RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
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, those with clinical evidence suggestive of coronary heart disease 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, urinalysis, ultrasound, fasting serum plasma lipids, electrolytes, urea and creatinine. 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 analyses were performed using the Statistical Package for Social Sciences 16.0. Quantitative variables were summarised as means ± standard deviation while qualitative data were summarised using proportions and percentages. Intergroup comparison was done using the t-test and chi square 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 the controls was 55.14 ± 10.83 years (range 23–82) and 54.67 ± 10.89 years (range 35–75), respectively. There was no statistically significant difference between the mean ages of the subjects and Table 1. Clinical and demographic parameters of study participants
Parameters
Hypertensive subjects (n = 140)
Control subjects (n = 70)
Age (years)
55.14 ± 10.83
54.67 ± 10.89
> 0.05
75 (53.6)
37 (52.9)
> 0.05
5
7
> 0.05
Male
92.5 ± 13.4
84.0 ± 7.3
< 0.005*
Female
94.3 ± 11.5
84.6 ± 10.7
100.15 ± 11.63
92.79 ± 9.92
Family history of diabetes mellitus
0.94 ± 0.082
Mean WHR
0.91 ± 0.054
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
Table 2. Biochemical parameters of the study population
Parameter
Hypertensive subjects (n = 140)
Mean sodium (mmol/l)
Control subjects (n = 70)
p-value
135.9 ± 4.7
133.7 ± 2.4
Mean potassium (mmol/l)
3.8 ± 0.5
3.1 ± 0.4
< 0.05*
< 0.005*
Mean urea (mmol/l)
5.8 ± 2.2
3.2 ± 1.7
> 0.05
> 0.05
Mean creatinine (μmol/l)
84.2 ± 12.6
68.4 ± 10.8
> 0.05
> 0.05
Mean FBS (mmol/l)
5.6 ± 1.9
4.0 ± 1.3
Mean WC (cm)
Mean HC (cm)
Discussion
p-value
Gender Female (%)
controls (p > 0.05). The demographic and clinical parameters of the study participants are 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 (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 than 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 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 hypertensive subjects than controls, they were not statistically significant. Hypertensive subjects with the metabolic syndrome were older and were more likely to be female than those without the MS. 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. Table 4 shows that hypertension combined with obesity and low HDL-C was the commonest pattern of combination of cardiovascular risk factors among hypertensive subjects, followed by a combination of hypertension, obesity and impaired glucose tolerance.
> 0.05
< 0.005*
Mean BMI (kg/m )
26.89 ± 5.31
23.86 ± 3.46
> 0.05
Mean LDL-C (mmol/l)
2.49 ± 1.41
2.35 ± 0.63
> 0.05
Mean SBP (mmHg)
147.18 ± 26.47
115.06 ± 13.11
< 0.005*
Mean HDL-C (mmol/l)
1.06 ± 0.36
1.29 ± 0.46
< 0.05*
Mean DBP (mmHg)
89.25 ± 17.04
70.96 ± 9.67
< 0.005*
Mean TG (mmol/l)
1.33 ± 0.59
1.18 ± 0.41
> 0.05
Mean PP (mmHg)
57.93 ± 24.38
44.75 ± 10.25
< 0.005*
Mean TC (mmol/l)
4.84 ± 1.69
4.23 ± 1.29
> 0.05
2
WHR: waist–hip ratio, BMI: body mass index, SBP: systolic blood pressure, DBP: diastolic blood pressure, PP: pulse pressure, HC: hip circumference. * Statistically significant.
108
FBS: fasting blood sugar; LDL-C: low-density lipoprotein cholesterol; HDL-C: high-density lipoprotein cholesterol; TG: triglycerides; TC: total cholesterol. * Statistically significant.
VOLUME 7 NUMBER 3 • SEPTEMBER 2010