CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 7, August 2012
AFRICA
379
Target-organ damage and cardiovascular complications
in hypertensive Nigerian Yoruba adults:
a cross-sectional study
OO OLADAPO, L SALAKO, L SADIQ, K SHOYINKA, K ADEDAPO, AO FALASE
Abstract
Background:
Hypertension is a major challenge to public
health as it is frequently associated with sudden death due
to the silent nature of the condition. By the time of diagnosis,
some patients would have developed target-organ damage
(TOD) and associated clinical conditions (ACC) due to low
levels of detection, treatment and control. TOD and ACC
are easy to evaluate in a primary healthcare (PHC) setting
and offer valuable information for stratifying cardiovascular
risks in the patient. The aim of this study was to evaluate the
prevalence and correlates of TOD and established cardiovas-
cular disease (CVD) in hypertensive Nigerian adults.
Methods:
A cross-sectional study was conducted on 2 000
healthy Yoruba adults between 18 and 64 years who lived in
a rural community in south-western Nigeria. Participants
diagnosed to have hypertension were examined for TOD and
ACC by the presence of electrocardiographically determined
left ventricular hypertrophy (LVH), microalbuminuria or
proteinuria, retinopathy, or history of myocardial infarction
and stroke.
Results:
A total of 415 hypertensive participants were exam-
ined and of these, 179 (43.1%) had evidence of TOD and
45 (10.8%) had established CVD. TOD was associated with
significantly higher systolic (SBP) and diastolic blood pres-
sure (DBP). The prevalence of LVH was 27.9%, atrial fibril-
lation 16.4%, microalbuminuria 12.3%, proteinuria 15.2%,
hypertensive retinopathy 2.2%, stroke 6.3%, congestive
heart failure (CHF) 4.6%, ischaemic heart disease 1.7%, and
peripheral vascular disease 3.6%. Compared with those with
normal blood pressure (BP), the multivariate adjusted odds
ratios (95% confidence interval) of developing TOD was 3.61
(0.59–8.73) for those with newly diagnosed hypertension;
4.76 (1.30–13.06) for those with BP
≥
180/110 mmHg; and
1.85 (0.74–8.59) for those with diabetes mellitus.
Conclusions:
This study provides new data on TOD and its
correlates in a nationally representative sample of hyperten-
sive adults in Nigeria. In this low-resource setting, attempts
should be made to detect hypertensive patients early within
the community and manage them appropriately before irre-
versible organ damage and complications set in. The methods
used in this study are simple and adaptable at the primary
healthcare level for planning prevention and intervention
programmes.
Keywords:
target-organ damage, left ventricular hypertro-
phy, microalbuminuria, retinopathy, established cardiovascular
disease, hypertension, Nigeria
Submitted 3/4/11, accepted 6/3/12
Cardiovasc J Afr
2012;
23
: 379–384
DOI: 10.5830/CVJA-2012-021
Hypertension is often asymptomatic and recording blood
pressure is opportunistic. Many of these patients are unaware
of their condition and therefore remain untreated. Untreated or
poorly controlled hypertension and left ventricular hypertrophy
(LVH) are risk factors for cardiovascular diseases (CVD),
1
a
major cause of morbidity and mortality, and sudden death.
2
The
lack of awareness of the disease results in worse outcomes.
A number of hypertensives may present for the first time with
target-organ damage (TOD) involving various organs. Therefore
at initial diagnosis, they already have hypertensive heart disease
(HHD); some with LVH, while some have frank congestive heart
failure (CHF). CHF is a lethal disease with a poor prognosis and
reduced life expectancy.
3
It imposes a large health, economic and
social burden on the patient, his/her family and the community at
large, and it usually affects males and females in their productive
middle years.
Major TOD of hypertension such as LVH,
4
diastolic
dysfunction,
5
CHF,
6
ischaemic heart disease (IHD),
7
stroke
8
and renal failure
9
have been documented by various workers
in Nigeria and these were mostly hospital-based studies.
Autopsy studies confirmed that the commonest cause of sudden,
unexpected death in Nigerians is hypertension.
10,11
In Nigeria, little is known about the experiences of caregivers
and care-seeking practices with regard to hypertension and
factors influencing late presentation with TOD. Some of the
undiagnosed hypertensives are detected incidentally during the
course of management for other clinical conditions or during
catastrophic events. The challenge to the physician therefore is
Department of Medicine, Cardiovascular Unit, University
College Hospital, and Department of Anatomy, College of
Medicine, University of Ibadan, Nigeria
OO OLADAPO, MB BS, MSc, FWACP,
University of Ibadan, Nigeria
L SALAKO, DSc
Country office, World Health Organisation, Lagos Nigeria
L SADIQ, MSc
Primary Health Egbeda Local Government, Oyo State,
Nigeria
K SHOYINKA, MB BS
Department of Chemical Pathology, College of Medicine,
University of Ibadan, Nigeria
K ADEDAPO, MB BS
Department of Medicine, Cardiovascular Unit, University
College Hospital, College of Medicine, University of Ibadan,
Nigeria
AO FALASE, MB BS, MD
