Investigation of the Factors Related to Mortality and Length of Hospitalization among COVID-19 Patients in East Azerbaijan Hospitals, Iran.

Background: It is of utmost importance to identify populations with an elevated risk for COVID-19 and the factors influencing its outcomes. The present study aimed to investigate factors affecting mortality and length of stay (LOS) among COVID-19 patients in the hospitals of East Azerbaijan province, Iran, during 15 months of this pandemic.

Study design: The present study followed a retrospective cohort design.

Methods: This retrospective study was conducted using data in the integrated syndromic surveillance system (ISSS) on patients admitted to the hospitals from February 21, 2020, to April 11, 2021. The association between variables of interest and death, as well as LOS, was investigated via multiple logistic regression and multiple linear regression analyses.

Results: In total, 24 293 inpatients with a mean age of 54.0 ± 19.4 years were included in this study. About 15% of them lost their lives, whose mean age was 69.0 ± 14.6 years, significantly higher than the recovered ones (P < 0.001). Factors, such as above 49 years of age (P < 0.001), male gender (OR = 1.17; 95% CI: 1.08-1.26), and having chronic diseases (OR = 1.32; 95% CI: 1.22-1.42), were correlated with patient mortality. In addition, having chronic diseases (Beta = 0.06; 95% CI: 0.03-0.08) was associated with higher LOS in hospitals.

Conclusion: In conclusion, older patients were at a higher risk of mortality and prolonged hospitalization. Furthermore, patients' underlying diseases could cause a severe form of COVID-19, which can lead to death and increase patients' LOS.