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VOLUME 13 NUMBER 1 • JULY 2016
RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
lipoprotein cholesterol (HDL-C) level for men < 1.04 mmol/l, fasting
plasma HDL-C for women < 1.29 mmol/l, blood pressure ≥ 130/85
mmHg and waist circumference for men > 102 cm and for women
> 88 cm.
17
This was a cross sectional study; 140 newly diagnosed non-
diabetic hypertensive subjects and 70 normotensive controls were
recruited consecutively from the cardiology clinic of LAUTECH
Teaching Hospital, Osogbo, Nigeria. The control subjects were
patients’ relatives and hospital staff who voluntarily gave their
consent to participate in the study. The hypertensive subjects and
controls were well matched in age and gender distribution.
Hypertension was diagnosed as systolic blood pressure of ≥
140 mmHg and/or diastolic blood pressure ≥ 90 mmHg taken
twice after at least five minutes of rest at the clinic, according to
standardised criteria. Subjects with mild hypertension were asked to
return after two weeks for confirmation. Those with moderate and
severe hypertension (JNC 7 stage 2) were recruited for the study
immediately. Patients with chronic kidney disease, known diabetics,
clinical evidence suggestive of CHD and pregnant patients were
excluded from the study.
Clinical and demographic data were taken using a structured
data form. Laboratory analyses performed included fasting plasma
glucose concentrations, urinalysis, ultrasound, and fasting serum
plasma lipid, electrolyte, urea and creatinine levels. All subjects had
12-lead resting electrocardiography.
Patients and controls were recruited after an informed consent.
Ethical approval was obtained for the study from the ethics board
of LAUTECH Teaching Hospital, Osogbo, Nigeria.
Statistical analysis
Statistical analyses were performed using the Statistical Package
for Social Sciences 16.0. Quantitative variables are summarised as
means ± standard deviation while qualitative data are summarised
using proportions and percentages. Inter-group comparison was
done using the
t
-test and chi-squared test as appropriate;
p
< 0.05
was taken as statistically significant.
Results
One hundred and forty hypertensive subjects and 70 controls were
recruited for this study. The mean age of the patients and controls
Table 1.
Clinical and demographic parameters of the study participants
Hypertensives Controls
Parameters (
n
= 140) (
n
= 70)
p
-value
Age (years)
55.14 ± 10.83
54.67 ± 10.89
> 0.05
#
Female gender,
n
(%) 75 (53.6)
37(52.9)
> 0.05
#
Family history of DM
5
7
> 0.05
Mean WC (cm)
Male
92.5 ± 13.4
84.0 ± 7.3
< 0.005*
Female
94.3 ± 11.5
84.6 ± 10.7
< 0.005*
Mean HC (cm)
100.15 ± 11.63
92.79 ± 9.92
> 0.05
Mean WHR
0.94 ± 0.082
0.91 ± 0.054
> 0.05
Mean BMI (kg/m
2
)
26.89 ± 5.31
23.86 ± 3.46
> 0.05
Mean SBP (mmHg)
147.18 ± 26.47
115.06 ± 13.11 < 0.005*
Mean DBP (mmHg)
89.25 ± 17.04
70.96 ± 9.67
< 0.005*
Mean PP (mmHg)
57.93 ± 24.38
44.75 ± 10.25
< 0.005*
DM, diabetes mellitus; WC, waist circumference; HC, hip circumference;
WHR, waist–hip ratio; BMI, body mass index; SBP, systolic blood pressure; DBP,
diastolic blood pressure; PP, pulse pressure. *Statistically significant.
Table 2.
Biochemical parameters of the study population
Hypertensives Controls
Parameter (
n
= 140) (
n
= 70)
p
-value
Mean sodium (mmol/l)
135.9± 4.7
133.7 ± 2.4
> 0.05
Mean potassium (mmol/l) 3.8 ± 0.5
3.1 ± 0.4
< 0.05*
Mean urea (mmol/l)
5.8 ± 2.2
3.2 ± 1.7
> 0.05
Mean creatinine (μmol/l)
84.2 ± 12.6
68.4 ± 10.8
> 0.05
Mean FBS (mmol/l)
5.6 ± 1.9
4.0 ± 1.3
< 0.005*
Mean LDL-C (mmol/l)
2.49 ± 1.41
2.35 ± 0.63
> 0.05
Mean HDL-C (mmol/l)
1.06 ± 0.36
1.29 ± 0.46
< 0.05*
Mean TG (mmol/l)
1.33 ± 0.59
1.18 ± 0.41
> 0.05
Mean TC (mmol/l)
4.84 ± 1.69
4.23 ± 1.29
> 0.05
FBS, fasting blood sugar; LDL-C, low-density lipoprotein cholesterol; HDL-C,
high-density lipoprotein cholesterol; TG, triglycerides; TC, total cholesterol.
*Statistically significant.
were 55.14 ± 10.83 years (age range 23–82 years) and 54.67 ±
10.89 years (age range 35–75 years), respectively. There was no
statistically significant difference between the mean ages of the
subjects and controls (
p
> 0.05).
The demographic and clinical parameters of the study participants
are as shown in Table 1. When compared with control subjects, the
hypertensive subjects had a higher mean systolic blood pressure
(147.18 ± 26.47 vs 115.06 ± 13.11 mmHg,
p
< 0.005), diastolic
blood pressure (89.25 ± 17.04 vs 70.96 ± 9.67 mmHg,
p
< 0.005),
pulse pressure (57.93 ± 24.38 vs 44.75 ± 10.25 mmHg) and fasting
plasma glucose level (5.6 ± 1.9 vs 4.0 ± 1.3 mmol/l,
p
< 0.005),
although the mean fasting plasma glucose levels were both within
normal limits. Also, the waist circumference of the hypertensive
subjects was significantly higher compared with the controls (93.89
± 11.96 vs 83.82 ± 9.0 cm,
p
< 0.05).
Table 2 shows the biochemical profile of the study population.
The hypertensive subjects had significantly higher mean fasting
plasma glucose levels (5.6 ± 1.9 vs 4.0 ± 1.3 mmol/l,
p
< 0.05).
The lipid profile analysis of the study population is also as shown
in Table 2. Hypertensive subjects had a significantly lower HDL-C
compared to control subjects (1.06 ± 0.36 vs 1.29 ± 0.46 mmol/l,
p
< 0.05). Although mean total cholesterol, low-density lipoprotein
cholesterol (LDL-C) and triglyceride levels were higher among the
hypertensive subjects than the controls, they were not statistically
significantly different.
Hypertensive subjects with the metabolic syndrome were older
and were more likely to be female than those without the metabolic
syndrome. They also had a higher body mass index, systolic blood
pressure, fasting plasma glucose level and increased prevalence of
left ventricular hypertrophy, as shown in Table 3.
As seen in Table 4, hypertension combined with obesity and
low HDL-C level was the commonest pattern of combination
of cardiovascular risk factors among the hypertensive subjects,
followed by a combination of hypertension, obesity and impaired
glucose tolerance.
Discussion
The frequency of occurrence of the metabolic syndrome in this
study was 31.4% in the hypertensive subjects compared to 15.7%
in the control group. A similar report by Okpechi
et al
.
18
among
black hypertensives in South Africa documented a frequency of
occurrence of 33.5%. Therefore, about a third of newly diagnosed