7 / 52
SA JOURNAL OF DIABETES & VASCULAR DISEASE
RESEARCH ARTICLE
VOLUME 13 NUMBER 2 • DECEMBER 2016
57
(ACS), congestive heart failure (CHF, NYHA class II or greater),
valvular heart disease, cerebral infarction or transient ischaemic
attack (TIA).
Self-reported physical activity, alcohol use and smoking
habits, known duration of diabetes mellitus, current treatments
and measures of adiposity [body mass index (BMI) and waist
circumference] were obtained in all patients. Overweight and obesity
were classified as BMI ≥ 25 kg/m
2
and ≥ 30 kg/m
2
, respectively.
Central obesity was categorised as waist circumference > 102 cm
in men and > 88 cm in women.
Blood pressure (BP) was measured in the supine position using a
mercury sphygmomanometer with an appropriate cuff on the left
arm; the average of two readings was used for statistical analysis.
Pulse pressure (PP) calculated as systolic blood pressure (SBP) minus
diastolic blood pressure (DBP) was considered increased when >
60 mmHg.
8
Hypertension was defined as BP > 140/90 mmHg or
currently on antihypertensive treatment. Heart rate was counted
over a full minute.
A 12-hour overnight fasting venous blood sample was collected
for measurement of total cholesterol and its sub-fractions [low-
density lipoprotein cholesterol (LDL-C) high-density lipoprotein
cholesterol (HDL-C)], triglycerides (TG), plasma glucose, serum
uric acid and creatinine levels. LDL-C was calculated according to
the Friedewald formula.
9
Dyslipidaemia was an LDL-C level ≥ 2.6
mmol/l or HDL-C < 1.03 mmol/l or TG > 1.69 mmol/l.
According to the NCEP-ATP III guidelines,
10
the metabolic
syndrome (MS) was, in addition to diabetes, the presence of
two of the followings risk factors: BP > 130/85 mmHg or current
antihypertensive treatment, central obesity as defined above,
HDL-C < 1.03 mmol/l and/or TG > 1.69 mmol/l.
We computed glomerular filtration rate [creatinine clearance
(CrCl)] using the MDRD equation.
11
Chronic kidney disease (CKD)
was a CrCl rate < 60 ml/min per 1.73 m
2
; it was stratified into mild
(CrCl > 60 ml/min per 1.73 m
2
), moderate (CrCl: 30–60 ml/min
per 1.73 m
2
) and severe (CrCl < 30 ml/min per 1.73 m
2
).
12
A uric
acid level > 416 μmol/l defined hyperuricaemia. Proteinuria was a
24-hour urine protein excretion rate > 0.3 g.
Echocardiographic examination was performed with the patient
in the partial left lateral decubitus position using an Acuson
128XP/10˝ machine with a 3.5-MHz transducer. Two-dimensional
guided M-mode measurements were obtained as recommended by
the American Society of Echocardiography (ASE).
13
We used the Devereux modified cubed formula to calculate
left ventricular mass (LVM).
14
To account for gender and body size
variations, LVM was indexed to height
2
.
7
, with a boundary of 51 g/
m
2
.
7
to define LVH in both genders.
15
Relative wall thickness (RWT)
was calculated as 2 × PWTD (posterior wall thickness, diastolic)/
LVIDD (left ventricular internal diameter, diastolic). It was considered
increased when > 0.45.
16
RWT and left ventricular mass index (LVMI)
were used to characterise LV geometry as normal (normal LVMI and
normal RWT), concentric remodelling (normal LVMI and increased
RWT), concentric hypertrophy (increased LVMI and increased RWT)
and eccentric hypertrophy (increased LVMI and normal RWT). LV
ejection fraction (LVEF) was calculated using Tiechloz’s formula.
17
Statistical analysis
Data are expressed as mean ± standard deviation (SD) or relative
frequency in per cent. The distribution of duration of hypertension
and triglyceride levels being positively skewed, the non-parametric
Mann–Whitney test was used for these variables. Chi-square and
Student
t
-tests were used for comparing categorical and normally
distributed continuous variables, respectively.
Multiple regression models and the likelihood ratio method were
performed with LVH as the dependent variable for the assessment
of the strength and independence of association with risk factors.
Adjusted odds ratio (aOR) were calculated for each variable from a
model which included all these variables; the resulting aOR allowed
the direct comparison of the independent effects of these variables
to decide which variable has the greater effect on LVH. All statistical
analyses were performed with SPSS for Windows, version 18.0. A
p
-value ≤ 0.5 was considered statistically significant.
Table 1.
Clinical characteristics of the whole group and diabetics with
and without CKD.
Normal renal
Whole group function
CKD
Characteristic
(
n
= 60)
(
n
= 70)
(
n
= 32)
Gender:
M/F 23/37
11/17
12/20
Age (years)
58 ± 8
59 ± 8
58 ± 8
Duration DM (years)
11 ± 8
8 ± 6
13 ± 8***
Central obesity (%)
62
32
30
AHT (%)
80
37
43
MS (%)
58
28
30
Antidiabetic drugs (%)
97
45
52
Antihypertensive drugs (%)
67
25
42**
Smoking (%)
10
7
3
BMI (kg/m
2
)
26 ± 5
27 ± 6
26 ± 5
Waist (cm)
95 ± 12
96 ± 13
95 ± 12
SBP (mmHg)
148 ± 26
148 ± 29
149 ± 23
DBP (mmHg)
84 ± 13
86 ± 15
82 ± 11
PP (mmHg)
64 ± 21
61 ± 23
67 ± 19
Heart rate (beats/min)
83 ± 15
83 ± 20
86 ± 12
Data are expressed as mean ± SD or relative frequency in per cent.
CKD, chronic kidney disease; M, male; F, female; DM, diabetes mellitus;
AHT, arterial hypertension; MS, metabolic syndrome; BMI, body mass
index; SBP, systolic blood pressure; DBP, diastolic blood pressure; PP,
pulse pressure.
*
p
≤ 0.05; **
p
≤ 0.01; ***
p
≤ 0.001in comparison with normal renal
function.
Table 2.
Biological characteristics of the patients and data according to
renal function.
Normal renal
Whole group function
CKD
Characteristic
(
n
= 60)
(
n
= 28)
(
n
= 32)
TC (mmol/l)
5.61 ± 1.62
5.74 ± 1.40
5.62 ± 1.71
LDL-C (mmol/l)
3.80 ± 1.54
3.90 ± 1.42
3.73 ± 0.78
HDL-C (mmol/l)
1.45 ± 0.67
1.44 ± 0.51
1.53 ± 0.84
TG (mmol/l)
1.60 ± 1.30
1.84 ± 1.80
1.33 ± 0.78
Glucose (mmol/l)
8.10 ± 3.31
8.27 ± 2.77
7.80 ± 3.80
Uric acid (μmol/l)
410 ± 178
309 ± 107
500 ± 166***
CrCl (ml/min/173 m
2
)
64 ± 41
97 ± 35
35 ± 18
24-h proteinuria (g)
0.79 ± 1.72
0.07 ± 0.164
1,42 ± 2,17
Data are expressed as mean ± SD
CKD, chronic kidney disease; TC, total cholesterol; LDL-C, low-density
lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; TG,
triglycerides; CrCl, creatinine clearance.
*
p
≤ 0.05; **
p
≤ 0.01; ***
p
≤ 0.001 in comparison with normal renal
function.