RJHS 11(4).cdr


Kidney dysfunction and mortality risk in hospitalized Covid-19 
patients: A large Covid-19 centre experience 

1 1 2 2
Mamven H.M. , Kwaghe G.V. , Habib G.Z. , Galadima S.U.

Abstract
Objective: Kidney dysfunction is common in patients infected with the coronavirus (COVID-19). The 
study's objective was to determine the relationship between glomerular filtration rate and mortality in 
COVID-19 patients.

Methods: This is a retrospective cohort study of patients admitted into the COVID-19 isolation center 
from March 2020 through December 2021. The serum creatinine at admission was used to estimate the 
glomerular filtration rate (eGFR) using the CKD equation method. The patients were categorized into 2 
groups based on the eGFR (≥ or < 60ml/minute). The outcome was in-hospital mortality. Kaplan Meier 
survival plots and cox proportional modelling were employed in the data analysis.

Results: A total of 623 patients were analysed. The mean age was 53.4±15.3 years, and 58.6% were male. 
An eGFR of < 60 ml/min was observed in 196 (31%) patients. A significantly higher number of deaths 
occurred among patients with eGFR <60ml/min (32% vs 10.5% (P<0.001). After adjusting for age, sex, 
disease severity, haemoglobin, ICU admission, and dialysis, the patients with reduced eGFR of 

 
(<60ml/min) were twice more likely to die than patients with eGFR ≥ 60mls/min (AHR 1.95, 95% CI 1.26-
3.04, P = 0.003). 

Conclusion: eGFR of < 60mls/min is associated with an increased risk of mortality in COVID-19 
patients. This stresses the need for better recognition of renal dysfunction as a high-risk for mortality in 
COVID-19 infections.

Keywords- COVID-19, eGFR, Mortality

*Corresponding author
Mamven H.M. 

Email: manmakm@yahoo.com

1
Department of Medicine, College of Health Sciences, University of Abuja, Nigeria

2
Department of Medicine, University of Abuja Teaching Hospital, Gwagwalada Abuja Nigeria

                                        Received: May 22, 2023 Accepted: July 2, 2023    

ORCID-NO: https://orcid.org/0000-0003-3229-6689

Original Article Research Journal of Health Sciences

Res. J. Health Sci. Vol 11(4)                                                                                     296

Research Journal of Health Sciences subscribed to terms and conditions of Open Access publication. Articles are distributed under the terms of 
Creative Commons Licence (CC BY-NC-ND 4.0). (http://creativecommons.org/licences/by-nc-nd/4.0). 

http://dx.doi.org/10.4314/rejhs.v11i4.2



Dysfonctionnement rénal et risque de mortalité chez les patients 
hospitalisés Covid-19: une grande expérience de centre COVID-19

1 1 2 2
Mamven H.M. , Kwaghe G.V. , Habib G.Z. , Galadima S.U.

Résumé 
Objectif de l'étude: Le dysfonctionnement rénal est fréquent chez les patients infectés par le coronavirus 
(COVID-19). L'objectif de l'étude était de déterminer la relation entre le taux de filtration glomérulaire et 
la mortalité chez les patients COVID-19.

Méthode de l'étude : Il s'agit d'une étude de cohorte rétrospective de patients admis dans le centre 
d'isolement COVID-19 de mars 2020 à décembre 2021. La créatinine sérique à l'admission a été utilisée 
pour estimer le taux de filtration glomérulaire (eGFR) à l'aide de la méthode CKD EpI. Les patients ont été 
classés en 2 groupes en fonction du DFGe ( ≥ ou < 60 ml/minute). Le critère de jugement était la mortalité 
hospitalière. Des diagrammes de survie de Kaplan Meier et une modélisation proportionnelle de Cox ont 
été utilisés dans l'analyse des données.

Résultat de l'étude: Au total, 623 patients ont été analysés. L'âge moyen était de 53,4 ± 15,3 ans et 58,6 % 
étaient des hommes. Un DFGe < 60 ml/min a été observé chez 196 (31 %) patients. Un nombre 
significativement plus élevé de décès est survenu chez les patients avec un DFGe<60 ml/min (32 % contre 
10,5 % (P< 0,00 1). Après ajustement en fonction de l'âge, du sexe , de la gravité de la maladie , de 
l'hémoglobine, de l'admission en USI et de la dialyse, les patients avec un DFGe réduit de ( <60 ml/min ) 
étaient deux fois plus susceptibles de mourir que les patients avec un DFGe ≥ 60 ml/min ( A HR 1,9 5 , IC à 
95 % 1,2 6- 3,0 4 , P = 0,00 3 ).

Conclusion : un DFGe < 60 ml/min est associé à un risque accru de mortalité chez les patients COVID-19. 
Cela souligne la nécessité d'une meilleure reconnaissance de la dysfonction rénale en tant que risque élevé 
de mortalité dans le COVID-19 infections.

Titre du fonctionnement courant : Taux de filtration glomérulaire estimé et risque de mortalité.

Mots-clés - COVID-19, eGFR, mortalité

*Corresponding author
Mamven, H.M.

Email: manmakm@yahoo.com

1
Department of Medicine, College of Health Sciences, University of Abuja, Nigeria

2
Department of Medicine, University of Abuja Teaching Hospital, Gwagwalada Abuja Nigeria

            Received: May 22, 2023 Accepted: July 2, 2023

ORCID-NO: https://orcid.org/0000-0003-3229-6689

Article Original Research Journal of Health Sciences

Res. J. Health Sci. Vol 11(4)                                                                                     297

Research Journal of Health Sciences subscribed to terms and conditions of Open Access publication. Articles are distributed under the terms of 
Creative Commons Licence (CC BY-NC-ND 4.0). (http://creativecommons.org/licences/by-nc-nd/4.0). 

http://dx.doi.org/10.4314/rejhs.v11i4.2



INTRODUCTION
Coronavirus disease (COVID-19) is a 

novel disease caused by the severe acute 
respiratory syndrome coronavirus 2 (SARS-
CoV-2) that is responsible for the global 
pandemic recently (1). Though respiratory 
involvement is the major presentation, other 
organ involvement is common, especially in 
severe cases. (2) The kidneys are one of the most 
c o m m o n l y  a f f e c t e d  o r g a n s .  K i d n e y  
abnormalities have been reported globally by 
several authors (3-6). The spectrum of renal 
involvement described in COVID-19, includes 
urinary abnormalities and changes in kidney 
function (reflected by decreased glomerular 
filtration rate (GFR) which might be present in up 
to 75%-80% of cases.(6) Acute kidney injury 
(AKI) at one end of the spectrum is a common 
complication and may be due to several causes 
s u c h  a s  s e p s i s ,  h y p o t e n s i o n ,  o r  
glomerulonephritis (7-9). Proteinuria and 
haematuria with or without the loss of kidney 
function are also common abnormalities 
encountered in these patients (7-10).

Several mechanisms for kidney damage 
have been proposed such as acute tubular injury 
from systemic hemodynamic changes, tissue 
inflammation, and local immune cell infiltration 
with endothelial injury and microvascular 
thrombi and possibly viral invasion in the 
kidneys. An impaired type I interferon response 
has also been reported in patients with severe 
COVID-19 (11). Kidney dysfunction in COVID-
19 patients is associated with increased mortality 
(5,10,12). Other Significant independent 
predictors of mortality reported are older age, the 
presence of comorbidities such as diabetes 
mellitus, hypertension, and proteinuria (12-14). 

During the early part of the COVID-19 
pandemic, not much attention was paid to testing 
for kidney abnormalities routinely during 
hospitalization in many centres in Nigeria, unless 
there were obvious signs of kidney involvement, 
which might have been noticed too late. Our 
centre is a major referral centre that is well 
equipped to manage systemic complications such 
as kidney failure and has good laboratory support 
to run samples with a quick turnaround time of 
results. This significantly contributed to our 
success in managing COVID-19 infection. Few 
large studies have been conducted on kidney 
function and mortality outcomes in COVID-19 
patients in Nigeria. The purpose of our study was 
to investigate the impact of eGFR (kidney 
function) on in-hospital mortality in hospitalized 
patients with COVID-19. We hypothesize that an 
estimated glomerular filtration rate (eGFR) of 

2  
less than 60mls/min/1.73m  at admission is 
significantly associated with mortality among 
patients with COVID-19. The finding of this 
study will increase clinicians' awareness of 
kidney dysfunction in our hospitalized patients 
with COVID-19.

MATERIALS AND METHODS 
Setting and design 

The study was conducted at a major 
referral hospital in the North Central region of the 
Country. The hospital is a treatment centre for 
moderate to severe cases of COVID-19 in the 
Federal Capital Territory (FCT) in Nigeria. 

The design was a retrospective cohort 
study involving all adult patients aged?18 years 
and above with at least one respiratory sample 
positive for SARS-CoV-2 by polymerase chain 
reaction (PCR), admitted to the isolation and 

st
treatment centre between the 21  of March 2020 
and December 2021. We excluded patients with 
no measurements of creatinine at admission.

Sample size determination
For obtaining the minimum sample size, 

assuming that 18.4% of COVID-19 patients with 
eGFR > 60mls/min will die during the study,(14) 
and a prevalence of reduced eGFR in COVID-19 
patients of 30% (14), with a power of 90% and 
alpha of 0.05, we would like our study to have 
adequate power to detect a relative risk of 2.0. A 
minimum sample size of 294 with N1=89 and 
N2=205 was required. 

Data sources
The data were extracted from the patient 

medical records by a trained research assistant. 

Variables and definitions
The primary exposure of interest was the 

eGFR. Using the creatinine obtained at 
admission, age and sex it was calculated using the 
CKD-EPI creatinine formula (15). Other 
exposures were age, sex, clinical features on 
admission such as oxygen saturation (SP02%), 
blood pressure, severity of COVID-19 disease, 
Elixhauser comorbidity index score (CIS), 
t r e a t m e n t  r e c e i v e d  s u c h  a s  o x y g e n  
supplementation, renal replacement therapy use, 
use of medications and intensive care unit 
requirement. Laboratory data was full blood 
count, serum urea, creatinine, potassium, 
sodium, and bicarbonate obtained during 
admission.

For the purpose of this study, patients 
were categorised into two groups according to 

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Kidney function abnormality and risk of mortality                                                                Mamven et al.



their eGFR. Group one was made up of patients 
with eGFR ≥?60ml/min/1.73  while group two 
w a s  m a d e  u p  o f  t h o s e  w i t h  e G F R  

2
<60ml/min/1.73 m  which (was termed low 
eGFR).(15)

The severity of respiratory COVID-19, 
cases was obtained from the patient's records and 
were categorized as mild, moderate, and severe. 
The comorbidity index score (CIS) was 
according to Elixhauser comorbidities and van 
wolverine scoring .(16,17) The neutrophil-
lymphocyte ratio (NLR) at hospital admission 
was calculated as the ratio of neutrophils to 
lymphocytes and both were obtained from the 
blood sample collected. 

The outcome was in-hospital mortality 
and the time from admission to death. In-hospital 
mortality was all-cause deaths within 30 days of 
being admitted to the hospital. The time to event 
was the time from hospital admission to events 
w h i c h  w a s  a l l - c a u s e  d e a t h .  C e n s o r e d  
observations were those who had not yet had the 
event. Patients were censored on the day of 
discharge or 30 days from the day of admission if 

st
still alive and on 31  December 2021, the final 
date of follow-up for this study.

Statistical analysis
The normality of variables was assessed 

using visual inspection of histograms and 
confirmed by the Shapiro–Wilk test. Any variable 
with more than 10% missing was not used.  

Patient characteristics were described for 
the overall cohort according to the two groups of 
eGFR. Categorical variables were summarized as 
proportions and percentages and continuous 
variables were expressed as the mean and 
standard deviation (SD) or median with 
interquartile range (IQR) for skewed measures. 
We compared characteristics between the eGFR 
groups using chi-square or Fisher exact tests for 
categorical variables.  Two samples independent 
t-test or Wilcoxon rank-sum (Mann-Whitney U) 
test for skewed data was used to compare 
continuous variables between the two groups.

We explored the relationship between 
e G F R  a n d  3 0 - d a y  m o r t a l i t y  u s i n g  a  
Kaplan–Meier survival curve with the log-rank 
test. Univariable and multivariable Cox 
proportional hazards regression models were 
estimated, to further explore the relationship 
between eGFR and in-hospital death while 
adjusting for any confounders. Results were 
reported as hazard ratios (HR) with a 95% 
confidence interval. The proportional hazard 
assumption was tested using graphical means. 

Given the multiplicity of variables, We 
p e r f o r m e d  v a r i a b l e  s e l e c t i o n  f o r  t h e  
multivariable model building and used a stepwise 
selection of variables to select variables for the 
model.  Other variables of known clinical 
relevance were added. Potential confounding 
variables were age, sex, comorbidities index, 
disease severity, haemoglobin concentration, and 
ICU admission. All tests were two-sided and the 
statistical significance was P <0.05 for all 
analyses. 

Data were collected and managed using 
Excel and statistical analyses were performed 
using STATA software (16.1 StataCorp LLC, 
College Station, TX). 

Ethical statement 
The study was approved by the Health 

Research Ethics Committee of the institution 
w i t h  t h e  n u m b e r :  
UATH/HREC/PR/2022/003/006 on 21/03/2022 
and was conducted in accordance with the 
National HREC code and with the Helsinki 
Declaration of 1975, as revised in 2000. A waiver 
of informed consent for patients was obtained as 
this was a review of the data collected. Strict 
confidentiality of data was maintained. 

RESULTS
Out of the 750 patients hospitalised with 

COVID-19 during the period, 623 formed the 
primary sample for analysis. 196 (31%) had 
eGFR of < 60ml/min. 

Characteristics of the primary sample are 
demonstrated in Table 1. A significant proportion 
of the lower eGFR group of < 60 ml/min was 
older and had a higher proportion of patients with 
diabetes, hypertension, anaemia, severe COVID-
19, sepsis, and higher median CIS than those with 
eGFR ≥ 60 ml/min. Patients with eGFR < 60 
ml/min also had lower levels of median oxygen 
saturation, lower mean haemoglobin, and lower 
bicarbonate levels. They also had higher mean 
WBC, and NLR. The treatment most frequently 
used was antibiotics (64.4%), dexamethasone 
(60.4%), and clexane (56.8%). The group with 
the lower eGFR was less frequently treated with 
antivirals (lopinavir/ritonavir) (6.6% vs 30.4%) 
and were more frequently treated with antibiotics 
(85% vs 54.9%), dexamethasone (79.5% vs 52%) 
and oxygen supplementation (55.6% vs 32.0%). 
A higher proportion of deaths occurred among 
patients with lower eGFR than in the higher 
eGFR group. (32 % vs 10.5%; P<0.001) (Table 1)

Figure 1 displays the Kaplan-Meier 
survival curves in the two eGFR groups. 

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Kidney function abnormality and risk of mortality                                                                Mamven et al.



Mortality was significantly higher in patients 
2

with eGFR < 60mls/min/1.73m  (global log-rank 
test P < 0.001). There were no violations of the 
C o x  p r o p o r t i o n a l  h a z a r d s  a s s u m p t i o n s  
graphically. 

Tables 2a and b demonstrate the 
distribution according to survival status in the 
patients. A significantly higher proportion of 
patients with COVID-19 who died were older. 
Those who died had more severe COVID-19 than 
mild disease, and higher median CIS than 
survivors. Table 2b shows the treatment of the 
patients. A significantly higher proportion of 
patients who were admitted into ICU died 
compared to those who were not. More of those 
treated with antibiotics (25.3 vs 3.7%), clexane 
(24 vs 9%) and with corticosteroids (25vs 7%) 
died compared to those who were not. A 
significantly higher proportion of patients who 
had dialysis did not survive compared to those 
who did not have (Table 2). 

The Cox proportional analysis is 
displayed in Table 3, the unadjusted hazard ratio 
for eGFR 
<60 ml/min on mortality was 3.3, while the 
adjusted hazard was 1.95 (95% CI, 1.26-3.04). 
The confounders, were age, sex, disease severity, 
haemoglobin, ICU admission, and dialysis. 
(Table 3). The Cox proportional hazards 
assumption after adjusting for confounders was 
met on graphical analysis.

DISCUSSION 
In this study, we looked at the kidney 

function using the eGFR observed during 
admission and associated it with Mortality in 
patients afflicted with COVID-19. We observed 
that 31% of our patients had an eGFR of < 60 

2
mL/min/1.73 m . This is consistent with several 
other authors globally that kidney dysfunction 

2
(low eGFR of <60 mL/min/1.73m ) is not 
uncommon in confirmed cases of COVID-19 
infection.(14, 18, 19) Uribarri, Mirijello and Cei 
reported similar values of about 30%,27.3% and 
30% respectively in their patients.(14, 18, 19) On 
the other hand Cheng reported lower prevalences 
of elevated serum creatinine, blood urea nitrogen 

2
and eGFR under 60 ml/min/1.73m  of 14.4, 13.1 
and 13.1%, respectively .(10) In SSA and 
specifically reporting on AKI as the dysfunction, 
Ibrahim et al. reported AKI occurring in 14.6% of 
their patients while Dolaamas reported higher in 
32.6% .(20, 21)  A report from a hospital-based 
registry in Ghana showed that 10% of patients 
admitted with COVID-19 had underlying CKD 
with AKI in nearly half of the cases.(22) This 

wide variation in prevalence of the kidney 
abnormalities is most likely due to heterogeneity 
in cohorts studied, from variations in definitions 
and components of kidney dysfunction to 
methods employed in diagnosis and reporting. 
While the studies reported on several renal 
abnormalities, our study reported low eGFR as 
the sole dysfunction.

Kidney disease in COVID-19 is 
associated with an enhanced risk of deterioration 
and mortality. In this study, we observed 32% 
mortality in our patients with kidney dysfunction 
and 10.5% in those with eGFR >60mls/min. The 
hazard of mortality in our patients wth 
dysfunction was 1.9, 95% CI: 1.26-3.04, p = 
0.003 after adjusting for age, sex, disease 
severity, haemoglobin levels, ICU admission, 
and dialysis as confounders. Similarly, several 
other investigators worldwide reported high risk 
of mortality in their COVID-19 cohorts with 
renal dysfunction. In Africa, Dolaama reported 
death in 55.8% of their patients with kidney 
dysfunction and the factors associated with death 
were, KDIGO stage (p = 0.049), and invasive 
ventilation (p < 0.001). (21) In Ghana, In-hospital 
mortality of 43.5% was reported among those 
with CKD in an unpublished hospital-based 
report of COVID-19 patients admitted at the 
Komfo Anokye Teaching Hospital as of February 
2021.(22) 

In Italy, Cei, et al., showed that an eGFR 
value of <60 mL/min/1.73 m2 (OR 2.6,95% 
CI:1.7-4.8, p = 0.003); as well as age >?73 years 
(OR 4.3, 95% CI: 2–9, p?<?0.001), lymphocyte 
count below 460?U/L (OR 3, 95% CI 1.4–6.4, 
p?=?0.004) and platelet count below 177,000 (OR 
2.2, 95% CI 1.2–4.2, p?=?0.017) were 
significantly associated with in-hospital 
mortality (19), also in Italy Mirijello 
demonstrated a risk of 1.64 for low eGFR (AHR 
1.64, 95% CI 1.02–2.63, P = 0.040).(18) In china 
Cheng et al., reported 16% of their patients died 
in-hospital and had a significantly higher risk for 
in-hospital death with an elevated creatinine 
(AHR:2.10, 95% CI: 1.36-3.26) (10). Pei et al. 
reported mortality in 11.2% of their patients with 
kidney involvement compared with (1.2%) of 
patients, without  (7). Chan et al., reported higher 
mortality of 50% among their patients with AKI 
versus 8% among those without AKI (AOR, 9.2; 
95%CI: 7.5 to 11.3) (4). A meta-analysis by 
Robbins-Juarez et al. reported higher mortality of 
52% of patients with severe COVID-19 infection 
with AKI and a pooled odds ratio of 15.27; 95% 
CI 4.82-48.36) .(23) Contrary to the above 
studies, Bravi et al., reported that eGFR was not 

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Res. J. Health Sci. Vol 11(4)                                                                                      301

an independent predictor of poor outcomes 
including death, however, their population was 
composed of younger patients with a higher 
prevalence of normal eGFR and fewer co-
morbidities (24). There is no doubt that mortality 
risk is increased in COVID-19 patients with 
kidney dysfunction. Reasons for the high 
mortality rate observed in our cohort are 
proffered. Mortality occurred more in the older 
patients as they tend to have higher prevalence of 
kidney diseases, more comorbidities and so 
poorer prognoses. The higher mortality observed 
in older patients with comorbidities may be 
related to a reduction in their renal functional 
reserve, an impaired capacity of their kidney to 
increase GFR in response to stress, and reduced 
functioning nephron mass (25). Chronic kidney 
disease alone, or with other comorbidities such as 
diabetes mellitus, hypertension and obesity may 
be present in some of our patients and is linked to 
increased mortality in patients with COVID-
19.(10) There was a higher occurrence of these 
comorbidities in our patients with eGFR < 
60mls/min/1.73m2. Our findings show that sex, 
severity of Covid-19, eGFR <60mls/min, WBC 
count, and use of antibiotics were significantly 
associated with mortality in the relationship. 
(table 3) 

This study has some limitations even as it 
represents a real-life setting in a tertiary health 
centre in the tropics. It was a retrospective design 
with some missing data. only those with 
creatinine values taken at admission were 
included in the study. There was no baseline 
information on kidney function (serum 
creatinine) in some patients and almost all of the 
patients had creatinine done only on admission 
and once so we could not differentiate between 
AKI or if pre-existing CKD was the case. During 
the early phase of the COVID-19 pandemic, 
available resources were focused more on 
COVID-19 infection, so kidney function was 
assessed only in patients who had symptoms, 
signs, and known risk factors of kidney disease. 
This may have led to an underestimation of 
kidney dysfunction or distorted associations 
between COVID-19 infection and kidney 
outcomes. We did not include urine analysis 
because it was not done for most of the patients. 
complicating the reliability of the diagnosis. 
Nonetheless, this study was performed in a 
tertiary-level hospital and a dedicated referral 
center for COVID-19 especially for severe 
infections in the Federal Capital Territory and 
beyond, therefore, the result can be generalisable 
locally. 

CONCLUSION
In conclusion, kidney dysfunction in our 

hospitalized patients with COVID-19 was high. 
Patients with eGFR, < 60mls/min/1.73m2 were 2 
times more likely to die than those with eGFR ≥

2
60mls/min/1.73m . Findings from our study 
underscore the importance of  looking out for 
kidney abnormalities in COVID-19 patients. 
Even though the infection and the pandemic seem 
to have subsided, it is still pertinent for clinicians 
and hospitals in Nigeria to be ready and prepared 
for future occurrences or epidemics of COVID-
19.(26, 27) Clinicians should be aware of kidney 
diseases in COVID-19 infections and monitor 
closely patients who are at risk of kidney 
involvement this may reduce mortality in these 
patients. 

Acknowledgments: We want to acknowledge 
and thank all the research assistants who 
supported and helped collate data for this study.

Source(s) of support: No funding was obtained 
for this study

Conflict of interest: The authors declare no 
conflict of interest.

Acknowledgement: Nil

Author's Contribution: MM and VK developed 
the concepts, the definition of intellectual content 
and manuscripts preparation while both the 
design of the study and the statistical analysis of 
the acquired data was done by MM. The literature 
search was carried out by MM, ZH and UG. VK, 
ZH and UG did the data acquisition. The 
manuscript editing and review was done by MM, 
VK, ZH and UG.

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Table 1: Clinico-demographic, laboratory and treatment profiles of COVID-19  
patients during hospitalization 
 
Parameters  All patients eGFR 

=60mls/min 
eGFR<60mls/min 

Total number (%) 623 427(68.5%) 196(31.4%) 
Mean eGFR mls/min  76.7±39.0 98.5± 22.6         29.1±20.0 
Mean age(years) 53.4±15.3                  50.9±15.5)          58.9±13.4 
Sex Male (%) 386(61.9) 271(63.4) 115 (58.6) 
Female  237(38) 156(36.5) 81 (41.3) 
Mean temp 0C 36.6±0.6 36.48±0.5 36.7± 0.8 
Temp >37.20C (%) 62(9.9) 27(6.3) 35(18) 
Mean Spo2. 93.1±9.7 94.5± 7.9 90.1±12.3 
MAP 100.9±14.7 101.4± 14.6 99.8± 14.9 
Severity of COVID    
Mild  196(32.0)                                       177(42.2) 19 (9.8) 
Moderate  169(27.6)                        104(24.8) 65 (33.7) 
Severe  247(40.3)        138(32.9) 109 (56.5) 
Diabetes (%) 197(31.7) 121(28.40)  76 (38.8) 
Hypertension (%) 322(51.6) 194(45.4) 128 (65.3) 
Sepsis (%)  25 (4.0) 12 (2.8) 13 (6.6) 
Median CIS 0(0,3) 0(0,0) 0(0,5) 
Laboratory     
Mean WBC 10.4± 6.5  9.4±5.9 12.4±7.4 
Median NLR ratio 2.3 (1.3,4.3) 2.06(1.2,3.8) 2.95(1.8,5.5) 
Mean Hemoglobin, g/l 12.4±2.7 12.9±2.3 11.43±3.04 
Mean HGB = 10(%) 497(84) 359(88.9 )                   138 (73.8) 
Mean HGB <10 94(15.9) 45(11.1)      49 (26.20) 
Median urea mmol/l  5.8±(4.1,9.8) 4.8 (3.7,6.5) 14.7(8.4,23.2) 
Med Creatinine umol/l 82(64, 117) 69(52, 82) 208.5(125.5,450.5) 
Mean Sodium mmol/l 138.5± 3.9 138.7± 3.3          138.1± 4.9 
Mean Potassium mmol/ 4.0± 0.5         4.0± 0.5 4.1±0.6  
Mean HCO3 22.8±3.3 23.2± 2.8         21.8±3.9 
Treatments (%)     
Antibiotics  395(64.4) 229(54.9) 166(84.7) 
Diuretics  24(3.9) 9(2.2) 15 (7.7) 
Hydroxychloroquine 118(18.9) 92 (21.6)  26 (13.3) 
Lopinavir-ritonavir  143(22.9)   130(30.4)        13 (6.6) 
Remdesevir  151(24.3) 94(22.1) 57 (29.1) 
Dexamethasone  376(60.7) 220(52.0) 156 (79.6) 
Clexane 354(56.8)                      207(48.5) 147 (75) 
Zinc  443(71.2) 323(75.8) 120 (61.2) 
Oxygen supplementation 246(39.5) 137(32.1) 109 (55.6) 
Dialysis  23(3.7) 0(0) 23/196(11.7) 
ICU admission 25(4) 7 (1.64)  18 (9.18) 
Died  108 (17.4) 45(10.5) 63 (32.1) 
Median LOS 9(6,13) 9(7,13) 9(4,13) 
Abbreviations: eGFR estimated glomerular filtration rate, MAP mean arterial pressure, Spo2 oxygen 
saturation, CIS comorbidity index score, HGB haemoglobin, ICU intensive care unit, WBC white 
blood cells, NLR neutrophil lymphocyte ratio, HCO3 bicarbonate, LOS length of stay, *Mann-
Whitney U 

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                    Number at risk 

Time(hr
s)  

0 100 200 300 400 500 600 700 

eGFR=6
0 

427   379 246 119 47 22 10 6 

eGFR<6
0 

191   141 99 49 16 8 2 2 

 
Figure 1: Kaplan-Meier curve for patient survival after hospital admission for 
COVID-19 infection according to eGFR.  
The median survival time was not defined because less than  half of the patients 
have experienced an event by day 30. 

Kidney function abnormality and risk of mortality                                                                Mamven et al.



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Table 2a: Distribution according to survival status in patients with COVID-19  
 
Parameters  Numbers  Survivors Non survivors  P-value 
 (%) N=515 (82.7%) N=108 (17.3%)  
eGFR = 60mls/min(%) 427 382(89.5)          45 (10.5)       <0.001 
eGFR <60mls/min 196 133(67.9)  63(32.1)     
Age: <60 years 392(63) 339(86.5) 53(13.5) <0.001 
= 60 years 231(37) 176(76.2) 55(23.8)  
Sex male (%) 386(62.0) 326(84.5) 60(15.5) 0.132 
Females  237(38.0) 189(79.7) 48(20.3)  
Mean temperature0C 36.6±0.6 36.5± 0.6 36.7± 0.8 0.002 
Temperature = 37.2 62(10.0) 47(75.8) 15(24.2) 0.133 
Temperature <37.2 561(90) 468(83.4) 93(16.5)  
Mean Spo2 93.1±9.7) 94.7±7.4 85.9±14.8 <0.001 
MAP 100.9±14.7 100.8±14.1 101.2±17.4 0.808 
Severity of COVID (%)     
Mild  196(31.5) 191(97.1) 5(2.5) <0.001 
Moderate  168(27.0) 149(88.7) 19(11.3)  
Severe  248(39.8) 164(66.1) 84(33.9)  
Diabetes:yes (%) 197(31.7) 152(77.2) 45(22.8) 0.011 
No  425 363(85.4) 62(14.6)  
Hypertension (%) 322(51.7) 251(77.9)       71(22.1) 0.001 
No  301 264(87.7) 37 (12.29)  
Sepsis (%)  25(4.01) 17 8(32) 0.048 
No  598 498(83.3) 100(16.7)  
Median CIS  0(0,3) 0(0,3) 0(0,5) 0.006* 
Laboratory     
Mean WBC count, 10.4±6.5 9.6±6.1 14.2±7.2 <0.001 
Median NLR  2.3 (1.3,4.3) 2.1(1.2,3.6) 3.9 (2.3,7.6) <0.001* 
Median urea mmol/l  5.8 ±(4.1,9.8) 5.5(3.9,8.6) 9(5.0,17.9) <0.001* 
Median creatinine umol/l  82(64,117) 77(62.3,108) 110(82, 352.5) <0.001* 
Mean Hemoglobin g/l 12.4± 2.7 12.53± 2.6 11.91± 2.9 0.032 
HGB = 10 (%) 497(84.1)  418(84.1) 79(15.9) 0.024 
HGB <10 (%) 94(15.1) 70(74.47) 24(25.5)  
Mean Sodium, mmol/l 138.5± 3.9 138.6± 3.6 138.1± 4.9 0.245 
Mean Potassium, mmol/l 4.05±0.6 4.03±0.5 4.16± 0.7 0.034 
Mean HCO3 22.8±3.3 22.9±3.2 22.3±3.7 0.149 
Abbreviations: eGFR estimated glomerular filtration rate, MAP mean arterial pressure, Spo2 
oxygen saturation, CIS comorbidity index score, HGB haemoglobin, ICU intensive care unit, 
WBC white blood cells, NLR neutrophil-lymphocyte ratio, HCO3 bicarbonate, LOS length of 
stay, *Mann-Whitney U 
 

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Table 2b: Treatment profile according to survival status in patients with COVID-19 
 
Parameters  Numbers  Survivors Non survivors  P-value 
  N=515 (82.7%) N=108 (17.3%)  
Treatments (%)      
Antibiotics  395(64.4) 295(74.7)       100(25.3) <0.001 
No 218 210(96.3) 8(3.7)  
Diuretics  24(3.9) 17(71 )        7(29) 0.127 
No  591 490(83) 101(17)  
Hydroxychloroquine  118(19) 105 (88.9) 13(11.9) 0.044 
No  505 410(91.2) 95(18.8)  
Lopinavir- ritonavir  143(23) 136(95.1 )           7(4.9) <0.001 
No  480 379(79)      101(21.04)  
Remdesevir  151 120 (79.5)       31(20.5) 0.242 
No  470 393(83.62) 77(16.38)  
Dexamethasone  376(61) 284(75.5)             92(24.5) <0.001 
No  243 227(93.4) 16 (6.6)  
Clexane 354 270 (76.3)       84(23.7)       <0.001 
No  269 245 (91.0) 24 (9.0)  
Zinc 443(71.2) 384 (86.7)       59 (13.3) <0.001 
No  179 130 (72.6) 49 (27.4)  
O2 supplementation 246(39.5) 166 (67.5) 80(32.5) <0.001 
No   349(92.6) 28(7.4)  
Dialysis  23(3.7) 16(69.5) 7(30.4) <0.001 
No   499(83.2) 101(16.8)  
ICU admission 25(4.0) 12(48) 13(52) <0.001 
No  598 503(84.11) 951(5.89)  
Median LOS 9(6,13) 10 (7,13) 3(1.5,6) <0.001 
Abbreviations: eGFR estimated glomerular filtration rate, MAP mean arterial pressure, 
Spo2 oxygen saturation, CIS comorbidity index score, HGB haemoglobin, ICU 
intensive care unit, WBC white blood cells, NLR neutrophil-lymphocyte ratio, HCO3 
bicarbonate, LOS length of stay, *Mann-Whitney U 
 

 
Table 3: Cox proportional analysis of the relationship between eGFR and mortality in  
COVID-19 patients. 
 Univariate analysis Multivariable analysis 
Covariate Crude-HR  95% CI P-value Adj-HR  95% CI P-value 
eGFR =60ml/min  ref   ref   
eGFR<60mls/min 3.3    2.24-4.86 <0.001      1.95    1.26-3.04 0.003      
Age <60 years ref   ref   
Age = 60 years 1.76 1.20-2.57 0.004 1.15   0.76-1.72 0.500      
Sex Male% 0.69    0.47-1.02 0.063      0.61    0.39-0.92 0.019 
Severity of disease        
Mild ref   ref   
Moderate  4.83   1.81-12.96 0.002 1.84    0.65-5.25 0.253      
Severe  15.17 6.15-37.45 <0.001      4.73    1.79-12.55 0.002      
Sepsis  1.95 0.94-4.01 0.071      1.11    0.52-2.38 0.786      
HGB =12g/l ref      
HGB 10-11.9 1.04    0.62-1.76 0.873      0.62    0.36-1.07 0.088      
HGB <10 1.64    1.01- 2.64 0.043      0.85     0.50-1.45  0.557      
WBC 1.06    1.04-1.08 <0.001      1.04    1.01-1.06 0.001      
CIS 1.07     1.02-1.12  0.009      1.03 0.98-1.09 0.180      
Temperature >37.2 1.35 0.77-2.37 0.296      0.83    0.45-1.51 0.543      
ICU admission 3.79 2.08-6.92 <0.001      1.25    0.64-2.43 0.515       
Antibiotics  7.16 3.48-14.72 <0.001      3.46    1.52-7.88                0.003      
Dialysis  1.87 0.87-4.03 0.111       0.74    0.31-1.78 0.497 
Abbreviations: eGFR estimated glomerular filtration rate, CIS comorbidity index score,  
HGB haemoglobin, ICU intensive care unit, WBC white blood cells. 

Kidney function abnormality and risk of mortality                                                                Mamven et al.