Prevalence of Hypertension and Impaired Renal Function in Diabetic Patients Attending Ahmadu Bello University Teaching Hospital (Abuth), Shika, Zaria, Kaduna State, Nigeria
To determine the prevalence of hypertension and impaired renal function in diabetic patients attending Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State, Nigeria. Two hundred subjects (one hundred and twenty diabetic and eighty control subjects) attending the diabetic clinic of the hospital were evaluated between the months of May and June, 2012. From the results, the prevalence of hypertension among diabetic patients attending the hospital was 78.33%. A total of 63.33% of the patients have type II diabetes mellitus, while 36.67% had type I. The urea, potassium, bicarbonate and glucose levels were normal and creatinine (58.33%) and sodium (88.1%) levels were abnormal in most patients. The result shows that 80% of female patients between 50 to 59 years were hypertensive, while 40% of the males within the same age range were also hypertensive. Also, 30% of unemployed diabetic patients attending the hospital were hypertensive, while none of the control subjects were hypertensive. Most of the diabetic patients (40%) were primary school certificate holders, while 2.5% of the patients had a post graduate degree. In conclusion, the high prevalence of hypertension and renal impairment are public health challenges and so educational programs on monitoring of blood sugar and screening of risk factors for hypertension, early diagnosis and treatment of hypertension should be given periodically.
to cite this article:
M.A. Abdulazeez, A.I. Busari, S. Yakubu, K.M. Anigo, H.O. Idris and A. Salihu, 2013. Prevalence of Hypertension and Impaired Renal Function in Diabetic Patients Attending Ahmadu Bello University Teaching Hospital (Abuth), Shika, Zaria, Kaduna State, Nigeria. Journal of Medical Sciences, 13: 346-352.
Received: March 29, 2013;
Accepted: April 22, 2013;
Published: June 13, 2013
The elevation of systolic blood pressure 140 mm Hg and diastolic pressure 90
mm Hg is termed hypertension (WHO, 2008). Previous studies
have attributed the co-existence of hypertension and diabetes in affected individuals
to similarities in genetic and environmental factors of both diseases. Also,
it has been reported that people with hypertension are more likely to develop
type II diabetes than those without hypertension (The National
High Blood Pressure Education Program Working Group, 1994. Similarly hypertension
is twice as prevalent in diabetic as in non-diabetic individuals (Simonson,
1988). Furthermore, it has been clearly shown that hypertension in diabetic
patients is associated with accelerated progression of both microvascular (retinopathy
and nephropathy) and macrovascular (atherosclerotic) complications (Grundy
et al., 1999). These complications are increased by the co-existence
of hypertension (Epstein and Sowers, 1992).
Diabetes Mellitus is defined by World Health Organization on the basis of the
laboratory finding as fasting venous plasma glucose concentration more than
or equal to 7.0 mmol L-1 or a random venous plasma glucose concentration
more than or equal to 11.1 mmol L-1. It can also be defined as a
clinical syndrome characterized by hyperglycaemia due to absolute or relative
deficiency of insulin (Grundy et al., 1999).
The risk of coronary heart disease in diabetic patients with hypertension has
generated interest in studying the relationship between the two conditions (Garcia
et al., 1974). Obesity and other risk factors such as smoking, alcohol
consumption, diet and lack of physical activities predispose individuals to
these diseases hence life style modification by affected individual becomes
The prevalence of diabetes and hypertension has been reported to be on the
increase, with a projected rise of 366 million diabetics in 2030 compared to
the 171 million in 2000 and a 60% rise in people with hypertension by 2025.
Presently, about 60% of Nigerian diabetics are hypertensive (WHO,
2008). The high cost of antihypertensive drugs makes most patients non compliant,
making blood pressure control unsatisfactory and their reno-protective benefits
missed. Thus, there is a need to investigate the prevalence of impaired renal
function in diabetic patients and to determine the current prevalence of high
blood pressure in patients with diabetes in order to enlighten the populace
about the effects and risks associated with the disease. This study therefore,
aims at determining the prevalence of hypertension and impaired renal function
in diabetic patients attending Ahmadu Bello University Teaching Hospital, Zaria,
Kaduna State, Nigeria and the effects of some risk factors on their physical
MATERIALS AND METHODS
A total of Two hundred samples were allocated for the research. Samples were
obtained from one hundred and twenty diabetics (sixty-two males and fifty-eight
females) and eighty control subjects (comprising thirty-four males and forty-six
females) attending the diabetes clinic of Ahmadu Bello University Teaching Hospital
(ABUTH) Zaria, Kaduna State, Nigeria. Ethical approval was obtained from the
ethics committee of Ahmadu Bello University Teaching Hospital (ABUTH) Zaria
before commencement of the experiment.
Inclusion criteria and exclusion criteria: Patients studied had been
diagnosed as having diabetes mellitus using the WHO (1999)
criteria with FBG 7.0 mmol L-1 (126 mg dL-1) and 2 h post
prandial glucose 11.1 mmol L-1 (200 mg dL-1), attending
ABUTH, Zaria and within the age of 20-70 years. Only those who consented were
included in the study. Healthy patients attending the hospital for routine check-up
were selected as control. Individuals below 20 years and those who refused to
give their consent were excluded.
Blood collection and sampling: Five milliliters of venous blood was
aseptically collected from all subjects, after 12 h fasting into well-labelled
test-tubes. The samples were allowed to clot at room temperature, serum obtained
and stored at-20°C until assay period.
Administration of questionnaires: A questionnaire was administered to
obtain information about the age, sex, type of diabetes, weight, lifestyle associated
with diabetes and hypertension; as well as demographic characteristics.
Analysis of blood samples
Estimation of blood glucose: Serum blood glucose was measured by glucose
oxidase method (Trinder, 1969). Briefly, phenol reagent
(2 mL) was added into three test tubes labeled blank, test and standard. This
was followed by 50 μL distilled water, serum and standard added into the
blank, test, standard, respectively. Glucose colour reagent (2 mL) was then
added to all tubes. The contents were mixed, incubated at 37°C for 20 min
and absorbance was read at 510 nm.
Creatinine: Creatinine was estimated using the method of Jaffe in 1919.
Briefly, 3 test tubes were labeled test, standard and blank. About 1.5 mL of
distilled water and 0.5 mL each of 10% sodium tungstate and 2/3N sulphuric acid
were added to the test and blank. The contents were mixed and centrifuged for
10 min. The supernatants (1.5 mL) were transferred to new test tubes, while
1.5 mL standard solution was transferred into the standard tube. Picric acid
(0.5 mL) and 0.75 N sodium hydroxide (0.5 mL) were added to all test-tubes and
incubated for 15 mins at room temperature, before taking absorbance at 520 nm.
Determination of chloride: Chloride was estimated as described by Schales
and Schales (1971). Briefly, to 2 mL of deionized water, 200 mL of sample
and 2 drops of the indicator were added and mixed. This was titrated against
mercuric nitrate until a violet-blue coloured complex was observed.
Bicarbonate: Bicarbonate was estimated as described by Scribner
and Caillouette (1954). Into a universal glass bottle, 200 μL serum
and 100 μL of 0.01N HCl were added. This was followed by the addition of
500 μL of CO2 free water and a drop of phenol red indicator.
Titration was done using 0.01 N sodium hydroxide to a faint pink colour as the
end point. Concentration of bicarbonate was calculated thus: 1 Lx50 mEq L-1x1
Urea: This was determined using the diacetylmonoxime method. Three universal
glass bottles were labeled test, standard and blank. Into the test and standard
bottles, 10 mL of distilled water was added. Then, 100 μL of sample and
100 μL of standard solution was added with homogenous mixing into the test
and standard tubes, respectively. The supernatant (1000 μL) obtained from
both test-tubes was transferred into freshly labeled test tubes and 1000 μL
distilled water added; while 2000 μL of distilled water was added into
the test-tube labeled blank. A 2 mL volume of working reagent and mixed acid
reagent were sequentially added into the test-tubes and mixed thoroughly. All
test-tubes were then placed into a hot block at 100°C for 20 min, allowed
to cool and absorbance was read at 520 nm:
Determination of Na+ and K+: Sodium and Potassium
were estimated using flame photometric method.
Table 1 shows the percentage of male and female diabetic
and non-diabetic subjects in the study population. There were 62 (51.7%) male
and 58 (48.5%) female patients, while the control subjects were made up of 36
(42.5%) females and 46 (57.5%) males.
A total of 78.33% of diabetic patients were found to be hypertensive, while
21.67% were not hypertensive. Among the diabetic hypertensive patients, 36.66%
were females and 41.67% were males, while only 10% female and 11.67% male diabetics
were not hypertensive (Fig. 1).
Figure 2 shows that 63.33% of the diabetic patients attending
ABUTH have type II diabetes mellitus, while 36.33% have type I diabetes mellitus.
Among the patients with type II, 43.33% were hypertensive; while 33.33% of the
patients with type I were found to be hypertensive.
||Prevalence of hypertension in male and female diabetic patients
attending Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State,
||Prevalence of hypertension (based on the diabetes type) in
diabetic patients attending Ahmadu Bello University Teaching Hospital, Zaria,
Kaduna State, Nigeria
|| Percentage of male and female diabetic and non-diabetic subjects
||Prevalence of impaired renal function in diabetic patients
attending Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State,
||Prevalence of hypertension by age group and sex in diabetic
patients attending Ahmadu Bello University Teaching Hospital, Zaria, Kaduna
A large percentage of diabetic patients attending ABUTH had normal electrolyte
levels, with 60, 55.9, 67.8 and 62.7% having normal levels of urea, potassium
ion, bicarbonates and glucose, respectively. However, about 88.1% of the patients
had abnormal levels of sodium ion, while 58.33% had abnormal creatinine levels
With respect to the prevalence of hypertension in diabetic patients by age
group and sex; result from the study shows that 80% of female patients between
50 to 59 years were hypertensive, while 40% of the males within the same age
range were hypertensive (Fig. 4).
Analysis showed that a large percentage of diabetic patients (34.69%) attending
the hospital were unemployed; with 30% of them having high blood pressure, while
only 11.22% of patients in the control group were unemployed. Also, about 13.26%
of the diabetic patients were employed and 11.22% were retirees (Fig.
From the results, it was obvious that all participants achieved some level
of education with the following distributions: 40% of diabetic patients were
primary school certificate holders, 10% were JSCE and SSCE holders, 22.5% were
graduate degree holders and 2.5 had post-graduate degrees (Fig.
||Prevalence of hypertension by employment status in diabetic
patients attending Ahmadu Bello University Teaching Hospital, Zaria, Kaduna
||Educational status of diabetic patients and control subjects
attending Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State,
For all the respondents, 85.96% of diabetic patients have had their blood pressures
measured within twelve months, while only 14.04% of the control subjects measured
their blood pressure within the same period. Also, 82.1% of diabetic patients
were aware of their hypertensive status, 16.1% were not and 1.8% of them were
not sure of their hypertensive status. Although only 5.4 and 17.9% of the diabetic
patients were exposed to cigarette and indoor smoke, respectively; a large percentage
of diabetic patients (61.9%) and control subjects (84.6%) took non-steroidal
anti-inflammatory drugs, while only 7.7% of control subjects and 33.3% of the
patients were not taking non-steroidal anti-inflammatory drugs (Table
Several studies have demonstrated a very high prevalence of hypertension in
Sub-saharan Africa (Addo et al., 2007; Ulasi
et al., 2011).
|| Some characteristics of the study population
|All results above were expressed as percentages (%), except
BMI, expressed as kg m-2 of Mean±SEM
Report by Cooper et al. (1997), put the prevalence
of hypertension in Nigeria and Cameroun at 16%. The prevalence of hypertension
in people with diabetes mellitus is known to be variable worldwide, with data
from several epidemiologic studies suggesting that the prevalence of hypertension
in patients with diabetes mellitus is approximately 1.5-2.0 times greater than
in an appropriately matched non-diabetic population (Simonson,
1988). A study by Bugaje et al. (2005),
demonstrated a rapid increase in prevalence rate of hypertension in adolescents
in Zaria. It has also been reported that about 60% of Nigerian diabetics are
hypertensive, as found in many other areas of the world, with females having
a slightly higher incidence than males (Wingard and Barret-Connor,
1998). The prevalence of hypertension in diabetic patients attending Ahmadu
Bello University Teaching Hospital, Zaria was 78.33%, a result which agrees
with reports by Vukovich et al. (1992) and Tiptaradol
and Aekplakorn (2012) that hypertension affects 75% of diabetic patients.
It is thus possible that the high prevalence of hypertension in this study represents
the increasing prevalence across the globe. Several factors acting together,
such as metabolic abnormalities, elevated plasma levels of lipoprotein, oxidation
of low-density lipoprotein cholesterol and formation of glycated low-density
lipoprotein, as well as abnormalities in the structure and function of the vascular
endothelium are known to be responsible for the damage of the vasculature resulting
in cardiovascular diseases, including hypertension, in diabetic individuals
(Grossman and Messerli, 2008). In addition, the high
prevalence of hypertension among diabetic patients has been attributed to high
concentration of factor VIII in hyperglycemic conditions, known to accelerate
the rate of thrombin formation and contribute to occlusive vascular diseases
in diabetic patients (Carmassi et al., 1992).
The high percentage (63.33%) of type II compared to type I diabetic patients
attending ABUTH agrees with reports by Unadike et al.
(2011) that type II diabetic population is usually higher than type I. Also,
type II diabetes has been shown to occur in over 90% of diabetic patients; and
affects older adults, particularly those over 50 years of age (Carl
and Edward, 2001). The prevalence as observed in the present study may be
attributed to high BMI and sedentary lifestyle of the patients (Table
2). This finding is in agreement with that of Grossman
and Messerli (2008) who showed that as the prevalence of type II diabetes
increases with obesity, higher fat diets and decreased physical activity. With
BMI, the risk of obesity, a strong risk factor for the coexistence of diabetes
and hypertension is determined (Balogun and Salako, 2011).
It has been suggested that hyperinsulinemia and insulin resistance may also
contribute to the maintenance of an elevated blood pressure because insulin
promotes sodium retention and enhances sympathetic nervous system activity (Simonson,
1988). Therefore, the abnormally high levels of sodium ion in most (88.1%)
of the diabetic patients as observed in this study may cause accumulation of
extracellular fluid and expansion of plasma volume as a result of renal insufficiency,
resulting in increased blood pressure (Simonson, 1988).
Also, the abnormal level of creatinine, urea and other electrolytes in the diabetic
patients (Fig. 3) agrees with studies by Sweileh
et al. (2009) that 63.5% of diabetic patients have renal dysfunctions,
which may be caused by hyperglycemia and hemodynamic abnormalities of the renal
micro circulation that results in progressive structural and functional glomerular
The high prevalence in both male and female diabetic patients between the ages
of 50-59 years agrees with studies by American Diabetes
Association, 1997 that there is high prevalence of hypertension among females.
Also, studies have demonstrated that women have a lower prevalence of hypertension
than men before age 50, but after age 55, the prevalence increases. The reasons
for these differences are not clear, but hypertensive women have been shown
to have somewhat different hemodynamic findings from men (Pemu
and Offili, 2008). In another study, Didem et al.
(2008) attributed the high prevalence of hypertension in women to their
age being within the menopausal period and the protective effect of estrogen.
The large percentage of hypertensives among the unemployed diabetic patients
(30%) conforms with studies by Lucini et al. (2005)
stressing the significant role of psychosocial stressors in the development
of cardiovascular diseases, including hypertension. Studies have shown that
low occupational status and the threat or reality of unemployment increases
the risk of hypertension (Gallo et al., 2004).
From our results (Fig. 6), about 40% of diabetic patients
had only primary school certificates, while only 2.5% have post graduate degree.
This is compatible with the decreased prevalence associated with an increase
in education as reported by Sadeghi et al. (2004).
It is thus obvious that education, coupled with enlightenment could be related
to the protection of hypertension.
Hammoudeh et. al. (2006) and Lorenzo
et al. (2005) reported that the risk of hypertension is higher in
smokers than non-smokers. From our present study, although, the population of
patients smoking and those exposed to indoor smoke (Table 2)
was very low, it is possible that they could also be exposed to other risk factors
as data from the Nurses Health Study, suggests that maintaining a desirable
body weight, eating healthy diet, regular exercises, non-smoking and moderate
consumption of alcohol reduces the risk of hypertension by 84% (Lawrence
et al., 1996).
The high percentage of diabetic patients taking Non-Steroidal Anti-Inflammatory
Drugs (NSAIDs) may account for the high prevalence of hypertension within the
study population as NSAIDs has been shown to induce dose-related fluid retention
and raise blood pressure in some patients (Morgan et
al., 2000). It can also reduce renal blood flow and cause a dose-dependent
form of blood pressure salt sensitivity. Clinical trials have demonstrated that
NSAIDs may diminish the overall efficacy of certain antihypertensive medications
such as diuretics, β-blockers and angiotensin converting enzyme inhibitors
(Morgan et al., 2000).
In conclusion, this study has shown that the prevalence of hypertension among
diabetic patients attending ABUTH is 78.33%, with most patients presenting with
impaired renal function; and most are unaware of their hypertensive status.
This high prevalence is a public health challenge; hence, educational programs
need to be established with the aim of monitoring blood sugar, screening of
risk factors for hypertension, early diagnosis and treatment of hypertension.
At the same time, routine blood pressure measurement for the elderly people
should be encouraged. Public health awareness of simple measures, such as a
low salt diet, physical exercises and avoiding obesity to maintain normal arterial
blood pressure should also be encouraged.
The authors of this article are grateful to the staff and participants of the
Department of Chemical Pathology, Faculty of Medicine, Ahmadu Bello University
Teaching Hospital, Zaria.
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