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Journal of
Personalized
Medicine
Article
Prevalence and Significance of Pyuria in Chronic Kidney
Disease Patients in Saudi Arabia
Lina Almaiman 1, †, Khaled S. Allemailem 1 ,† , Asmaa M. El-Kady 2 ,† , Mishaal Alrasheed 3,
Ahmad Almatroudi 1, Fahad S. Alekezem 3, Abdelrahman Elrasheedy 3, Wafa Abdullah Al-Megrin 4,
Hussah M. Alobaid 5and Hatem A. Elshabrawy 6, *
Citation: Almaiman, L.; Allemailem,
K.S.; El-Kady, A.M.; Alrasheed, M.;
Almatroudi, A.; Alekezem, F.S.;
Elrasheedy, A.; Al-Megrin, W.A.;
Alobaid, H.M.; Elshabrawy, H.A.
Prevalence and Significance of Pyuria
in Chronic Kidney Disease Patients in
Saudi Arabia. J. Pers. Med. 2021,11,
831. https://doi.org/10.3390/
jpm11090831
Academic Editor: David Alan Rizzieri
Received: 30 July 2021
Accepted: 22 August 2021
Published: 25 August 2021
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Copyright: © 2021 by the authors.
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This article is an open access article
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Attribution (CC BY) license (https://
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4.0/).
1Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University,
Buraydah 51452, Saudi Arabia; lenaalmaiman@gmail.com (L.A.); k.allemailem@qu.edu.sa (K.S.A.);
aamtrody@qu.edu.sa (A.A.)
2Department of Medical Parasitology, Faculty of Medicine, South Valley University, Qena 83523, Egypt;
asmaa.elkady@med.svu.edu.eg
3Department of Laboratory and Blood Bank, King Fahd Specialist Hospital, Buraydah 52211, Saudi Arabia;
hha_443@hotmail.com (M.A.); momi010@hotmail.com (F.S.A.); abdelrahmanelrasheedy@gmail.com (A.E.)
4Department of Biology, Faculty of Science, Princess Nourah bint Abdulrahman University,
Riyadh 11671, Saudi Arabia; waalmegrin@pnu.edu.sa
5Department of Zoology, College of Science, King Saud University, Riyadh 11362, Saudi Arabia;
hesalobaid@ksu.edu.sa
6Department of Molecular and Cellular Biology, College of Osteopathic Medicine, Sam Houston State
University, Conroe, TX 77304, USA
*Correspondence: hatem.elshabrawy@shsu.edu; Tel.: +1-(936)202-5216; Fax: +1-(936)202-5260
† Authors have contributed equally to the study.
Abstract:
Chronic kidney disease (CKD) is considered a major health problem, which poses a burden
for health care systems worldwide. It has been estimated that 10% of the population worldwide have
CKD; however, most of the cases are undiagnosed. If left untreated, CKD could lead to kidney failure,
which highlights the importance of early diagnosis and treatment. Pyuria has been reported in CKD
patients, and could be the result of several comorbidities, such as diabetes, or urinary tract infections
(UTIs). A few studies have shown that pyuria is associated with the late stages of CKD. However,
there are limited data on the prevalence of non-UTI (sterile) and UTI–pyuria in different CKD patient
populations, and its association with the decline in kidney function and progression of CKD. In this
retrospective study, we report the prevalence of pyuria (sterile and UTI) in 754 CKD patients of King
Fahd Specialist Hospital, Buraydah, Saudi Arabia. Our data showed that 164/754 CKD patients
(21.8%) had pyuria, whereas 590 patients (78.2%) presented with no pyuria. There was a significantly
higher percentage of late-stage (stage 4) CKD patients in the pyuric group compared to the non-pyuric
group (36.6% vs. 11.9%). In line with the previous data, proteinuria was detected in a significantly
higher percentage of pyuric patients, in addition to significantly higher levels of serum creatinine
and urea, compared to non-pyuric patients. Furthermore, 13.4% of the pyuric CKD patients had UTI,
whereas 86.6% presented with sterile pyuria. E. coli was indicated as the causative agent in 45.5% of
UTI patients. Our patient data analysis showed that a significantly higher percentage of UTI–pyuric
CKD patients, than sterile pyuric patients (63.6% vs. 19.7%), had higher numbers of urinary white
blood cells (>50/HPF, WBCs). The data also showed that a higher percentage of UTI–pyuric patients
were late-stage CKD patients, compared to sterile pyuric patients (50% vs. 34.5%). Our findings
indicate that a high level of pyuria could be considered as a marker for late-stage CKD, and that UTI
is an important risk factor for the decline in kidney function and the progression to late-stage CKD.
We believe that further studies are needed to correlate pyuria to kidney function, which could be
helpful in monitoring the progression of CKD. Moreover, the management of comorbidities, such as
diabetes and UTIs, which are risk factors for CKD and associated pyuria, could help to control the
progression of CKD to the late stages.
J. Pers. Med. 2021,11, 831. https://doi.org/10.3390/jpm11090831 https://www.mdpi.com/journal/jpm
J. Pers. Med. 2021,11, 831 2 of 9
Keywords:
CKD; pyuria; UTI; E. coli; WBCs; urine; leukocyte esterase; albuminuria; urinary
nitrite; bacteria
1. Introduction
Chronic kidney disease (CKD) is one of the leading causes of death in the United
States [
1
]. Several studies, in Africa, Asia, Australia, Europe, and South and North America,
have also shown the high burden of this disease in several countries [
2
]. In Saudi Arabia,
the prevalence of CKD is around 5.7% and it is considered the fourth leading cause of
death, with a mortality rate of 5.44% [3].
CKD could be a risk factor for urinary tract infections (UTIs), which can manifest as
asymptomatic bacteriuria or symptomatic UTIs that require treatment [
4
]. It is believed that
CKD compromises innate and adaptive immune responses, which renders CKD patients
more susceptible to infections, including UTIs [
5
]. Diabetes, obstructions in the urinary
tract, and old age, are known to increase the risk of UTI, CKD, and its progression to the
late stages [
6
]. If left undiagnosed or untreated, UTI could result in significant deterioration
in renal function, advanced stages of CKD, nephrectomy, and death [7–9].
Pyuria is a useful marker for UTIs in the general population, especially in symptomatic
patients; however, pyuria may also present in the absence of UTIs, such as in the cases of
structural abnormalities of the genitourinary tract or interstitial nephritis [
4
,
10
]. Pyuria has
also been described in CKD patients, in the presence and in the absence of UTIs (sterile
pyuria) [
10
,
11
]. To the best of our knowledge, sterile pyuria is more prevalent in the CKD
patient population than in the non-CKD population, and it positively correlated with CKD
stage [
10
,
11
]. Studies have shown that the prevalence of sterile pyuria among CKD patients
was in the range of 31–72% [
12
–
17
]. This may be explained by chronic renal parenchymal
inflammation, due to comorbidities such as diabetes and hypoalbuminemia [
12
,
13
]. Fur-
thermore, 25–45% of pyuric CKD patients could also present with UTI, which could be a
complication of CKD, or comorbidities such as diabetes [
4
,
6
,
12
,
16
,
18
]. It has been reported
that UTI–CKD patients had high levels of pyuria and that pyuria associated with advanced
stages of CKD [
4
,
10
]. However, the association between pyuria and the decline in kidney
function needs further investigation.
Despite all the previous studies, there are limited studies on the prevalence of sterile
and UTI pyuria among CKD patients of different populations. In the present study, we
aimed to study the prevalence of sterile and UTI pyuria in CKD patients of the King
Fahd Specialist Hospital, Buraydah, Qassim, Saudi Arabia, in the period from March to
December 2020. We also attempted to assess the association between pyuria and the late
stages of CKD.
2. Materials and Methods
2.1. Study Population
The present study is a single-center, retrospective, cross-sectional study that was
conducted at the King Fahd Specialist Hospital, Buraydah, Qassim, Saudi Arabia. All
CKD patients (754 patients) who attended the outpatient nephrology clinic in the period
from March to December 2020, were included in the study. CKD was classified into stage
I (kidney damage with normal or increased kidney function) with glomerular filtration
rate (GFR)
≥
90, stage II (kidney damage with mildly diminished kidney function) with
GFR between 60 and 89, stage III (moderately reduced kidney function) with GFR between
30 and 59, stage IV (severely decreased kidney function) with GFR between 15 and 29, and
stage V is considered as (kidney failure) with GFR < 15 [19].
Demographic data (age, gender, stage of CKD and comorbidities such as diabetes
mellitus, hypertension, chronic pulmonary diseases, malignancy, chronic organ failure, etc.)
and laboratory results (including complete urine analysis (presence of red blood cells and
white blood cells in urine sediment, proteinuria, presence of nitrite, leukocyte esterase),
J. Pers. Med. 2021,11, 831 3 of 9
kidney function tests, hemoglobin, and urine culture) were retrieved from the electronic
patients’ records.
Pyuria was defined as
≥
5 WBCs per high-power field (HPF) of centrifuged urine
examined by microscopy, which is still considered the standard method [
20
]. Hematuria
was defined as
≥
5 red blood cells/HPF of urine examined by microscopy. Proteinuria
was defined as the presence of
≥
1+ protein in urine using dipstick analysis. Presence
of urinary nitrites and urinary leukocyte esterase were determined using urine dipstick
analysis. Pyuria with significant bacteriuria (
≥
10
5
colony forming units/mL (CFU/mL))
was defined as UTI, whereas pyuria without significant bacteriuria (<10
5
CFU/mL) was
defined as sterile pyuria.
2.2. Statistical Analysis
Data analysis was carried out using the IBM SPSS 20.0 software (SPSS Inc., Chicago, IL,
USA). Continuous variables were expressed as mean
±
standard deviation (SD). Categori-
cal data were expressed as numbers and percentages. Statistical analyses were performed
using Mann–Whitney U test or chi-square test for continuous and categorical variables,
respectively. The pvalues < 0.05 were considered statistically significant.
3. Results
3.1. Patients’ Characteristics
Seven hundred and fifty-four (754) CKD patients, included in the present study, were
categorized according to the CKD stage, into stage 3 (32.4%), stage 1 (28.1%), stage 2
(22.3%), and stage 4 CKD patients (17.2%) (Figure 1). The age of the patients ranged from
14 to 95 years (mean
±
SD = 56
±
17), with a majority being males (62.6%). The medical
histories showed that 74.8% of the CKD patients are hypertensive, whereas 57.4% have
diabetes. Moreover, urine analysis revealed that 48.5% of the patients had albuminuria
upon dipstick examination, 2.9% had urinary tract infection, 20.3% showed hematuria,
2.3% were positive for nitrite, whereas 16.6% were positive for leukocyte esterase (Table 1).
The serum urea and creatinine were higher than normal, which correlates with the CKD
condition of these patients.
J. Pers. Med. 2021, 11, x FOR PEER REVIEW 3 of 9
and white blood cells in urine sediment, proteinuria, presence of nitrite, leukocyte ester-
ase), kidney function tests, hemoglobin, and urine culture) were retrieved from the elec-
tronic patients’ records.
Pyuria was defined as ≥5 WBCs per high-power field (HPF) of centrifuged urine ex-
amined by microscopy, which is still considered the standard method [20]. Hematuria
was defined as ≥5 red blood cells/HPF of urine examined by microscopy. Proteinuria was
defined as the presence of ≥1+ protein in urine using dipstick analysis. Presence of urinary
nitrites and urinary leukocyte esterase were determined using urine dipstick analysis. Py-
uria with significant bacteriuria (≥10
5
colony forming units/mL (CFU/mL)) was defined as
UTI, whereas pyuria without significant bacteriuria (<10
5
CFU/mL) was defined as sterile
pyuria.
2.2. Statistical Analysis
Data analysis was carried out using the IBM SPSS 20.0 software (SPSS Inc., Chicago,
IL, USA). Continuous variables were expressed as mean ± standard deviation (SD). Cate-
gorical data were expressed as numbers and percentages. Statistical analyses were per-
formed using Mann–Whitney U test or chi-square test for continuous and categorical var-
iables, respectively. The p values < 0.05 were considered statistically significant.
3. Results
3.1. Patients’ Characteristics
Seven hundred and fifty-four (754) CKD patients, included in the present study, were
categorized according to the CKD stage, into stage 3 (32.4%), stage 1 (28.1%), stage 2
(22.3%), and stage 4 CKD patients (17.2%) (Figure 1). The age of the patients ranged from
14 to 95 years (mean ± SD = 56 ± 17), with a majority being males (62.6%). The medical
histories showed that 74.8% of the CKD patients are hypertensive, whereas 57.4% have
diabetes. Moreover, urine analysis revealed that 48.5% of the patients had albuminuria
upon dipstick examination, 2.9% had urinary tract infection, 20.3% showed hematuria,
2.3% were positive for nitrite, whereas 16.6% were positive for leukocyte esterase (Table
1). The serum urea and creatinine were higher than normal, which correlates with the
CKD condition of these patients.
Figure 1. Categorization of patients according to stage of chronic kidney disease (CKD). Most of
patients were diagnosed as stage 3 CKD patients (33%) followed by stage 1 (28%), stage 2 (22%),
and stage 4 (17%).
Stage 1
28.1%
Stage 2
22.3%
Stage 3
32.4%
Stage 4
17.2%
Stage 1 Stage 2 Stage 3 Stage 4
Figure 1.
Categorization of patients according to stage of chronic kidney disease (CKD). Most of
patients were diagnosed as stage 3 CKD patients (33%) followed by stage 1 (28%), stage 2 (22%), and
stage 4 (17%).
J. Pers. Med. 2021,11, 831 4 of 9
Table 1.
Demographic, clinical and laboratory data of chronic kidney disease (CKD) patients. CKD
patients’ demographic and clinical data are shown and expressed as numbers (N) and percentages
(%) or as mean ±SD.
Patients’ Characteristics N= 754
56 ±17
Age (Years; Mean ±SD)
N%
Gender Male 472 62.6
Female 282 37.4
CKD Stage
Stage 1 212 28.1
Stage 2 168 22.3
Stage 3 244 32.4
Stage 4 130 17.2
Diabetes 433 57.4
Hypertension 564 74.8
Albuminuria 366 48.5
Hematuria 153 20.3
Urinary Tract Infection (UTI) 22 2.9
Urinary Leukocyte Esterase 125 16.6
Urinary Nitrite 17 2.3
Mean ±SD
Serum Urea (mmol/L) 10.8 ±7.9
Serum Creatinine (µmol/L) 192.5 ±146.2
Hemoglobin (g/dL) 13.02±2.23
3.2. Pyuric CKD Patients Are in Later Stages of CKD and Could Present with UTI Compared to
Non-Pyuric Patients
Our results show that 164 CKD patients (21.8%) had pyuria, with a significantly higher
percentage of females (68.9% vs. 28.6%) and a lower percentage of males (31.1% vs. 71.4%),
compared to the non-pyuric CKD patients (Table 2). There was no significant difference
between the mean age of the pyuric and non-pyuric CKD patients. However, there was
a significantly higher percentage of late-stage (stage 4) CKD patients in the pyuric group
compared to the non-pyuric group of patients (36.6% vs. 11.9%; p= 0.002). This finding
indicates that the existence of pyuria in CKD patients could be diagnostic for the late stages
of CKD.
Next, we compared the clinical and laboratory characteristics of pyuric and non-
pyuric CKD patients. Our results showed that significantly higher percentages of pyuric,
than non-pyuric, CKD patients, had proteinuria (albuminuria), p= 0.001. The prevalence
of proteinuria (64%), and the significantly higher levels of serum urea (p= 0.006) and
creatinine (p= 0.001) in the pyuric patients, compared to the non-pyuric patients, corre-
lates with higher percentage of late-stage CKD patients in the pyuric group compared
to the non-pyuric group. Consistent with the existence of pyuria, a significantly higher
percentage of pyuric patients tested positive for urinary leukocyte esterase compared to
non-pyuric patients (67.7% vs. 2.4%; p= 0.002). Unlike the non-pyuric patients, who
presented with no UTI, 13.4% of the pyuric patients had UTI, which resulted in a signifi-
cantly higher percentage of pyuric patients testing positive for urinary nitrite compared to
non-pyuric patients (7.9% vs. 0.7%; p= 0.002). Our data report a significantly higher per-
centage of hematuric pyuric patients than hematuric non-pyuric patients (43.9% vs. 13.7%;
p= 0.004), which indicates that pyuria could be associated with hematuria. Additionally,
we found that comorbidities, such as diabetes and hypertension, were more prevalent in
the non-pyuric group than in the pyuric group (Table 2).
J. Pers. Med. 2021,11, 831 5 of 9
Table 2.
Characteristics of pyuric and non-pyuric CKD patients. Demographic, clinical, and laboratory data of pyuric
(N= 590) and non-pyuric patients (N= 164) are presented as numbers (N) and percentages (%) or means
±
SD. The
p-values < 0.05 were considered statistically significant.
Variables No Pyuria
N= 590
Pyuria
N= 164 p-Value
Age (years; mean ±SD) 56.2 ±16 53.2 ±19.5 0.151
N%N%
Gender Male 421 71.4 51 31.1 0.001
Female 169 28.6 113 68.9
CKD Stage
Stage 1 183 31 29 17.7
0.002
Stage 2 137 23.2 31 18.9
Stage 3 200 33.9 44 26.8
Stage 4 70 11.9 60 36.6
Diabetes 353 59.8 80 48.8 0.008
Hypertension 455 77.1 109 66.5 0.004
Albuminuria 261 44.2 105 64 0.001
Hematuria 81 13.7 72 43.9 0.004
Urinary Tract Infection (UTI) 0 0 22 13.4 0.003
Urinary Leukocyte Esterase 14 2.4 111 67.7 0.002
Urinary Nitrite 4 0.7 13 7.9 0.002
Mean ±SD
Serum Urea (mmol/L) 10 ±6.7 13.8 ±10.7 0.006
Serum Creatinine (µmol/L) 175.9 ±136.9 252.5 ±228.7 0.001
Hemoglobin (g/dL) 13.32 ±2.209 11.98 ±1.963 0.001
3.3. Several Bacterial Species Were Associated with UTI in 22 Pyuric CKD Patients with E. coli
Being the Most Common Causative Agent
As previously shown in Table 2, 22 out of our 164 pyuric CKD patients (13.4%)
were diagnosed with UTI. The most common causative agent of UTI in our patients was
Escherichia coli (E. coli) (10 out of 22 (45.5%) UTI patients). Several other microorganisms
were reported as UTI causative agents (Table 3).
Table 3.
Escherichia coli (E. coli) is the most common causative agent of urinary tract infections (UTIs)
in pyuric CKD patients. The microbial causative agent associated with each UTI case was retrieved
from patients’ electronic medical records. The number of patients infected with each microbial species
was recorded.
Organism Number of Patients
Acinetobacter lwoffii 1
Candida Species 1
Citrobacter freundii 1
E. coli 10
Staphylococcus aureus 1
Enterococcus fecalis 2
Klebsiella pneumoniae 3
Pseudomonas Aeruginosa 2
Salmonella Species 1
Total 22
3.4. Pyuric CKD Patients Diagnosed with UTI Have Increased Numbers of Urinary WBCs and
Are in Later Stages of CKD Compared to Sterile Pyuric CKD Patients
As previously mentioned, 13.4% (22 patients) of pyuric CKD patients had UTI, whereas
86.6% (142 patients) were sterile pyuric patients. Next, we compared the demographics
and various clinical parameters of sterile pyuric and UTI–pyuric CKD patients (Table 4).
There were no significant differences in the mean age (p= 0.095) and gender distribution
J. Pers. Med. 2021,11, 831 6 of 9
(p= 0.063) between the sterile and UTI–pyuric patients. As expected, a significantly higher
percentage of UTI–pyuric patients had a high number (>50/HPF) of urinary white blood
cells (WBCs) compared to sterile pyuric patients (63.6% vs. 19.7%; p= 0.002). Furthermore,
a significantly higher percentage of UTI–pyuric patients than sterile pyuric patients had an
advanced stage of CKD (50% vs. 34.5%; p= 0.004). Interestingly, the sterile pyuric group
had a significantly higher percentage of patients with late-stage CKD than non-pyuric
patients (34% vs. 11.9%; p< 0.05) (Tables 2and 3). The previous findings confirm that a
high level of pyuria is a significant indicator of late-stage CKD. The significantly higher
percentage of urinary leukocyte esterase-positive UTI–pyuric patients (86.4%; p= 0.002)
confirmed our finding of a higher number of urinary WBCs in a significant percentage of
these patients. Moreover, the significantly higher percentage of urinary nitrite-positive
patients among the UTI–pyuric patients, compared to the sterile pyuric patients (18.2% vs.
6.3%; p= 0.003), confirmed the infection status of these patients. There were no significant
differences in the prevalence of diabetes, hypertension, and proteinuria, or the levels of
serum urea, creatinine, and hemoglobin, between the UTI and sterile pyuric CKD patients
(p> 0.05). The nonsignificant difference in the percentage of proteinuria patients, and levels
of serum urea and creatinine, between the UTI–pyuric and sterile pyuric patients, despite
the higher percentage of late-stage CKD patients in the UTI–pyuric group, may be due to
a smaller number of UTI–pyuric patients compared to sterile pyuric patients (22 vs. 142).
Overall, our findings indicate that UTI is an important risk factor for the late stages of CKD,
and these late stages of CKD could be predicted by detecting high numbers of urinary
WBCs (>50/HPF; high pyuria).
Table 4.
Comparison of demographic and clinical parameters of UTI and sterile pyuric CKD patients.
Demographic, clinical, and laboratory data of UTI–pyuric (N= 22) and sterile pyuric patients
(N= 142) were collected and presented as numbers (N) and percentages (%) or means
±
SD. The
p-values < 0.05 were considered statistically significant.
Variables UTI Sterile Pyuria p-Value
N= 22 N= 142
Age (years; mean
±SD) 55 ±22 53 ±19 0.095
N%N%
Gender Males 7 31.8 44 31 0.063
Females 15 68.2 98 69
CKD Stage
Stage 1 2 9.1 27 19.1
0.004
Stage 2 3 13.6 28 19.9
Stage 3 6 27.3 38 27
Stage 4 11 50 49 34.5
Urinary
WBCs/HPF
5–9 4 18.2 44 31
0.002
10–19 3 13.6 39 27.5
20–49 1 4.6 31 21.8
>50 14 63.6 28 19.7
Diabetes 12 54.5 68 44.7 0.6
Hypertension 13 59.1 96 67.6 0.44
Albuminuria 14 63.6 91 64.1 0.353
Hematuria 8 36.4 64 45.1 0.037
Urinary Nitrite 4 18.2 9 6.3 0.003
Urinary Leukocyte Esterase 19 86.4 92 64.8 0.002
Mean ±SD
Serum Urea (mmol/L) 17.1 ±10.4 13.3 ±10.7 0.072
Serum Creatinine (µmol/L) 269.05 ±206.62 250.08 ±232.49 0.061
Hemoglobin (g/dL) 13.08 ±2.212 11.27 ±2.021 0.121
J. Pers. Med. 2021,11, 831 7 of 9
4. Discussion
CKD is a growing health care issue that is associated with the expenditure of millions
of dollars, resulting in a huge burden on the economy and health care systems [
21
,
22
].
According to CDC, the 2018 Medicare spending on CKD patients was USD 81.8 billion or
USD 23,700 per person. It has been estimated that 37 million adults in the United States
(US) have CKD, of which most cases are undiagnosed. Diabetes and high blood pressure
are important risk factors for CKD [23].
Pyuria (the presence of WBCs in urine) is a common presentation in CKD patients,
and could exist in the presence or absence of UTI (sterile pyuria) [
10
,
11
]. Pyuria in CKD
patients is believed to be the result of renal parenchyma inflammation, which could be
exacerbated by advanced age, female gender, diabetes, hypoalbuminemia, and UTI [
4
].
The existence of UTI in some CKD patients could be the deleterious effect of comorbidities,
such as diabetes, urinary tract obstruction, and advanced age, all of which increase the risk
of UTI [
6
]. However, CKD itself is believed to be a risk factor for UTI, due to impairment
of cellular and humoral immunity [
24
]. Despite the prevalence of pyuria in CKD patients,
the association between pyuria and the deterioration of kidney function in CKD patients is
not well understood.
In the present study, our data showed that 164 CKD patients (21.8%) had pyuria. This
is in agreement with previous reports, which showed the prevalence of pyuria (31–72%)
among CKD patients [
12
–
17
]. Furthermore, our results showed that a significantly higher
percentage of CKD pyuric patients, than non-pyuric CKD patients, were late-stage CKD
patients (stage 4). These results are in agreement with studies that showed that 17.5% of late-
stage CKD patients had pyuria, and that pyuria is an indicator of the deterioration of kidney
function in patients with autosomal dominant polycystic kidney disease (ADPKD) [4,8].
Sterile pyuria was more predominant in our CKD patients compared to UTI-associated
pyuria (142 sterile pyuric patients (86.6%) vs. 22 UTI pyuric patients (13.4%)). Few studies
reported the prevalence of UTI among CKD patients; however, the authors suggested
that the frequency of UTI is quite similar to that in the general population [
24
]. Our data
showed that a significantly higher percentage of UTI, than sterile pyuric patients (63.6% vs.
19.7%), had higher pyuria (>50 WBCs/HPF). This finding is consistent with another study,
which showed that the degree of pyuria was associated with UTI in CKD patients [
10
]. In
addition, a significantly higher percentage of UTI, than sterile pyuric CKD patients, were
late-stage CKD patients (50% vs. 34.5%). Other studies have shown that UTI may result in
acute kidney injury (AKI) and, eventually, CKD [
25
]. Several mechanisms that are involved
in UTI-mediated kidney injury have been described, including renal parenchyma infection
and sepsis [
26
,
27
]. Our findings indicate that pyuria is an important indicator of the decline
in kidney function in CKD patients, which is supported by a previous study that concluded
that pyuria precedes UTI and the subsequent deterioration of kidney function in ADPKD
patients [
8
]. Furthermore, our findings support the need for the early management of UTIs
and other comorbidities in CKD patients, to prevent the decline in kidney function, and
indicates that pyuria could be used to monitor the progression of CKD.
Author Contributions:
Conceptualization, L.A., K.S.A., A.M.E.-K., H.A.E.; experimental design and
methodology, L.A., K.S.A., A.M.E.-K., W.A.A.-M., H.M.A., H.A.E.; writing—original drafts, L.A.,
K.S.A., A.M.E.-K., H.A.E.; data collection, L.A., K.S.A., A.M.E.-K., M.A., F.S.A., A.E.; data analysis,
L.A., K.S.A., A.M.E.-K., A.A., W.A.A.-M., H.M.A., H.A.E.; writing—review and editing, L.A., K.S.A.,
A.M.E.-K., A.A., W.A.A.-M., H.MA., H.A.E.; investigation, K.S.A., A.M.E.-K., H.A.E.; supervision,
H.A.E.; project administration, H.A.E.; critical revisions and writing, H.A.E. All authors have read
and agreed to the published version of the manuscript.
Funding: This research received no external funding.
Institutional Review Board Statement:
The study was conducted according to the guidelines of
the Declaration of Helsinki and approved by the local ethics committee and the Scientific Research
Platform of the Ministry of Health in Saudi Arabia (protocol code: 1442-1689182).
J. Pers. Med. 2021,11, 831 8 of 9
Informed Consent Statement:
Informed consent was waived since this was a retrospective study
without patients’ identifiers.
Data Availability Statement: Not applicable.
Acknowledgments:
This research was funded by the Deanship of Scientific Research at Princess
Nourah bint Abdulrahman University through the Fast-Track Research Funding Program and
Researchers Supporting Project (project no.: RSP-2021/174) from King Saud University, Riyadh,
Saudi Arabia.
Conflicts of Interest: The authors declare no conflict of interest.
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