The study was conducted in Dire Dawa City Administration, located in the eastern part of Ethiopia. Dire Dawa is the nation’s second-largest city, with a population of over 535,686 as of 2022, according to projections by the Central Statistics Agency. It is situated approximately 515 km from Addis Ababa, the capital city, 55 km from Harar, and 300 km from Djibouti. The city is bordered by the Oromia and Somali regions.
Dire Dawa’s healthcare infrastructure includes two public hospitals, 16 health centers, and 36 health posts. All health centers in the area serve as testing sites for COVID-19 antigen detection rapid diagnostic tests (Ag-RDT), while the regional laboratory is responsible for conducting reverse transcription polymerase chain reaction (RT-PCR) tests. There are three designated COVID-19 treatment centers in the city: Sabian, Dilchora, and Ethio-France Hospitals.
Data was collected over a period from December 15, 2022, to January 15, 2023.
Study Design
The study employed a hospital-based unmatched case-control design.
Source population
The source population consisted of all laboratory-confirmed COVID-19 patients aged 18 years and older with chronic non-communicable diseases (NCDs) who were admitted to the treatment centers in Dire Dawa.
Study Population
The study population included laboratory-confirmed COVID-19 patients aged 18 years and older with chronic NCDs who were admitted to the treatment centers in Dire Dawa between June 1, 2020, and June 30, 2022.
Inclusion and Exclusion Criteria
Inclusion Criteria
Patients aged 18 years and above with chronic NCD who were tested COVID-19 positive by real time polymerase chain reaction (RT-PCR) or Antigen Rapid Diagnostic Test (Ag-RDT) and who were on treatment between June 1, 2020 and June 30, 2022.
Case
Confirmed COVID-19 patients aged 18 years and above with chronic NCD admitted to treatment centers and whose treatment outcome was death.
Control
Confirmed COVID-19 patients aged 18 years and above with chronic NCD admitted to treatment centers and whose treatment outcome was recovered (discharged alive).
Exclusion criteria
Patients with incomplete medical records on very important variables. (such as: date of admission, date of discharge, outcome status).
Patients who were died on arrival.
Sample Size Determination and Sampling Procedure
The sample size was determined using a formula for double population proportions and computed with Epi Info version 7.2.5.0 statistical software package. This calculation considered that 62.2% of controls and 77.6% of cases were exposed to shortness of breath. Assumptions for the study included a 95% confidence interval, 80% power, and a case-to-control ratio of 1:2. After adjusting for 10% missing data, the final sample size was determined to be 381 (127 cases and 254 controls).
The sampling procedure began by purposively selecting all three available COVID-19 treatment centers. Subsequently, the total sample size was distributed proportionally among these centers according to their patient load during the study period. Within each treatment center, patient charts were randomly selected using a simple random sampling technique. This selection process was conducted using a computer random number generating system in Excel and adhered to predetermined eligibility criteria.
Data collection tools and procedure
A data abstraction tool, comprising key variables of interest, was developed from registry records and adapted from various sources (16, 18, 19). It was comprehensively structured to encompass essential categories such as socio-demographic data, pre-existing comorbidities, clinical details, baseline vital signs, and crucial laboratory parameters. Prior to the commencement of data collection activities, all relevant stakeholders received a comprehensive briefing regarding the study's objectives, purpose, and significance.
The actual data collection was carried out by a team of four highly trained clinical nurses, each equipped with the necessary skills and expertise to extract data. They systematically reviewed medical records, meticulously extracting pertinent information from both the COVID-19 treatment register and patient charts. This exhaustive review spanned a substantial period from June 1, 2020, to June 30, 2022, ensuring a comprehensive scope of data collection.
To maintain the highest standards of accuracy and consistency, two experienced supervisors were assigned to oversee the entire data collection process. Their roles encompassed providing ongoing oversight, guidance, and support to the data collectors. Each supervisor was responsible for directly managing and monitoring the activities of two data collectors, ensuring adherence to the study protocol and the attainment of rigorous data collection standards
Variables
Dependent variable
COVID-19 in-hospital mortality
Independent variables
Socio-demography characteristics (age and sex),
Clinical characteristics (Pre-existing comorbidity, type of comorbidity, number of comorbidities, Severity of illness, presenting symptom),
Baseline vital sign and laboratory parameters (complete blood count and chemistry), and
Patient management (ICU admission, mechanical ventilation, and length of hospital stay).
Operational Definition
Moderate Illness
Individuals who show evidence of lower respiratory disease during clinical assessment or imaging and who have an oxygen saturation (SpO2) ≥ 94% on room air at sea level (20).
Severe Illness
Individuals who have SpO2 < 94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) < 300 mm Hg, a respiratory rate > 30 breaths/min, or lung infiltrates > 50% (20).
Critical Illness
Individuals who have respiratory failure, septic shock, and/or multiple organ dysfunction (20).
Discharge
Patient diagnosed with COVID-19 can be discharged when the symptoms have subsided, patients get stable and able to feed, and the body temperature remains at a normal range for at least three days without antipyretics, and two consecutive laboratory tests are negative collected ≥ 24 hours apart (21).
Death
COVID-19 death is defined for surveillance purposes as a death resulting from a clinically compatible illness in a probable or confirmed COVID-19 case, unless there is a clear alternative cause of death that cannot be related to COVID-19 disease (e.g. trauma). There should be no period of complete recovery between the illness and death (22).
Confirmed case
A person with laboratory confirmation of COVID-19 infection, irrespective of clinical signs and symptoms (23).
Chronic non-communicable diseases
A medical condition or disease that may be longer or of longer duration and is not transmitted from person to person (hypertension, diabetes mellitus, cardiac disease, chronic kidney disease, chronic lung disease and cancer (24).
Comorbidity
The co-existence of any of the concomitant chronic non-communicable diseases (hypertension, diabetes mellitus, cardiac disease, chronic kidney disease, chronic lung disease and cancer) with COVID-19 at the time of admission (Pal and Bhadada, 2020).
Length of hospital stay
is a clinical metric that measures the length of time elapsed between a patient's hospital admittance and discharge (25).
Dead on arrival
Refer to patients those who were declared dead upon arrival to an emergency department with no resuscitation attempt or those who died after failed resuscitation, usually within the first hour of arrival (26)
Data quality management
Data collectors and supervisors received training over a two-day on the data abstraction tool, data collection methods, and study protocols to ensure uniform understanding and adherence to standardized procedures. The data has been cleaned. Each completed data abstraction form underwent thorough review to verify data completeness. Any missing or incomplete entries were identified and addressed promptly. Consistency checks were performed to ensure uniformity of data elements with the original source from which it was obtained. A pretest was conducted on a randomly selected sample of 5% of charts at the Sabian COVID-19 treatment center. The purpose of this pretest was to assess the effectiveness of data collection procedures and to identify any potential issues or challenges. Following the pretest, amendments were made to enhance both the data collection tool and process, addressing any issues that were identified. Continuous close supervision and daily checking of the data collection process were carried out by supervisors and the principal investigator.
Data analysis
The extracted data were entered into Epi-data version 3.1 and analyzed using SPSS version 22 software. Data cleaning procedures were performed to identify and rectify any errors or inconsistencies in the dataset. Descriptive statistics, including frequencies and percentages for categorical variables, and mean with standard deviation (SD) or median with interquartile range (IQR) for continuous data, were computed based on data distribution. Normality assumptions were verified.
Baseline vital signs and laboratory parameters between cases and controls were compared using independent t-tests for normally distributed data and Mann-Whitney U tests for non-normally distributed data. A significance level of p < 0.05 was used to determine statistical significance.
Multicollinearity among independent variables was assessed using the variance inflation factor (VIF), with all VIF values ranging between 1.1 and 2.3, indicating no issues with multicollinearity. The adequacy of the final model was evaluated using the Hosmer and Lemeshow goodness of fit test, with a significance value of 0.13 indicating a good fit of the model to the data.
Bivariable analysis was conducted for each independent variable, and those with a p-value less than 0.25 were considered candidates for inclusion in the multivariable logistic regression model. In the multivariable analysis, adjusted odds ratios (AOR) with corresponding 95% confidence intervals (CI) were calculated to assess the strength of association between hospital mortality and predictor variables. The backward selection approach was applied, and variables with a p-value of < 0.05 were considered statistically significant
Ethical Considerations
The study received ethical approval from the Institutional Health Research Ethics Review Committee (IHRERC) of Haramaya University’s College of Health and Medical Sciences (Ethical Approval Number: IHRERC/214/2022), ensuring compliance with ethical standards for research involving human data. A support letter was obtained from the regional health bureau and submitted to the treatment centers, which granted permission to carry out the study. The research was conducted in accordance with the principles outlined in the Declaration of Helsinki, which governs research involving human data. As the study involved secondary data analysis without direct participant interaction, individual informed consent was not required. However, signed information sheets and informed voluntary consent were obtained from the heads of the respective hospitals, authorizing the use of data collected from their facilities. Data extraction was performed anonymously without patient identifying information to maintain the confidentiality of patient information.