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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 25, No 5, September/October 2014
AFRICA
229
hypertensive retinopathy and other TOD has largely remained
unexplored. The aim of this study was to examine the association
of hypertensive retinopathy with LVH, chronic kidney disease
(CKD) and stroke in Congolese patients.
Methods
This cross-sectional, observational study included 159 consecutive
Congolese hypertensive patients (73 men, 86 women, mean age
57.9
±
13.2 years) who were referred from the Cardiology
Division to the Ophthalmology Department of the Kinshasa
University Hospital for fundus examination as part of a work-up
of people with hypertension. All participants provided informed
consent and the study was approved by the University of
Kinshasa Medical School institutional review board.
Inclusion criteria were age
≥
18 years, willingness to participate
in the study, established diagnosis of hypertension regardless of
treatment regimen, duration, severity or aetiology. Exclusion
criteria included inaccessibility of the fundus due to media
opacities, and pregnancy.
All participants underwent blood pressure measurement
with a mercury sphygmomanometer after the patient has been
in a sitting position for five minutes, and body mass index
(BMI) determination. They provided personal information
about history of alcoholism, smoking, as well as family history
of hypertension and stroke, and diabetes.
Routine ophthalmological examination was performed, which
included measurement of visual acuity, slit-lamp examination of
the anterior segment, intra-ocular pressure measurement with
applanation tonometry, and ocular fundus assessment with direct
ophthalmoscopy after pupil dilation with tropicamide 1% and
phenylephrine 10%. The fundus examination specifically looked
at retinal abnormalities consistent with hypertensive retinopathy,
which was graded based on the Scheie classification:
14
grade
0
=
no visible change; grade 1
=
barely detectable arterial
narrowing; grade 2
=
obvious arterial narrowing with focal
irregularities; grade 3
=
grade 2 plus retinal haemorrhages,
exudates, cotton wool spots, or retinal oedema; grade 4: grade 3
plus papilloedema.
Hypertension was defined and classified according to
the European Society of Hypertension/European Society of
Cardiology guidelines.
15
Data about extra-ocular TOD such
as LVH, CKD and stroke were recorded from cardiology
medical records. LVH was diagnosed by echocardiogram using
ASE criteria:
16
end-systolic left ventricular diameter, septal wall
thickness (SWT) and posterior wall thickness were calculated
from the two-dimensionnally guided M-mode tracing and
measured in five consecutive cardiac cycles. LVH was defined by
SWT greater than 11 mm.
CKDwas diagnosedaccording to theKidneyDiseaseOutcome
Quality Initiative (K/DOQI),
17
when glomerular filtration rate
(GFR) was lower than 60 ml/min/1.7 m² using the equation from
the Modified Diet in Renal Disease (MDRD) study.
18
Stroke was
diagnosed in the presence of clinical neurological signs consistent
with stroke, with or without supporting CT scan lesions.
Statistical analysis
All analyses were performed with SPSS version 15.0 (SPSS,
Chicago, IL, USA). Data were expressed as mean
±
standard
deviation. Student’s
t
-test was used to compare means between
groups. The proportion of patients with hypertensive retinopathy
was compared among those with and without LVH, CKD or
stroke using the chi-square test. The chi-square test was also
used to compare the proportions of patients with TOD between
those with and without hypertensive retinopathy. Multiple
logistic regression analysis allowed assessment of the association
of demographic and clinical factors including TOD with the
likelihood of having hypertensive retinopathy. A
p
<
0.05 was
considered statistically significant.
Results
Of the 159 patients included in this study, 73 (46%) were male
and 86 (54%) were female, with a mean age of 57.9
±
13.2 years
(range: 19–92). Approximately half of the patients (48.4%) had
been hypertensive for one to 10 years; 137 (86.2%) patients had
essential hypertension and 22 were diabetic. Hypertension was
grade 1 (systolic: 140–159 mmHg and diastolic: 90–99 mmHg),
grade 2 (systolic: 160–179 mmHg, diastolic: 100–109 mmHg)
and grade 3 (systolic
≥
180 mmHg, diastolic
≥
110 mmHg) in
48 (30.2%), 34 (21.4%) and 77 (48.4%) patients, respectively.
One hundred and twenty-two (76.7%) patients were on blood
pressure-lowering treatment (57.2% had uncontrolled whereas
19.5% has controlled blood pressure) and 37 (23.3%) were not
on treatment at the time of study enrolment.
Other characteristics of the study population were as follows:
weight 71.8
±
16.3 kg (range: 42–130), height 163.5
±
8.9 cm
(range: 148–162), waist circumference 90.9
±
12.8 cm (range:
67–125), systolic blood pressure 159.1
±
30.9 mmHg (range:
100–230), diastolic blood pressure 95.1
±
16.6 mmHg (range:
61–157), serum creatinine 2.2
±
3.6 mg/dl (range: 0.3–19) and
blood urea 38.9
±
42.1 mmol/l (range: 5.2–258).
Hypertensive retinopathy stage 0, 1, 2, 3 and 4 was present
in 16.4, 42.1, 11.3, 23.3 and 6.9% of the patients, respectively.
Overall, the severity of hypertensive retinopathy increased
with increasing systolic and diastolic blood pressures. Data
on cardiac state were available for 97 (61%) patients, of whom
52 (53.6%) had LVH. Twenty-eight (31.8%) of the 88 patients
who underwent glomerular filtration rate (GFR) assessment
had levels consistent with CKD and 28 (17.6%) patients were
diagnosed as having stroke.
Table 1 shows the distribution of patients with LVH by stage
of retinopathy. The proportions of patients with retinopathy
were comparable among those with (86.5%) and without LVH
(73.3%) (
χ
2
=
1.53,
p
=
0.21). Similarly, the proportions of
patients with LVH did not differ significantly between patients
with (57.7%) and those without retinopathy (36.8%) (
χ
2
=
0.39,
p
=
0.53). There was no significant association between
hypertensive retinopathy and LVH (
χ
2
=
1.9,
p
=
0.17, OR
=
2.3,
95% CI: 0.8–6.6). For all retinopathy stages, the proportions of
patients with and without LVH were comparable (
p
=
0.24–0.99,
data not provided in Table 1). The risk of having LVH tended to
increase with the severity of hypertensive retinopathy; it was 4.5
times higher for patients with grade 3 hypertensive retinopathy
relative to those without retinopathy.
There were 28 patients with CKD; their distribution by
retinopathy stage is provided in Table 2. Subgroups of patients
with and without retinopathy had similar proportions of patients
with CKD (33.3 vs 23.1%) (
χ
2
=
0.088,
p
=
0.77). A similar