This was a descriptive retrospective study on patients infected with SARS-CoV-2 who were admitted to the CTEs from August 1, 2020, to June 30, 2021.

The study population consisted of patients infected with SARS-CoV-2 who were admitted to CTEs with at least one comorbidity during the study period.

All patients with at least one positive COVID-19 PCR on admission and at least one associated comorbidity whose records were available, were included in the study.

Patients with very little information in their records were excluded.

This was a non-probabilistic convenience sampling, with exhaustive and systematic census of all medical records of patients meeting our criteria.

Data collection was conducted through document review, specifically the patients’ medical records. A digital data extraction form was created using the KoboCollect app to facilitate data collection via smartphones. Data collection began following the issuing of a research authorization granted by the Minister of Health on August 31, 2021, under number 2634/MS/DC/SGM/DRFMT/SRAO/SA. With the recruited agents, we proceeded to review the records. During the collection process, we systematically checked each completed electronic form daily to minimize information bias.

The variables examined in this study are as follows:

- Sociodemographic Variables (age, gender, occupation, education level, ethnicity, origin, marital status);

- variables relating to clinical parameters (comorbidities, functional signs, general signs, physical signs);

- variables relating to therapeutic data (admission time, length of hospitalization, adherence to the therapeutic protocol, resuscitation materials used, treatment progress).

The completeness and coherence of the collected data were verified daily. Data were processed and analyzed using Stata 15 software. Quantitative variables were expressed as mean with standard deviation when the distribution was normal, and by the median with interquartile range (Q1; Q3) when the distribution was asymmetric (assessed by the Shapiro-Wilk test). Qualitative variables were expressed in headcounts and percentages.

In accordance with the principle of medical confidentiality, confidentiality was rigorously maintained throughout the survey. The anonymity and confidentiality of patient records were guaranteed through an anonymous identification system of forms. The collected data were used solely for the purpose of this study [9] .

Out of 819 hospitalized patients during the study period, 516 patients had at least one comorbidity. The hospital prevalence of comorbidities among patients infected with SARS-CoV-2 in CTE over the period of August 2020 to June 2021 was 63%.

The average age of patients was 57.25 ± 15.77 years, with extremes ranging from 5 months to 92 years. The age group of 45 years and over accounted for 81.97%.

Males were predominant, with 298 men and 218 women, resulting in a sex ratio (M/F) of 1.37. The majority of patients, 97.87%, resided in Benin. Regarding the department of origin, the littoral department was the most represented. In fact, 168 patients (33.27%) came from this department. This information was not provided for 128 patients, representing 23.17% of the total. Table 1 shows the distribution of patients infected with SARS-CoV-2 with at least one comorbidity in CTE according to age, gender, country of origin, and department of origin.

In the vast majority of cases, ethnicity was not reported. There were 359 patients (69.57%) for whom this data was missing. 79 patients (15.31%) were of Fon ethnicity. For 336 patients (65.12%), the marital status was not specified; 145 patients (28.1%) were married. For 345 patients (66.86%), the education level was not reported; 112 patients (1.71%) had a university level. For 156 patients (30.23%), the profession was not specified; 85 patients (16.47%) were civil servants. Table 2 shows the distribution of patients infected with SARS-CoV-2 with at least one comorbidity in CTE according to marital status, occupation, ethnicity, and education level.

*: 04 patients coming from France, 02 from Nigeria, 02 from DRC, 01 from Niger, 01 from Ghana and 01 from Maroc.

Patients admitted to the CTE mostly had associated pathologies, arterial hypertension followed by diabetes and obesity. These comorbidities were respectively found in 68.60%, 40.31%, and 11.05% of the patients. Table 3 shows the distribution of patients infected with SARS-CoV-2 with at least one comorbidity in CTE according to comorbidity.

*: Among the other comorbidities, we have two (02) cases of severe acute malnutrition, two (02) cases of rheumatoid arthritis, one (01) case of superficial second-degree burns, one (01) case of Down syndrome, one (01) case of tetralogy of Fallot, one (01) case of chronic prostatitis, one (01) case of cranioencephalic trauma from a public road accident, one (01) case of chronic inflammatory bowel disease, one (01) case of hyperthyroidism, and one (01) case of vitiligo.

The dominant functional symptoms in the study were respectively: asthenia (57.56%), fever (51.55%), dyspnea (45.93%), cough (45.16%), anorexia (20.35%), rhinorrhea (11.24%), cephalalgia (10.08%), myalgia (8.53%), and anosmia (6.59%).

Only 188 patients (36.43%) were in good general condition on admission; 307 (59.50%) had an admission heart rate >20 cycles per minute; 83 (16.09%) had a temperature >37.8˚C; 132 (25.58%) had a heart rate >100 beats per minute and 245 (47.48%) had a pulse oxygen saturation percentage <95%. Table 4 shows the distribution of patients infected with SARS-CoV-2 with at least one comorbidity according to general signs on admission.

The average admission time was 6.17 days, with extremes ranging from around one (01) hour to 60 days.

The average length of hospitalization was 11.06 days, with extremes ranging from 30 minutes to 70 days. Table 5 shows the distribution of patients infected with SARS-CoV-2 with at least one comorbidity in the CTE according to admission time and length of hospitalization.

In the CTE, 270 patients (52.33%) were on oxygen therapy by mask or scope, 15 (2.91%) had endotracheal intubation, 38 (7.36%) were on non-invasive ventilation and 208 had not used any resuscitation equipment. Table 6 shows the distribution of patients infected with SARS-CoV-2 with at least one comorbidity according to resuscitation materials used.

The therapeutic care of patients infected with SARS-CoV-2 on admission to the CTE was based on protocol 1 (using chloroquine) for simple and moderate cases, on protocol 2 (using antiretrovirals) for severe cases, and on a mixed protocol. More than half of the patients, or 58.53% (302), were treated using protocol 2, 39.15% using protocol 1 only, and 2.32% with both protocols. Details of the different protocols used in Benin are in the Appendix.

The healing rate in the CTE was 76.74%.

The objective of this study was to examine the profile of patients infected with SARS-CoV-2 and presenting at least one associated comorbidity in CTE in Benin. At the end of this study, we can retain that the combination of various techniques and tools used in data collection enabled us to achieve this objective.

The study was conducted as a retrospective approach. The methodology adopted was in line with the intended objective. However, a potential risk of information bias could remain in the patients’ records, as the data were collected from their medical files. The collection of these data was carried out by trained and supervised investigators on the use of the tools, ensuring a better understanding of the latter and helping to reduce bias.

The difficulties encountered during this study are related to the absence of some data in the patients’ records.

Two factors could account for the missing data, especially socio-demographic data in ETCs:

1) Excessive workload and time constraints: In the context of a pandemic such as COVID-19, treatment centers were often overwhelmed by the number of patients they had to care for. This meant that healthcare professionals had to juggle clinical care and record-keeping, which may have led to errors or omissions when records were filled in manually. Lack of time could have led staff to overlook details or postpone updating information, increasing the risk of incomplete data.

2) Fatigue and burnout: Working conditions during the pandemic were often marked by high stress and general exhaustion among healthcare staff. When files have to be filled in by hand, this demands continuous attention and concentration, which can be difficult to maintain for professionals already exhausted by workload and long hours.

1) Hospital prevalence

The hospital prevalence of COVID-19 cases associated with at least one comorbidity was 63%. Indeed, out of 819 hospitalized patients during the study period, 516 patients had at least one comorbidity from August 2020 to June 2021. We have no comparative study in Benin.

In Africa, there is a considerable variability, with prevalences ranging from 33.6% to 77%. In studies conducted by Calys-Tagoe and others in Ghana, Ahmed Kadi and others in Algeria, Donamou and others in Guinea Conakry, these prevalences were respectively 33.6%, 56%, and 77% [10] - [12] . This variability in results may be explained, on one hand, by the varying admission criteria at these care centers, and on the other hand, by factors related to lifestyle and age. In fact, the average age of patients was 41 years in the study by Calys-Tagoe and others [10] , 54 years with Ahmed Kadi and others [11] , 57.25 years with our study and finally 59 years with Donamou and others [12] . Age was proportional to the hospital prevalence of comorbidities among infected patients.

2) Age

The average age of patients admitted during the study period was 57.25 years. Compared to other studies, our results were similar to those of Donamou and others in Guinea Conakry (59 years) [12] . They were slightly higher than those of Ahmed and others in Algeria (54 years) [11] , the ones of Savadogo Mamoudou and others (53 years) [13] but lower than those of Louhaichi and others (61 years) in Tunisia [14] and Piva and others in Italy (64 years) [15] . Overall, older people were by far the most vulnerable to COVID-19. Results from an analysis conducted by EPI-PHARE in the general population showed that the risks of being hospitalized and dying due to this virus increase exponentially with age [16] .

3) Gender

The study population was dominated by male subjects (57.92%) with a sex ratio (M/F) of 1.38. According to studies in Africa, this male predominance varied between 54% and 79%. As a matter of fact, Calys-Tagoe and others in Ghana [10] , Savadogo Mamoudou and others in Burkina Faso [13] , Ahmed Kadi and others in Algeria [11] , Nkodia and others in the Republic of Congo [17] , Joseph Donamou and others in Guinea Conakry [12] , respectively reported a male predominance of 54%, 55.5%, 58.5%, 71.60% et 79%. In Canada according to a study by Mitra and others, this rate was 67.5% [18] . Men might therefore be more exposed to severe forms of the disease [18] . This male predominance may reflect differences in social and cultural activities between both genders. Men are generally the financial providers for families, which drives them to work. Being more mobile and generally in contact with a larger number of people than women, they may face a higher risk of contamination [19] .

4) Department of origin

In the CTE, the study population primarily came from the southern departments of the country. In fact, patients from these departments represented 62.78% of hospitalized cases. This rate is particularly significant considering that the department of origin was not reported for 23.17% of patients. The other departments, particularly those in the north and center, accounted for only 14.05% of patients.

The city of Cotonou was the most represented. Indeed, Cotonou, the economic capital of the country, is the city that hosts most of the administrative and political structures. Additionally, the presence of some key infrastructures (such as the international airport, Dantokpa market, and the Autonomous Port of Cotonou) facilitates human interaction, which is a significant catalyst for the infection. Data INSAE in 2017, put Cotonou as the most populated city of the country, though it is far from being the largest in terms of surface, which creates high population density [20] . The heavy influx of people from neighboring departments for economic and administrative activities also contributes to this density.

1) Comorbidities

The main comorbidities found were, in the order, arterial hypertension, diabetes, and obesity. Indeed, 68.34% of patients admitted to the CTE were at least hypertensive, 40.31% were at least diabetic, and 10.81% were at least obese. Donamou and others in Guinea Conakry reported similar results [12] . For Ahmed Kadi and others in Algeria, the two dominant comorbidities were arterial hypertension (45.94%) and diabetes (37.83%) [11] . For Kefti and others still in Algeria, the dominant comorbidity was arterial hypertension [21] . In Mitra and others’ study in Canada the most common comorbidities were hypertension (46.2%) and diabetes (30.8%) [18] . For Piva and others in Italy [15] , the most frequently found comorbidities were hypertension (45%) followed by diabetes (31%).

2) Functional symptoms

The functional symptoms were dominated by “Asthenia-Fever-Dyspnea-Cough”. These symptoms were respectively found in 57.56%, 51.55%, 45.93%, and 45.16% of patients. Salvadogo Mamoudou and others in Burkina Faso found exactly the same symptoms but with different proportions. In fact, fever, cough, dyspnea and asthenia were found in 86%, 69%, 60%, and 29% of cases, respectively [13] . Louhachi and others also found the quartet of fever (55%), cough (85%), dyspnea (85%) and asthenia (70%) [14] . For Kefti and others in Algeria, the combination of asthenia-Fever-Cough was found in 70% of cases [21] . For Donamou and others the most frequent clinical symptoms were dyspnea, asthenia and cough in 81%, 64% and 60% respectively [12] . For Ahmed Kadi and others, the most frequent clinical symptoms were dry cough (70.76%), fever (70.76%), asthenia (29.23%), dyspnea (26.15%) and diarrhea (26.15%) [11] . The functional symptoms of COVID-19 among patients admitted to the CTE were similar to other studies, notably with a preferential attack on the respiratory system (especially with cough and dyspnea).

1) Admission time

The average admission time was 6.17 days. It was less than 7 days for 308 patients, i.e. 60.75% of all patients. The maximum admission time was 60 days. This average was lower compared to studies conducted in Africa. Indeed, in the study by Sabrine Louhachi and others in Tunisia, the average admission time was 8 days [14] ; it was 10 days in the study by Kefti and others in Algeria [21] , 11 days in the study by Ahmed Kadi and others in Algeria [11] , and finally 12.43 days by Donamou and others in Guinea-Conakry [12] .

This relatively short period could be explained by:

- the systematic screening of all patients admitted to the emergency departments of the country’s public reference centers, facilitated by the government’s policy of setting up 13 new laboratories, enabling easier screening for COVID-19 in order to refer;

- the implementation of a call center service, not only for information on COVID-19 but also to report a suspected case;

- the implementation of mobile teams to conduct home assessments of symptomatic patients;

- the aggressive sensitization campaign launched by the government;

- the training of health workers on the pathology and the importance of knowing how to refer to CTE.

2) Discussion on patient therapeutic outcome

The therapeutic success rate in (CTE) during the study period was 76.74%. Our results were similar to those of Grasselli and others [22] (Lombardy), who found a resuscitation success rate of 74%, and higher than those of Bhatraju and others [23] and Xiaobo Yang and others [24] , who found 50% and 38.5%, respectively. This high therapeutic success rate observed in our study is practically the same as those found in other sub-Saharan African countries [25] . Indeed, several hypotheses can be raised to explain this low mortality rate, including the following:

- The precocious use of anticoagulants and corticosteroid in particular (high-dose dexamethasone) during the first weeks of the pandemic, even before the WHO declared that the use of dexamethasone reduced mortality in patients infected with SARS-CoV-2;

- The average age of our study population was lower compared to those found in American and European studies [26] [27] . In fact, an age above 60 years appeared to be strongly associated with mortality [28] .