novel coronavirus pneumonia in cardiovascular patients. Chin J Cardiol, 48.

University of Lille study conducted on 124 COVID-19 patients admitted to intensive care showing that intubation is more often required in men and in people with obesity (BMI > 30 kg/m2) or severe obesity (BMI > 35 kg/m2), regardless of age, diabetes, or hypertension.

Simonnet, A., Chetboun, M., Poissy, J., Raverdy, V., Noulette, J., Duhamel, A., ... & Lille Intensive Care COVID-19 and Obesity study group. (2020). High prevalence of obesity in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) requiring invasive mechanical ventilation. Obesity.

A detailed analysis of the 29 serious cases of COVID-19 having required oxygenation on the aircraft carrier Charles de Gaulle (out of the 1766 people tested) shows that age as well as overweight are factors increasing the risk of developing a serious form of the disease. The 36-46 age group was 6 times more at risk of developing a serious form of the disease compared to younger sailors, a risk that was even more pronounced in the 46-60 age group. Seafarers who were overweight or obese (BMI ≥ 25 Kg/m2) were 3.5 times more likely to develop a severe form. On the other hand, being a smoker appeared to protect against the development of a serious form.

Ministry of the Armed Forces, Army Health Service. Investigation of the outbreak of COVID-19 within the Aeronaval Group, 21 January - 13 April 2020.

Fontanet, A., Shearer, L., Madec, Y., Grant, R., Besombes, C., Jolly, N., ... & Temmam, S. (2020). Cluster of COVID-19 in northern France: A retrospective closed cohort study. medRxiv.

Further reading

Who are the vulnerable people?