Investigating the factors affecting the survival rate in patients with COVID-19: A retrospective cohort study

Background: As hospitalized patients with COVID-19, especially those who are admitted to ICU or die afterwards, generally have comorbidities, the aim of this study was to determine the factors affecting the survival rate of COVID-19 patients in Iran using a retrospective cohort. Methods: This retrospective cohort study was conducted on patients with COVID-19 who referred to medical centers under the supervision of Iran University of Medical Sciences, Tehran, Iran, from February 22 to March 25, 2020. The final date of follow-up was April 19, 2020. All consecutive inpatients with laboratory-confirmed COVID-19 were included in this study. Clinical laboratory, radiological, treatment, and demographic data were collected and analyzed. The associations among gender, immune disease, diabetes, liver disease, cardiovascular disease, kidney disease, chronic pulmonary disease, cancer, chronic nervous disease, type of treatment, and risk of death were analyzed. The Kaplan-Meier and Log-rank tests were used to estimate survival rate and compare survival rates, respectively. Results: The total number of deaths or desired event in the study was 329 (10.3%).The risk of death in the age groups of 50-60 years, 60-70 years, and >70 years compared to the 30-40 age group was 2.17 (95% CI: 1.03, 4.55; p: 0.040); 3.72 (95 % CI: 1.80, 7.68; p: 0.001) and 5.09 (95 % CI: 2.49, 10.40; p: 0.001), respectively. The results showed men had 11.5% more risk of deaths than women (HR: 1.11; 95 % CI: 0.89, 1.39; p: 0.341). Kidney disease increased the risk of death by 52.3% in these patients, which was not statistically significant (HR: 1.78; 95 % CI: 1.04, 3.04; p: 0.035). Also, chronic pulmonary diseases and diabetes increased the risk of death in COVID-19 patients by 89.5% and 41.3% compared to COVID-19 patients without chronic pulmonary diseases and diabetes [(HR: 1.89; 95 % CI: 1.17, 3.04; p: 0.008), (HR: 1.41; 95 % CI: 1.01, 1.96; p: 0.038)]. Conclusion: Based on the results of this study, more attention and care should be paid to COVID-19 patients with underlying diseases, such as chronic obstructive pulmonary disease, diabetes, and kidney disease to reduce the number of deaths.