Pattern of Urinary Sediments and Comparison

8/10/2019 Pattern of Urinary Sediments and Comparison

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INTRODUCTION

Systemic hypertension is a major health problem world-

wide and Blacks are more prone to its complications (1,

2). About 4.33 million Nigerians aged 15 years and above,

corresponding to 9.3% of the population, are hypertensive

based on a systolic blood pressure of 160 mmHg and a

diastolic pressure of 90 mmHg (3, 4). However, when the

World Health OrganizationInternational Society of Hyper-

tension (WHO/ISH) guidelines of 1999 were applied to the

above data, the estimated prevalence of hypertension was

17% to 20% or more (5, 6). Although the prevalence rate is

lower than the figure reported for the United States (>25%)

(7), the mortality associated with the disease in Nigeria has

been observed to be higher (8). Hypertension has a cause

and effect relationship with kidney disease and is a major

factor responsible for progression to End-Stage Renal Dis-

ease (ESRD) (9-12). The risk factors that have been found

to predispose hypertensive to developing ESRD include:

Black race, positive family history, long-standing or severe

hypertension, age of onset of hypertension between 25 and

45 years old, presence of hypertensive retinopathy, and left

ventricular hypertrophy (13). Many studies in Nigeria have

shown that hypertension and chronic glomerulonephritis

topped the list of common causes of chronic renal failure

(CRF) (14-16). In a prospective study of 1,980 patients,

Ojogwu (16)observed that the most common cause (43%

of cases) of chronic renal failure was hypertensive nephro-

sclerosis. This was followed by obstructive uropathy (33%)

and chronic glomerulonephritis (18%). He observed that

the frequency and severity of hypertension in Nigerians and

their propensity to develop renal failure are similar to what

obtains in American Blacks. Similarly, Akinsola et al (17)

reported that hypertension was second to chronic glom-

erulonephritis as a cause of chronic renal failure, the care

of which is unaffordable to the majority of patients. This

underscores the need to emphasize strategies for prevent-

ing the development of progressive renal disease with early

recognition of clinical markers of chronic kidney disease

ABSTRACT

Background: Urinary sediment examination and dip-

stick urinalysis are an integral part in evaluating hy-

pertensive patients. This study aims to determine theprevalence of urinary sediment abnormalities and

compare this result with dipstick urinalysis in hyper-

tensive Nigerians.

Methods: 138 newly diagnosed, adult, hypertensive

Nigerians were studied. They were compared with

an age- and sex-matched non-hypertensive control

group from the general population. The subjects urine

samples were analyzed by dipstick test and micros-

copy (bright field), enhanced by Sternheimers stain.

Significant sediments were defined as 3/hpf and dip-

stick proteinuria or hematuria as 1+.

Results: Mean age was 43.219.64 yrs and 43.199.55

yrs in patients and controls respectively with 76 (55%)males in the patients and 80 (58%) in controls. Micro-

scopic hematuria (3/hpf) was detected in 15.2% of

the patients and 3.6% of the control group (p=0.0009).

Other elements present in insignificant quantities

in patients and controls, respectively, were: leuko-

cytes (7.2%, 9.4%, p=0.513); hyaline casts (5.8%,

8%, p=0.476), granular casts (1.4%, 0%) and crystals

(6.5%, 5.1%, p=0.606). Dipstick proteinuria with he-

maturia was found in 6.55% and proteinuria alone in

1.45% of cases, while the control group showed 2.2%

and 1.45% of hematuria and proteinuria, respectively;

47.6% of hypertensive patients with urinary sediment

hematuria were not detected by dipstick test.Conclusions: Hypertensive Nigerians showed a high

prevalence of microscopic hematuria which may be

suggestive of sub-clinical kidney damage at diagno-

sis. There is a high false-negative rate with dipstick

urinalysis, underscoring the need for routine examina-

tion of urinary sediment in the assessment of hyper-

tensive patients.

Key words: Dipstick tests, Hypertension, Nigerians,

Urinary sediments

Division of Nephrology, Department of Medicine,

University of Ilorin Teaching Hospital, Ilorin - Nigeria

Division ofNephrology, DepartmentofMedicine, University ofIlorin TeachingHospital, Ilorin -Nigeria

Timothy O. Olanrewaju, Ademola Aderibigbe

Pattern of urinary sediments and comparison

with dipstick urinalysis in hypertensive Nigerians

ORIGINAL ARTICLE


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Olanrewaju and Aderibigbe: Urinary sediment evaluation in hypertension

(18). In a developing nation like Nigeria, such strategies

involve a simple urine test to detect early renal damage.

Early detection of patients with glomerulonephritis will at-

tract appropriate intervention measures to prevent or delay

progression to ESRD.

There are many markers for assessing renal damage.

These range from very sensitive endogenous markers such

as cystatin C, microalbuminuria and proteinuria to serum

urea, creatinine, uric acid, creatinine clearance and uri-

nary sediment. While some of these markers are indeed

sensitive, they can be expensive as a screening tool for

early detection of renal damage. The examination of uri-

nary sediments under the microscope for abnormalities is

a recognized method for assessing renal damage irrespec-

tive of the cause,and some characteristic features of the

sediment have been used to determine the type and pos-

sibly the severity of renal disease (19). The findings in the

sediment of red blood cells or red blood cell casts, white

blood cells or white blood cell casts, oval fat bodies or fatty

casts and broad casts are almost diagnostic of glomeru-

lonephritis, pyelonephritis, nephritic syndrome and renal

failure, respectively (19). Thus, urinary sediment analysis

tends to give information about the etiology of renal dis-

eases, helps in prognostication, and may offer a simpler

index for evaluating the stage of renal damage in patients

with newly diagnosed hypertension. The facilities are read-

ily available, the samples can be collected anywhere and

its collection is noninvasive. Urinary sediment examination

has therefore been recommended for evaluation of hyper-

tension in order to determine the cause and/or effect rela-

tionship (5, 20, 21).

Though some studies have been done on urinary abnormali-

ties in Nigeria, most of them were carried out on children and

adolescents using dipstick urinalysis (22-26). There is pau-

city of published studies on urinary sediments among Nige-

rians and in particular, adult hypertensive patients. Hence

this study was designed to evaluate the pattern of urinary

sediments and compare the results with dipstick urinalysis

in newly diagnosed, adult Nigerian hypertensive patients.

MATERIALSANDMETHODS

Study design and location

This was a cross-sectional study of consecutively recruit-

ed, consenting patients. The study was carried out at the

General Out-patient Department (GOPD), Medical Outpa-

tient Department (MOPD), Accident and Emergency (A/E)

Department of the University of Ilorin Teaching Hospital

(UITH) and the Federal Staff Clinic at the Federal Secre-

tariat in Ilorin. Ilorin is the capital city of Kwara State, which

is one of the states in the north-central zone of Nigeria.

UITH Ilorin serves both Kwara State as well as five other

adjoining states.

Selection of subjects

The inclusion criteria for patients were newly diagnosed,

adult hypertensive patients aged 18 years and above with

average systolic blood pressure of 140 mmHg and/or a

diastolic pressure of 90 mmHg who were not on drugs

and who consented to the study by filling in the consent

form. The exclusion criteria included (i) patients with dia-

betic mellitus, sickle cell disease, history of/or established

renal disease, malignancy and clinical evidence of connec-

tive tissue disease; (ii) women who are pregnant, in peupe-

rium or those menstruating; (iii) patients who are on anti-

hypertensive drugs; and (iv) those who have just completed

rigorous exercise or are on any medications. For the control

group, the inclusion criteria were healthy, non-hypertensive,

age- and sex-matched individuals who have not undergone

rigorous exercise; and the exclusion criteria included indi-

viduals with high blood pressure and those that fulfilled the

exclusion criteria as stated for the subject group.

Ethical clearance

An approval was obtained from the ethical and research

committee of the University of Ilorin Teaching Hospital be-

fore commencing the study. All patients and controls who

participated in the study signed the informed consent be-

fore recruitment.

Evaluation and investigation protocols

Clinical

Detailed biodata and socio-demographic parameters were

obtained from the patients and controls using structured

questionnaires. Weight (WT) was measured using the por-

table SECA weighing scale placed on a flat, hard surface

with the subjects wearing light clothing and height mea-

sured with subjects standing without shoes. Body mass in-

dex was calculated from height and weight. Blood pressure

was measured in sitting position with a mercury sphygmo-

manometer with standard cuff (25 cm x 12 cm) on the right

arm after 5 minutes of rest. Korotkoff phases I and V were

taken as systolic blood pressure (SBP) and diastolic blood

pressure (DBP), respectively. Hypertension was defined


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based on the Seventh Report of the Joint National Commit-

tee on Prevention, Detection, Evaluation and Treatment of

High Blood Pressure (JNC VII) (1). Two measurements were

taken at least 5 minutes apart and the value of the mean

was used for the study. The mean arterial pressure (MAP)

and pulse pressure (PP) were also determined.

Serum biochemistry and urineculture

Blood samples for urea and creatinine were collected in

heparinized bottles and analyzed at the Chemical Pathol-

ogy Laboratory of the hospital using an RA-50 spectro-

photometer (Bayer, Germany). Urea (Ur) was analyzed by

diacetyl monoxime method while Jaffes reaction was used

for creatinine (Cr). Also, fasting plasma glucose (FPG) sam-

ples were collected in a fluoride oxalate bottle and ana-

lyzed at the same laboratory by glucose oxidase method.

Urine culture was done to exclude urinary tract infections.

Glomerular filtration rate (GFR) was estimated by the Cock-

roft and Gault formula which has been validated in Nigerian

patients (27).

Dipstick urinalysis

About 10 mL of early morning, clean catch urine was col-

lected in a sterile test tube. The urine was examined physi-

cally and tested with urinanalysis reagent strips (Multistix

10 SG; Bayer, Leverkusen, Germany). Each parameter

tested (e.g., protein, blood, leukocytes, and nitrite) was read

manually within the specified time limit as indicated by the

manufacturer of the dipsticks. Protein 1 + and blood more

than trace were considered to be significant.

Urine sediment microscopy

This procedure was carried out in the renal laboratory by the

investigator with the assistance of an experienced laborato-

ry technologist. A standard urinary sediment Atlas produced

by Fogazzi et al (19) was used for clarification as deemed

necessary. A 10 mL early morning, first void, clean catch

urine was collected in a sterile tube and centrifuged for 5

minutes at 2000 rpm. The supernatant was decanted leav-

ing approximately 0.5 mL volume of the sediment. In order

to enhance the identification of the constituent elements

of the sediment, Sternheimers stain was applied. Stern-

heimers stain is one of the most popular supravital stains

which, in the absence of a phase contrast microscope,

helps to partly overcome the limitations of the bright field

microscope (28). It is a mixture of Copper-phthalocyanine

dye, national fast blue and a xanthene dye called pyronin

B. A drop of this stain was added to the 0.5 mL sediment

and left for 10 minutes to allow the staining to develop and

increase in intensity. This enhances a good differentiation of

red blood cells, white blood cells, epithelial cells, and casts.

The stained urine sediment was resuspended by gentle agi-

tation and a drop was pipetted using a micropipette onto a

clean glass slide and covered with a clean cover-slip. The

sediment was then examined under the bright-field micro-

scope, first under low (x 100 magnifications) and then high

power (x 400 magnifications). Ten to fifteen fields were ex-

amined in the low and high power objectives. Each of the

constituent elements of the sediment was recorded as an

average number per high power field (hpf). The presence of

sediment cells >2/hpf and casts or crystals as indicated by

a plus (+) were considered significant.

Data analysis

The data were analyzed by SPSS version 12.0.1 (SPSS Inc.,

Chicago, IL, USA). Means and standard deviations were

used to summarize numerical/quantitative variables. The

statistical significance of differences in patients and con-

trol groups was estimated using chi-square for categorical

variables and Students t-test for continuous variables. The

proportion of patients with abnormal urinary sediment was

determined. The level of statistical significance was taken

as a p value of < 0.05.

RESULTS

The demographic, clinical and laboratory characteristics

of the patients and control subjects are shown in Table

I. There was no difference between the mean age of the

patients and the control subjects, showing that they were

well matched. There was also no difference in the fasting

plasma glucose between the two groups. However, the pa-

tient group had significantly higher values of weight, BMI,

SBP, DBP, MAP and PP than control subjects (p2/hpf) with a range of

3-10/hpf. In the control group, 119 (86.2%) had no RBC,

14 (10.2%) had 1-2/hpf and only 5 (3.6%) had > 2/hpf of

RBCs in the urinary sediment (Fig. 1). The difference in the


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microscopic hematuria between the patients (15.2%) and

controls (3.6%) was significant (p=0.001).White blood cells

(WBC) of 1-2/hpf were detected in 10 (7.2%) of the pa-

tients while the remaining 128 (92.8%) had no WBC. In the

control group, 13 (9.4%) had 1-2/hpf of WBC while 125

(90.6%) had no WBC (Fig. 2). Granular casts of 1-2/hpf

Fig. 1 - Urinary sediment red blood cells per high power field(hpf) in study subjects. White columns = patient; black col-umns = control.

Fig. 2 - Urinary sediment white blood cells per high powerfield (hpf) in study subjects. White columns = patient; blackcolumns = control.

TABLE I

CLINICAL AND LABORATORY CHARACTERISTICS OF THE SUBJECTS

Characteristics Patients Control p value

Age (years) 43.21 9.64 43.19 9.55 0.9862

Gender: male, n (%) 76 (55) 80 (58)

Weight (Kg) 72.63 14.29 69.34 12.55 0.0431

Body Mass Index (kg/m2) 26.18 5.12 23.34 9.02 0.0015

Systolic Blood Pressure (mmHg) 154.32 17.2 119.44 11.94 < 0.001

Diastolic Blood Pressure (mmHg) 98.67 16.87 76.11 6.14 < 0.001

Pulse Pressure (mmHg) 59.64 19.79 43.33 11.32 < 0.001

Mean Arterial Pressure (mmHg) 114 14.21 90.55 6.65 < 0.001

Urea (mmol/L) 5.27 1.39 4.86 1.24 0.0102

Creatinine (umol/L) 76.06 22.49 67.55 15.9 0.0003

Fasting plasma glucose (mmol/L) 4.12 1.23 96 1.29 0.2926

Glomerular filtration rate (ml/min/1.73m2) 107.6 0 52.85 122.17 44.3 0.0134


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were present in only 2 (1.4%) of the patients and none in the

control subjects, while hyaline casts of 1-2/hpf were found

in 8 (5.8%) patients and 11 (8%) control subjects (Tab. II).

Crystals were detected in 9 patients (6.5%) and 7 (5.1%)

of the control subjects (Tab. II). RBC cast, WBC cast, waxy

and broad casts were not found in either patients or control

subjects. Significant proteinuria (1+) was found in 11 (8%)

of the patients with 8 (5.8%) and 3 (2.2%) of them having

1+ and 2+, respectively (Tab. III). In the control group, only

2 (1.45%) had significant proteinuria. Significant hematuria

1+) was present in 9 (6.5%) of the patients with 7 (5.1%)

and 2 (1.45%) of them having 1+ and 2+, respectively, while

only 3 (2.2%) of the controls had significant hematuria. Ta-

ble IV shows the proportion of subjects with significant dip-

stick findings as compared with microscopic findings. All

the 9 patients with dipstick hematuria had proteinuria and

all the 11 patients with dipstick proteinuria had significant

microscopic hematuria. Ten patients out of the twenty-one

(47.6%) that had significant microscopic hematuria were

not detected by dipstick urinalysis. Similarly, the 2 controls

that had significant proteinuria also had hematuria and the

3 controls that had hematuria also had microscopic hema-

turia. Two control subjects who had significant microscopic

hematuria were not detected by dipstick urinalysis.

TABLE II

URINARY SEDIMENT CASTS AND CRYSTALS AMONG PATIENTS AND CONTROLS

Parameters (per hpf) Patients Controls P value

n (%) n (%)

Hyaline cast: Nil 130 (94.2) 127 (92) 0.4757

1-2 8 (5.8) 11 (8) 0.4757

> 2 - - -

Granular cast: Nil 136 (98.6) 138 (100) -

1-2 2 (1.4) - -

> 2 - - -

Crystals Nil 129 (93.5) 131 (94.9) 0.6064

1-2 9 (6.5) 7 (5.1) 0.6064 > 2 - - -

Red blood cell and White blood cell casts were nil.

hpf = high power field.

TABLE III

DIPSTICK URINALYSIS FINDINGS IN PATIENTS AND CONTROLS

Patients Controls P value

n (%) n (%)

Protein Nil 127 (92) 13 (98.65) 0.0106

1+ 8 (5.8) 2 (1.45) 0.0106

2+ 3 (2.2) - -

3+ - - -

Blood Nil 129 (93.5) 135 (97.8) 0.0766

1+ 7 (5.10) 3 (2.2) 0.0766

2+ 2 (1.45) - -

3+ - - -


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DISCUSSION

The pattern of urinary sediment in newly diagnosed,

adult Nigerian hypertensive patients was found to be mi-

croscopic hematuria in 34.8%, out of which 15.2% was

significant in spite of moderately elevated blood pres-

sure; leukocyturia in 7.2%, of which none was present in

significant quantity (Figs. 1 and 2). Other findings were

granular casts in 1.4%, hyaline casts in 5.8% and crystals

in 6.5% of patients, all of which were present in normal

quantities (Tab. II). When these parameters were com-

pared with the control group, only the microscopic he-

maturia showed a statistically significant difference. This

suggests that the urinary sediment manifestation of early

hypertensive renal damage is microscopic hematuria. In a

similar study by Ratto et al (29), the prevalence of urinary

sediment alterations in their patient population at baseline

was 12.2% (leukocyturia 6.6% and microhematuria with

or without leukocyturia 5.6%). The prevalence of micro-

hematuria of 15.2% in our patients is significantly higher

than the approximately 5.6% obtained in their study. This

wide difference may be related to the racial difference of

the study populations. While our study was conducted in

a predominantly Black population, the study by Ratto et al

was carried out among Caucasians. Blacks are known to

have a high prevalence of hypertensive renal damage and

they experience more rapid progression to ESRD. For ex-

ample, the gender- and age-adjusted incidence of ESRD

due to hypertension in Blacks is 8 times the rate among

the Caucasians (30). Furthermore, it has been shown that

hypertension at any level exacts a greater degree of car-

diovascular and renal damage in Blacks than Whites and

these target- organ complications occur much earlier in

life among Blacks (31). The Ratto et al study found that

the microhematuria in some of their patients was due to

TABLE IV

PROPORTION OF SUBJECTS WITH SIGNIFICANT DIPSTICK FINDINGS AND MICROSCOPIC HEMATURIA

Patients Controls p value

n (%) n (%)

Dipstick proteinuria 11 (8) 2 (1.45) 0.0106

Dipstick hematuria 9 (6.5) 3 (2.2) 0.7656

Microscopic hematuria 21 (15.2) 5 (3.6) 0.0010

renal diseases such as nephrosclerosis, interstitial dis-

ease, glomerulonephritis, etc. but the relative proportion

of these underlying diseases was not documented. The

prevalence of leukocyturia of 7.2% in our patients is com-

parable to the findings of Ratto et al (6.6%). Also impor-

tant is the fact that the leukocyturia in our patients was

present in an insignificant quantity and so it is difficult to

ascribe it to an underlying renal disease, although Ratto

et al ascribed leukocyturia in some of their female patients

to urinary tract infection. Granular casts and crystals were

present more in the study subjects while hyaline casts

were more present in the control group. However, the dif-

ference was not statistically significant, hence, possible

primary glomerular disease could not be ascribed to the

elevated blood pressure in the study subjects. The pres-

ence of granular casts is suspicious in the 2 patients in

whom they were found, although they were present in

normal quantities. A follow-up of these patients will be

necessary to determine their relevance in the long term,

since although casts and crystals were not analyzed by

Ratto et al, their study showed an increased prevalence

of microhematuria (5.6% to 7.4%) and leukocyturia (6.6%

to 17%) after a 6.6-year follow-up of their patients. Red

blood cell, white blood cell and epithelial cell casts were

not detected in our patients or the control subjects. This is

not so surprising, because they are almost always present

in active renal disease in most cases such as proliferate or

acute glomerulonephritis, urinary tract infections or acute

renal tubular disease which had already been excluded in

our patient population as confounding factors.

The prevalence of abnormal urinary sediment in newly di-

agnosed hypertensive Nigerians was therefore found to be

15.2%, essentially consisting of microhematuria. This fig-

ure is substantially higher than the 3.6% found among the

normotensive controls. Although the authors are not aware

of any similar studies previously carried out in this group


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of patients in our environment to compare this prevalence

rate, this value is rather high. The high prevalence rate

shows that a significant number of Nigerian hypertensive

patients already have subtle renal damage at the point of

diagnosis, even though the other markers of renal dam-

age such as serum creatinine and urea may still be within

the normal limits. Moreover, a more sensitive marker of hy-

pertensive renal damage such as microalbuminuria would

probably detect a much higher number of these patients

if this test was used. Indeed Olatunde et al (32) found the

prevalence of microalbuminuria in their hypertensive pa-

tients to be 17.4% despite the fact that 70% of the patients

were already on antihypertensive drugs. The prevalence of

microhematuria and microalbuminuria in hypertensive pa-

tients are comparable perhaps because the mechanisms

of their formation are almost similar, involving injury to the

glomerular endothelium, although microhematuria requires

greater and more intense injury and structural alterations.

Routine screening of newly diagnosed hypertensive pa-

tients for microalbuminuria would be rather costly for the

majority of our patients in the developing world who are

poor. The ISH-WHO of 1999 and the JNC guidelines for

the management of hypertension have advocated routine

urinalysis (both dipstick and microscopy) in the initial eval-

uation of hypertensive patients so that renal damage can

be detected early. The findings in this study suggest that

a urinary microscopic could be a valuable screening tool

not only for hypertensive renal damage but for renal condi-

tions that have potential for renal vascular injury. Dipstick

proteinuria was detected in 8% of the patients and 1.45%

of controls. Although the prevalence rate among patients

in this study was rather lower than the figure obtained by

Kannel et al (18%) (33), Bulpitt et al (16%) (34)and Ljung-

man et al (17%) (35), it is comparable to the findings of

Wollf et al (10%) (36) and Samuelsson et al (6%) (37) but

higher than the report by Lewin et al (4%) (38). A recent

general population screening to detect renal disease in

Germany reported a prevalence of persistent proteinuria of

12% (104 of 856 participants with self-reported dipstick-

positive proteinuria were confirmed by family physicians)

and 45% of these have essential hypertension (39). The

much higher prevalence observed in this study compared

to ours may be due to differences in the study methodolo-

gy and sensitivity of the test strips used to detect proteinu-

ria. The majority of previous studies on dipstick proteinuria

in Nigeria were done mainly on children and adolescents

(22-26).While Ajasin (23) found the prevalence of isolated

proteinuria among primary school children to be 8.6%,

Akinkugbe FM et al (24) and Asani et al (26) obtained prev-

alences of 5.4% and 1.95%, respectively, using similar cri-

teria. Among the adolescents, Akinkugbe (22)reported a

prevalence of 3.2% while Oviasu (25) obtained 4.7% with

similar age ranges of 12 to 22 years and 13 to 20 years,

respectively. These studies showed that the prevalence

of proteinuria among the young age groups varies signifi-

cantly, probably influenced by the geographical location.

However, there seems to be a reduced prevalence among

the older children. This observation cannot be applied to

adulthood, in which there is higher predisposition to re-

nal damage from various conditions such as hypertension.

Dipstick hematuria was found in 9 (6.5%) patients and in

only 3 (2.2%) of the control group in this study but the

difference is not statistically significant (p=0.0766). In his

study on adolescent students, Oviasu found a prevalence

of 0.55%. It is however difficult to compare these groups

because of the difference in the population characteris-

tics. All the patients and controls with dipstick hematuria

had proteinuria. The 21 (15.2%) patients that had micro-

scopic hematuria were inclusive of the 11 (8%) that had

dipstick proteinuria. This implies that about 47.6% of pa-

tients with abnormal urinary sediment were not detected

by the dipstick method. Similarly, 2 out of the 5 controls

with microscopic hematuria were not picked out by the

dipstick test. This high false- negative rate with dipstick

urinalysis is higher than the 6.5% to 36% obtained in the

literature (40-43). The difference might be due to the char-

acteristics of the population of the patients studied. While

this study focused on hypertensive patients, the majority

of the other study populations were unselected cohorts.

These high false- negative rates show that the sensitivity

of dipstick test in detecting microscopic hematuria in adult

hypertensive patients is poor.There has been a protract-

ed debate on the usefulness of urinary microscopy com-

pared with dipstick urinalysis in screening for diagnosis

of asymptomatic disease. While some authors are of the

opinion that microscopic examination of urinary sediment

should be limited to those patients with abnormalities in

the dipstick test, others strongly recommend its use as an

initial evaluation of patients to forestall the high false-pos-

itive and false-negative rates associated with the dipstick

method which have been discussed earlier. Our findings

in this study support the opinion that microscopy of the

urine should be part of the initial evaluation of not only

systemic hypertension but also other patients at a high risk

for kidney damage. There was a significantly lower value

of GFR in the patients than in the control subjects, which

is in agreement with the higher serum creatinine in these

patients. This suggests that renal function in hypertensive

patients is depressed compared with normotensive con-

trols. In conclusion, significant proportions of newly di-


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agnosed hypertensive Nigerians have sub-clinical kidney

damage, as evidenced by microscopic hematuria. There

is a high false-negative rate with dipstick urinalysis among

this patient population, which underscores the need for a

routine examination of urinary sediment in addition to a

dipstick test in the assessment of hypertensive patients. It

is recommended, however, that supravital stains should be

used for sediment identification in the absence of a phase

contrast microscope.

Financial support: No financial support.

Conflict of interest statement: None declared.

Address for correspondence:

Timothy O. Olanrewaju, MD

Division of Nephrology

Department of Medicine

University of Ilorin Teaching Hospital

PMB 1459, Ilorin, Nigeria

[email protected]

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Received: July 25, 2009

Revised: October 19, 2009

Accepted: October 20, 2009

Pattern of Urinary Sediments and Comparison

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