Cardiovascular Journal of Africa: Vol 27 No 6 (November/December 2016)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 6, November/December 2016

362

AFRICA

Data were obtained using a standard questionnaire,

which collected information on age, gender, education level,

duration of hypertension, the number and class of drugs

taken for hypertension or other conditions, compliance with

antihypertensive drugs, family history of hypertension (FH-HT),

diabetes (FH-DM) or cardiovascular disease (CVD), smoking

and alcohol use, and physical activity.

A physical examination was performed on each patient

to measure height, weight, waist circumference (WC), blood

pressure and pulse rate. Height and weight were measured

with reference to recommended procedures. Body mass index

(BMI) was calculated as weight (kg)/height

(m). Overweight

and obesity were defined as BMI

25 and

30 kg/m².

Waist

circumference (WC) was taken to the nearest 1 cm, using a tape

measure. Central obesity was defined as WC

94 cm in men and

80 cm in women.

Seated blood pressure (BP) was measured using an electronic

device, OMRON M3 Intellisense (OMRON Health, Vietnam),

on the left arm at the level of the heart after five minutes’ rest.

BP was measured three times and the mean of the last two

readings was used for analysis. Pulse pressure (PP) was calculated

as systolic (SBP) minus diastolic blood pressure (DBP). Mean

arterial pressure (MAP) was DBP

PP divided by 3.

While on their usual diet, a venous blood sample was

taken from an antecubital vein for the determination of levels

of serum uric acid, cholesterol and its sub-fractions, and

triglycerides using enzymatic methods (Biomérieux France).

Low-density lipoprotein cholesterol (LDL-C) was calculated

using the Friedewald formula.

For estimated glomerular filtration rate (eGFR)

determinations, the abbreviated equation from the MDRD

study was used.

We calibrated the creatinine results measured

using the Jaffe method against a traceable isotope dilution mass

spectrometry (IDMS) enzymatic method (creatinine

, Roche

enzymatic diagnostics) as described elsewhere.

Recalibrated

serum creatinine values were thereafter computed for each

participant and the new MDRD study equation was used

for estimation of eGFR as 175

[serum creatinine level (mg/

dl)] – 1.154

[age (years)] – 0.203. For women and for blacks

(all patients in our study), the product of this equation was

multiplied by a correction factor of 0.742 and 1.21, respectively.

All analyses were performed at the National Laboratory of the

National AIDS Control Program.

Capillary blood glucose was determined using Accu-chek

Compact plus glucometer (Roche Diagnostica, Manheim,

Germany) with the glucose oxidase method. Reactive Dipstick

Condor Teco (Condor Teco Medical Technology Co, China)

was used to determine semi-quantitative proteinuria. A resting

electrocardiogram (ECG) was performed for each patient and

the Sokolow index was calculated. The 2007 European Society

of Hypertension/European Society of Cardiology (ESH/ESC)

guidelines

were used to evaluate global cardiovascular (CV) risk

in the study population.

Subjects were classified as having: controlled SBP and DBP

if current antihypertensive treatment was accompanied by clinic

SBP

140 mmHg and clinic DBP

90 mmHg; uncontrolled

SBP only if SBP was

≥

140 mmHg and DBP

90 mmHg;

uncontrolled DBP only if DBP was

≥

90 mmHg and SBP

140

mmHg; uncontrolled SBP and DBP if SBP and DBP were

≥

140

mmHg and

≥

90 mmHg, respectively.

The metabolic syndrome was defined according to

International Diabetes Federation criteria.

Diabetes was defined

as blood glucose level

≥

126 mg/dl (6.99 mmol/l) or current use

of antidiabetic drugs.

Excessive alcohol intake was defined by regular intake of two

or more glasses per day of beer or equivalent for at least one

year, knowing that one glass of beer contains 10 g of alcohol.

Smoking was defined as regular consumption of at least one

cigarette per day for more than five years or having stopped

smoking for less than five years.

Physical activity in leisure time was categorised as active

for subjects who exercised for at least four hours per week,

and inactive or sedentary for all the others.

Compliance

with therapy was defined as self-reported regular intake of

antihypertensive drugs.

ECG-determined left ventricular hypertrophy (ECG-LVH)

was defined as a Sokolow index

35 cm.

According to K/DOQI

guidelines,

chronic kidney disease (CKD) and renal failure (RF)

were defined as eGFR

90 and

60 ml/min/1.73 m², respectively.

According to the 2007 ESH/ESC guidelines,

moderate, high

and very high absolute CV risk were defined as 10–20, 20–30 and

≥

30% probability of a CV event in the next 10 years, respectively.

Proteinuria was defined as dipstick proteinuria

≥

The study was conducted in accordance with the principles of

the 18th World Assembly (Helsinki, 1964). The study protocol

was submitted to the ethics committee of Kinshasa School

of Public Health of the University of Kinshasa and received

clearance under the number ESP/CE/024/2012.

Statistical analysis

Data are expressed as mean

standard deviation (SD) or

relative frequency (%). Chi-squared and Student’s

-tests

were used to compare categorical and continuous variables,

respectively. Skewed continuous variables were compared using

the non-parametric Mann–Whitney test. Stepwise logistic

regression analysis was used to identify correlates of uncontrolled

hypertension; odds ratio (OR) and confidence interval (CI) were

obtained for each independent variable. To remain in the model a

factor had to reach a

-value

≤

0.05. All statistical analyses were

performed with SPSS version 20 for Windows at the Division of

Epidemiology and Biostatistics of Kinshasa School of Public

Health, University of Kinshasa.

Results

A total of 298 hypertensive patients, 208 women and 90 men,

were recruited in this study. Clinical characteristics of the study

population as a whole are given in Table 1. Their mean age was

10 years; they had on average a BMI of 26

5 kg/m², a WC

of 90

11 cm, a SBP of 151

24 mmHg and a DBP of 87

mmHg.

A family history of hypertension or diabetes was present in

50 and 31% of patients, respectively. In 67% of patients, the

duration of hypertension was less than 10 years. The majority of

patients (66%) were receiving monotherapy, most with diuretics

(43%) (Table 2). Of the 34% of patients on combined therapy,

a notable proportion (17%) was receiving a fixed combination

of an angiotensin converting enzyme and a thiazide diuretic.

With regard to non-antihypertensive drugs, 29, 9 and 6% of