Signs and symptoms of COVID-19
All the clinical presentations described in the national guidelines were found in our patients.
It is known that the clinical presentations of COVID-19 range from asymptomatic, paucisymptomatic to severe forms. In our sample, 38.4% of patients presented an asymptomatic form. A meta-analysis study reports a proportion of 31% of asymptomatic individuals based on seven studies of screened populations [17]. The same systematic review of 79 studies found that on average 20% (range 17-25%) of infected individuals remain asymptomatic for the duration of the infection [17]. It is evident that the real proportion of asymptomatic infected subjects remains difficult to know. The lack of information, the difficult access to screening centers, the fear of knowing that one is infected and of being confined, particularly at the beginning of the pandemic, were factors that limited screening.
- Symptomatic and moderate infection
The signs and symptoms of COVID-19 are varied. The predominant signs in our patients were cough (48.5%), difficulty breathing (24.6%), headache (19.7%), anosmia (14.9%) and ageusia (10.8%). This clinical polymorphism has been found in Africa and elsewhere. Jaspard & al. found signs of respiratory tract infection in 61% of patients and other signs including cough (46%), fatigue (41%), headache (37%), loss of smell (27%) and fever (16%) [17]. In China, Huang and al., reported that most people had fever (83-99%), cough (59-82%), fatigue (44-70%), anorexia (40-84%), shortness of breath (31-40%) and myalgia (11-35%) [18]. Other symptoms were found in all series in smaller proportions.
The proportion of severe forms was 15.5% in our series. Acute respiratory distress syndrome was the main complication of COVID-19 in our patients. In a series of Burkinabe and Guinean patients with COVID-19, the clinical worsening rate was 31%, higher than in our series [7]. According to Guan & al in China, acute respiratory distress syndrome occurred in 20% of patients after a median of 8 days [19]. The frequency of occurrence of complications depends on the population affected (with a higher susceptibility for the elderly and those with co-morbidities) and on the earlier or later recourse to care in specialist centers.
- Factors associated with severity and death
In patients with COVID-19, a number of risk factors have been identified on the African continent and elsewhere as having a potential impact on progression to severe forms, including old age, male gender and pre-existing comorbidities [20, 21].
In our series, a large majority (81.6%) of the patients who died were aged 60 years and over, compared to 21.4% of deaths in patients under 60 years of age (p<0,001). Also, the average age of the deceased patients (68.2 years ± 11.2) is higher than that of the cured patients (43.3 years ± 17.7) (p<0,001). Our results are consistent with those described in the sub-region and elsewhere in the world. Indeed, according to Jaspard & al., mortality was 3 times higher among 60-year-olds in Burkina Faso and Guinea [7]. Muller & al., reported that advanced age predisposes to the progression of COVID-19 to a severe form and high mortality [22]. Indeed, with a reduced efficiency of the immune system, the elderly tends to have a higher risk of developing infectious diseases, including COVID-19 [23]. The most plausible hypothesis is that the chronic pro-inflammatory state associated with ageing of the immune system with persistent low-level innate immune activation may increase tissue damage caused by infections in the elderly [24]. In addition, higher levels of pro-inflammatory cytokines with age may contribute to the development of this disease [25].
Although the number of deaths observed is higher in males than in females in our series, we did not observe any statistical difference in the gender proportions of the deceased and the no death (p=0,99). On the other hand, some authors have reported that men have a higher risk of death from COVID-19 than women [20, 21]. Several factors have been put forward to explain this greater male vulnerability, notably differences in anatomy, lifestyle and behavior, co-morbidities, socio-economic conditions and even immunity [23, 26, 27].
Several studies have shown that the presence of co-morbidities, including no-comunicable diseases such as cardiovascular disease [6, 7, 28, 29], high blood pressure [7, 30, 31], diabetes [28, 30], constructive obstructive pulmonary disease (COPD) [30-31], malignancy [31], cerebrovascular disease [30] and chronic kidney disease [32], are factors in the severity and death of patients with COVID-19. In our sample, high blood pressure and diabetes were the comorbidities associated with death; more than half of the deceased patients had high blood pressure (p<0.001) and slightly less than half had diabetes (p <0,001). In Africa, Jaspard & al., reported that mortality was twice as high in people with high blood pressure [7]. These clinical spectra are therefore in line with the literature and underline the severity of the disease in at-risk groups, in Africa as elsewhere. This evidence has led to the need for appropriate management to try to reduce the high mortality rate in these groups.
In addition to the clinical symptoms, SARS-CoV-2 can cause numerous biological abnormalities. The most frequently reported coagulation/fibrinolytic abnormality in COVID-19 is increased D-dimer and its relationship to prognosis has been discussed [33]. The mean D-dimer level in our dead patients was much higher than in the cured cases with a significant statistical difference (p< 0,001). The mean D-dimer in dead patients of 3.3±3.2 is higher than in surviving patients of 0.81±1.9. Other authors have suggested that the prognosis of COVID 19 can be estimated by D-dimer levels on admission [33-35]. The limitation of this measurement in our study is that it was performed on admission, in general, the test was not repeated in most cases. However, according to Asukura and al. an accurate prognostic assessment cannot be obtained with admission data alone, as the coagulation/fibrinolytic status sometimes fluctuates within a short period of time [33]. Thus, regular reviews in recognition of the importance of the review are desirable. Although these benefits are known, repeated testing has a cost and increases the workload, which was already high during the waves. Patients were tested for COVID-19 when signs of severity were already present. Fear of confinement, lack of information about COVID-19, and traditional treatment and self-medication habits were key factors in the late management of patients. Acute respiratory distress syndrome (polypnea (p<0.001; [HR=1.14 (1.07-1.22)], breathing difficulty (p=0.037, [HR=3.06 (1.03 - 9.13)] and low O2 saturation) were the main risk factors for death in our COVID-19 patients. Indeed, the average respiratory rate in our dead patients was 25.2±7.8 compared to 17.6±4.8 in the recovered patients (p<0,001). Similarly, the mean O2 saturation was low, 84.9%±13.36 in death patients compared to 95.5%±6.4 in no death patients. Of the 49 deaths, 44 (89.8%) had an acute respiratory distress syndrome, all were ventilated. Indeed, some authors report that the mortality rate in patients ventilated with COVID-19 acute respiratory distress syndrome is one of the most discouraging published outcomes. Mortality among critically ill ventilated patients ranges from 67-97% in ventilated Chinese patients [32, 36] and has been estimated at 88% in New York [37].