Examination of all-cause mortalities and associated factors in patients diagnosed with covid-19 at Dokuz Eylül University Hospital

AIM: The aim of this study was to determine the all-cause mortality rate and examine the associated factors in individuals diagnosed with COVID-19 at Dokuz Eylul University Hospital between March 19, 2020, and May 31, 2021. METHOD: This study was conducted as a retrospective cohort study. The research took place at Dokuz Eylül University Hospital. The study group consisted of 8955 individuals aged 18 and over who applied to Dokuz Eylül University Hospital and were diagnosed with COVID-19 via PCR from March 19, 2020, to May 31, 2021. In this study, sociodemographic data, health status, and mortality data collected by DEÜ-COVIMER were utilized. The study did not involve sample selection, and an attempt was made to reach all patients. The independent variables of the study included age, gender, marital status, education, perceived economic status, alcohol consumption, smoking, presence of chronic diseases, and the number of chronic diseases, as well as the presence and number of pre-diagnosis complaints. The dependent variable of the study was all-cause mortality. Descriptive statistics were presented as counts and percentages for categorical variables and as median (IQR) for continuous variables. Survival analyses were used to investigate factors associated with all-cause mortality. For those who died, survival time was calculated as the period between the date of diagnosis and the date of death. For those who survived, survival time was calculated as the period between the date of the initial diagnosis and the last inquiry date (March 1, 2022) when the death status was last checked in the hospital information system. Kaplan-Meier survival curves were prepared, and survival times were compared using the Log-Rank test when comparing the categories of independent variables in terms of survival time. Cox Regression Models were constructed to examine the factors determining all-cause mortality. A forward variable selection method was employed in the analysis. When deciding on the variables to be included in the model, those that were statistically significant in the Kaplan-Meier analyses were taken into account. The analyses were conducted using SPSS software version 26. A two-tailed p-value of <0.05 was considered statistically significant. RESULTS: The median age of the study group of 8,955 individuals was 42 (IQR: 31-55). Of the patients, 51.2% were female, and 48.8% were male. During the median follow-up period of 452 days (range: 330-482 days), 421 (4.7%) patients died. Among these cases, 261 (61.9%) died during their initial admission to Dokuz Eylul University Hospital, while 160 (39.1%) died after being discharged from the hospital. A total of 259 (2.9%) patients died within 28 days (early), while 162 (1.8%) patients died after 28 days (late). All-cause mortality was lower among patients treated at home (0.8%) compared to those hospitalized in regular wards (12.0%) and intensive care units (72.2%). Age, being male, lower educational level, the presence of chronic illnesses, an increase in the number of chronic illnesses, not consuming alcohol, smoking, the absence of pre-diagnosis complaints, an increase in pre-diagnosis complaints, and admission to intensive care and regular wards were found to significantly shorten survival times (p <0.001). Marital status (p=0.319) and perceived economic status (p=0.271) were not found to influence survival. In the multivariable Cox regression model adjusted for all factors included in the model, the risk of all-cause mortality was found to be higher in individuals aged 80 and over compared to those aged 50 and under (aHR: 20.9; 95% CI: 10.1-43.0). The risk of all-cause mortality was higher in those who had quit smoking or were still smoking compared to non-smokers (aHR: 1.6; 95% CI: 1.2-2.3). The absence of pre-diagnosis complaints was associated with an increased risk of all-cause mortality compared to those with 3 or more complaints (aHR: 1.5; 95% CI: 1.1-2.2). Patients admitted to intensive care had a higher risk of all-cause mortality (aHR: 58.0; 95% CI: 36.5-96.1) compared to outpatients. CONCLUSION: In COVID-19 patients, the risk of all-cause mortality was increased by being male, older age, lower educational attainment, pre-existing chronic diseases, alcohol consumption, smoking, pre-diagnostic complaints, and initial admission to intensive care or a regular ward. High-risk groups should be prioritized for early diagnosis, monitoring, and treatment. Health policies should be designed to manage the pandemic effectively by considering these risk factors and allocating resources accordingly. KEY WORDS: COVID-19, Mortality, Cohort Study