In our series, we found that the mean age of our patients was 57 years, with a slight predominance of males. Our patients were hypertensive in 61.8% of cases, diabetic in 44.8% and were known to have underlying heart disease in 19.4% of cases.
Eighty-five percent of the patients had chronic kidney disease of whom 63.8% were at stage 5 of CKD.
In a series of 72,314 patients infected with SARS cov2, Zunyou W and al reported that 87% of the population was aged between 30–79 years (4).
In another larger series published by the US Centers for Disease Control and Prevention including 1,320,488 patients, the median age was 48 and the number of incident cases was similar between male and female patients (5).
According to the same publication, the most frequent co morbidities were cardiovascular disease (32.2%), diabetes (30.2%), chronic lung disease (17.5%) and chronic kidney disease (7.6%) (5).
Another result concerning co morbidities during SARS COV2 infection published by Geehan S and al is summarized as follows: hypertension (63.7%), obesity (57.6%), chronic kidney disease (39.3%), diabetes (38.4%), ischemic heart disease (12.7%), congestive heart failure (10.6%) and end-stage renal disease (5.6%) (2).
In the study by Mythri S and al, the authors studied the characteristics of 90 patients with chronic kidney disease hospitalized following infection with SARS cov 2. These patients were aged between 51 and 60 years old in 42% of cases, and had mainly hypertension, diabetes and cardiovascular disease (3).
A second Italian study published by Dino G and al, evaluating the characteristics of 193 non-dialyzed chronic kidney patients from January 2020 to July 2020 reported the following findings: patients had a mean age of 80.8 years (significantly older than our population) and were hospitalized following infection in 95.4% of cases. There was a clear predominance in man (63.7% vs 57% for our population), the main co morbidities reported in this publication were: obesity (35.5%), diabetes (35.7%), cardiac heart disease (39.9%), chronic obstructive pulmonary disease (13.5%), tumours (10.9%), the mean GFR for this population was 32.5 ± 12.1 ml/min and therefore significantly higher than the mean GFR of our population. The majority of patients had stage 3 and 4 renal disease unlike our population where stage 5 was predominant. For them, vascular nephropathy was the dominant underlying nephropathy (77.7%), diabetic nephropathy accounted for only 8.8%, in contrast to the results of our study, in which diabetic nephropathy was the most common etiology(29%)(6).
In our study, the clinical signs frequently reported by our patients were asthenia, fever, cough, dyspnea and arthralgy/myalgia.
There was evidence of contact with a confirmed COVID 19 case in 45% of cases.
The median time to hospitalization, PCR performance and length of hospital stay were respectively 5; 5 and 7 days.
In the study reported by the US Centers for Disease Control, the authors reported the frequency of clinical symptoms in 616,541 patients as follows: 4% were asymptomatic,70% had at least one symptom from: fever, dyspnea or cough. Myalgia and headache accounted for 36% and 34% respectively in the same series (5).
We found that the frequency of anosmia-agueusia - a very specific sign of SARS infection Cov2- is 1.8%, it was slightly higher(8.3%),in this American publication (5)
Geehan S and al in a study of 463 COVID 19 patients in the United States found a frequency of contact with a confirmed COVID 19 case (26.8%) lower than our result (2).
According to these same authors, the most frequent clinical signs of this infection are: cough (74.9%), fever (68%), dyspnea (60.9%) and myalgia (42%) (2).
The ERACODA study, which included renal transplanted patients and dialyzed patients, reported high frequencies of the most frequent clinical signs reported in the literature, which are fever (75%: renal transplanted patients, 54% : dialyzed patients), cough (67% transplanted patients, 45% dialyzed patients), dyspnea (46% transplanted patients,32%: dialyzed patients), myalgia and arthralgia (28%: transplanted,20% :dialyzed patients), diarrhea (31%: transplanted patients,11%: dialyzed patients). The mean duration between onset of symptoms and hospitalization was 7 days for transplanted patients and 3 days for dialysis patients (7).
In another study, the period was 9 days (8).
The main laboratory abnormalities noted in our patients were: elevated LDH, lymphopenia, metabolic acidosis, hypo-eosinophilia,dysnatremia, dyskalaemia and low Prothrombin rate.
In addition, there was a marked rise in CRP, a very high mean creatinine level and a median GFR that was consequently very impaired.
In the ERACODA study, the most frequent laboratory abnormalities were lymphopenia (median of 800/ul and 900/ul for transplanted and dialyzed patients respectively), elevated CRP (median 52 and 21 mg/l respectively for transplanted patients and dialyzed patients).
The median GFR (CKD-Epi method) for transplanted patients was 37 ml/min (7)
Yichun CH and al analyzed the results of 701 patients admitted for COVID 19, the prevalence of chronic kidney disease among them was 14.4%.The main biological abnormalities noted were: a mean lymphocyte count of of 800/ul, low Prothrombin rate, elevation of D-dimer, procalcitonin, LDH and CRP. The mean values for kalemia, creatininemia and blood urea nitrogen were 4.5 ± 0.7 mmol/l, 132 ± 39 umol/l,11 ± 7 mmol/l respectively (8)
Radiologic involvement on chest CT in our patients was estimated to be moderate in 44%, minor in 34% and severe in 22% of cases.
Camila C and al performed 453 chest scans on COVID 19 patients at the request of the clinicians caring for them to assess the severity of the CT involvement and the most common lesions.
The ground-glass was the most frequent lesion (92.5%), pulmonary involvement was estimated as follow: severe (13%), moderate (32%), mild (29.8%), minimal (21%) and absent in 4.2% of cases (9).
In a review of the literature, the authors found cumulative incidences of lung involvement on chest CT in COVID patients to be: mild: 7.6%, moderate: 61.83%, severe: 24.48% and critical: 6.11% of cases.
These radiological findings correlate perfectly with the severity of clinical involvement according to the authors of this review (10)
The death rate for our patients was 15.8%. Acute renal failure occurred in 16.4% and worsened chronic renal failure in 32.7%. The rate of pulmonary bacterial super infection was estimated at 23.6%. Regarding the severity of COVID 19 disease, our population was divided into four groups: asymptomatic (12.7%), pauci-symptomatic (30.3%), moderate (11.5%) and severe (45.5%.).
In a large Chinese study including 72 314 patients infected with SARS COV2 the overall mortality rate was 2.3%, that increases with age so patients aged 70–79 and over 80 years old died respectively in 8 and 14.8% of cases
The death rate for Critical patients was 49%.mostly patients had mild disease (81%), severe and moderate disease and critical forms accounted respectively for 14% and 5%.( 4)
In comparison to this Chinese study, our population including higher rate of CKD patients had more severe forms of the disease and higher mortality.
In another American study on a large sample of the general population, the death rate was 5% (5).
Mythri S and al conducted a study on 90 chronic kidney patients in India who were infected with SARS COV2 and required hospitalization, the mortality was significantly higher than our study, i.e. 34.4% (3)
Dino G and al reported an even more fatal outcome of chronic kidney patients they studied and who had a very advanced average age. The rate of mortality was 44.56% (6)
The rate of AKI was estimated at 11.9% in a Chinese study and that of death is by 33.7% (8)
In univariate analysis, we were able to show that advanced age, diabetes, hypertension, underlying heart disease and subpopulation who do not receive any renal replacement therapy are the most associated with severe forms
In multivariate study, advanced age increases the risk of severe illness.
With regard to chronic kidney disease, several studies have shown that it is an aggravating factor in COVID 19 disease, as will be illustrated in the rest of this paragraph. In our study we were unable to show this result.
The authors of an Indian study of 90 chronic renal patients hospitalized for COVID disease concluded that advanced age (mean 53.9 years old) diabetes and cardiovascular disease were significantly associated with death (3)
Raul L and al evaluated the characteristics of 870 patients admitted to the hospital because of COVID 19, 50% of whom had impaired renal function on admission.
Their results are similar to our findings concerning the adverse impact of advanced age and chronic heart disease on the severity of the disease and the neutrality of the effect of CKD on illness severity.
On the other hand, they found that obesity significantly affected the severity of infection (11)
In a study of 463 patients in the United States, the authors were able to show an association between advanced age, male gender, diabetes, hypertension, chronic kidney disease and a history of cancer and the hospitalization in the intensive care unit, when they finalized the multivariate analysis of COVID 19 patients, they concluded that the advanced age of their patients, morbid obesity and chronic kidney disease were significantly and independently associated with admission to intensive care units (2).
Similarly, the authors of the STOP-COVID study concluded that for seriously ill patients admitted to intensive care, the number of co-morbidities was higher for patients on dialysis or with CKD not yet dialyzed (12)
Chronic dialyzed patients had a greater need for vasopressor drugs than chronic kidney disease patients not yet dialyzed (12).
Seok Hui K and al analyzed data from 7341 patients divided into three groups: CKD, dialyzed patients and a control group and found that major events such as AKI, acute heart failure, the need for vasopressor drugs and mortality were significantly higher in the dialyzed arm (13)
Ankur D and al focused on SARS COV2 infection only in dialyzed patients and concluded that this particular population had atypical clinical presentations, higher rate of hospitalization, and higher mortality (14)
Our results highlighted that patients who presented with fever, dry cough, asthenia, as well as those with the longest delay between the onset of symptoms to PCR and hospitalization had significantly worse outcome than the rest of the patients.
The Contact with a confirmed COVID case was associated with milder forms of the disease.
In multivariate analysis, dry cough was significantly associated with severe forms and diarrhea tended to be associated with milder forms of the disease.
According to Geehan S and al on an analysis of data from 463 patients: headache and fever were associated with intensive care unit admission for severe COVID disease (2)
According to another Indian study of chronic kidney disease patients infected by SARS Cov2; no association was found between clinical signs and severity of prognosis (3).
Maureen B and al, through the STOP-COVID study, concluded that for severe COVID patients admitted to the intensive care unit, patients on dialysis or known to have chronic kidney disease not yet dialyzed had more atypical manifestations of the disease and, above all, a much greater deterioration in mental status than other patients.
the time taken to transfer these patients to intensive care once they had been admitted to hospital were 4 days for dialyzed patients and 7 days for other patients. (12)
Chung and al reported an incidence (per 1000 patients per week) of dyspnea in patients with CKD and COVID 19 of 80, 95% CI (66 − 9), and an incidence of hospital admission of 93.95% CI (82–104) (15).
In our study, the most severe patients had significantly higher levels of CRP and LDH.
Mythri S and al reported the main biological parameters associated with poor outcomes of chronic kidney disease patients admitted to hospital following a COVID 19. The group of patients cured of infection had a significantly lower neutrophil/lymphocyte ratio, lower D-dimer levels, higher albumin levels, less disturbed liver function tests, lower: CRP, lactate and LDH levels and less acidemia compared with the group of patients who died (3).
The results of the STOP COVID study carried out on seriously ill patients in intensive care units presumed that for chronic renal patients whether dialyzed or not: the white blood cells and platelets counts as well as fibrinogen level were low, and levels of ferritinemia, CRP, troponin and IL6 were very high (12).
Similarly, Savas O and al published the main biological disturbances they found to be associated with severe forms of COVID in a population comprising dialyzed patients, chronic kidney patients and transplant patients, they compared with a control group (with no nephrologic concerns) and the results were as following: severe arm had more leucopenia, lymphopenia, thrombocytopenia, anemia, elevated LDH, higher mean ferritinemia, CRP and creatinemia and lower mean serum albumin levels (16).
These biological results have been validated by other teams (17) (18) (19).
In our study, patients with more severe disease had more frequent bacterial pulmonary
super infection and acute renal failure. Even in the multivariate analysis, pulmonary bacterial super infection was independently associated with moderate and severe forms.
The results of a Chinese study reported other types of complications that are associated with severe forms of the disease and patient death. These were acute renal failure, proteinuria and haematuria, which increased the risk of mortality. For example if the proteinuria is 3 crosses on multistix urinalysis, the hazard ratio for death is 12.2, 95% CI: 6.32–23.53, P < 0.001 (8)
Chung and al reported in patients with CKD and COVID 19 an incidence of death (per 1000 patients per week), resuscitation admission, acute renal failure and sepsis respectively of 32, 95% CI (30–35), 27.95% CI (24–30), 73 95% CI (60–87), 3 95% CI (0–8) (15).
The ratio of incidence rates of death in patients with COVID 19 and without COVID 19 were 10.26; 95% CI, 6.78–15.53 (15).
Dawei W and al compared complications in severe and non-severe COVID patients and found significantly stronger associations with severe forms of: acute renal failure (8.3% severe vs. 2% non-severe, p < 0.001), acute cardiac failure (22.2% severe vs. 2% non-severe, p < 0.001), shock (30.6% severe vs 1% non-severe, p < 0.001), ARDS (61.1% severe vs 4.9% non-severe < 0.001) (17)
Chaolin H and al, reported a statistically significant increase in the occurrence of some major events in patients admitted to the intensive care unit following SARS COV2 infection compared with a group of patients admitted to a medical department which were: ARDS (85% vs. 4%), acute heart failure (31% vs 12%), acute renal failure (23%, vs 7%), secondary infections ( 31% vs, 10%), shock (23%, vs. 7%), and dialysis (23%, vs. 7%).all differences were significant (18)
The association of organ failure, in particular kidney failure, with the poorest prognosis of COVID has been highlighted by several publications (19) (20) (21)(22)