Analysis of death risk factors among COVID-19 patients in Yazd, Iran: A case-cohort study.

Background: The COVID-19 epidemic control has become a global challenge and many contributing variables are still unknown to policymakers. This case-cohort study was conducted to investigate the risk factors of mortality in COVID-19 patients. Methods: This case-cohort study was conducted on 956 samples in Ardakan and Meybod counties, Yazd Province, between February 20 and May 20, 2020. The data collection tool was a researcher-made questionnaire. Data analysis was done using descriptive statistics and paired t-test, chi-square, and logistic regression analysis. Results: Of a total cohort population of 993 in Ardakan and Meybod counties, 435 were assigned to the control group and 521 were assigned to the case group. The results of outcome analysis showed that 14.4% of the patients in the case group and 11.5% of the patients in the control group died. According to the results of logistic regression analysis in COVID-19 patients, each one-year increase in age increased the risk of mortality by 6% (HR = 1.06, p < 0.001), each one-day increase in the hospital stay increased the risk of death by 8% (HR = 1.08, p < 0.001). Moreover, the presence of cardiovascular disease, chronic neurological disease, and chronic pulmonary disease increased the risk of death. The patients who underwent mechanical ventilation had 85% less chance of survival (HR = 0.15, p < 0.001). Conclusions: The results showed a higher mortality rate in the elderly patients as well as those with underlying diseases. Attention should be paid to at-risk and elderly patients in terms of ensuring a healthy diet, improving their self-care practices, and providing long-term medical and healthcare facilities.