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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 4, July/August 2018
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AFRICA
Furthermore, among those who knew they had hypertension,
less than half were on treatment. This is similar to what earlier
studies found, and this carries a great risk for the complications
of diabetes, especially CVDs such as stroke, LVH, myocardial
infarction, as reported by the United Kingdom Prospective
Diabetes Study (UKPDS). In one cross-sectional study among
people with hypertension in Uganda, less than 10% were
controlled. In another retrospective study conducted in an urban
diabetes clinic in Kampala, optimal blood pressure control,
defined as
≤
140/80 mmHg, was noted in 56% of the patients.
43
This corroborates the notion that blood pressure control among
adult diabetic patients in Uganda is sub-optimal. This calls
for the development and implementation of local guidelines
to improve diabetes care and minimise complications due to
hypertension.
43
Possible reasons for this very low level of control may be that
the majority of people with hypertension are not aware they
have the condition, and even among those who are aware, less
than half are receiving treatment. However, even among those
receiving treatment, only one in three achieve blood pressure
control. A worrying global trend is that low levels for the control
of hypertension are widespread in both low- and high-income
countries.
7,40,44,45
There is an additional risk reduction with ACE inhibitors and
β
-blockers over and above that associated with lowering of blood
pressure among diabetics.
12
However, the use of ACE inhibitors/
ARBs among those who knew their status was in only one-third
of all participants, yet we know that ACE inhibitors reduce the
risk for nephropathy and other complications of diabetes, such
as LVH. For this reason, the JNC 7 and JNC 8 recommend that
every diabetic who has hypertension must be started on ACE
inhibitors/ARBs among other treatment options.
46
In patients with type 2 DM, hypertension is associated
with LVH.
20,21
According to the Appropriate Blood Pressure
Control in Diabetes (ABCD) trial, LVH is an independent
predictor of cardiovascular events in hypertensive patients with
diabetes.
22
Hypertension is also a major risk factor for myocardial
infarction and stroke,
12,23,24
and indeed it is the leading risk factor
for mortality worldwide.
5,25-27
Therefore prevention and control
of hypertension are critical in reducing morbidity and mortality
attributable to cardiovascular diseases among diabetics.
According to the UKPDS, the incidence of clinical
complications among diabetics is significantly associated with
systolic blood pressure, except for cataract extraction. Each
10 mmHg decrease in updated mean systolic blood pressure is
associated with risk reductions of 12% for any complication
related to diabetes, 15% for deaths related to diabetes, 11% for
myocardial infarction and 13% for microvascular complications.
Any reduction in blood pressure is likely to reduce the risk of
complications, with the lowest risk being in those with systolic
blood pressure less than 120 mmHg.
12
An upcoming comprehensive review of global publications
on NCD costs from low- and middle-income countries confirms
that primary prevention of CVD, stroke and diabetes is far less
expensive and has lower unit costs than treatment interventions
for these conditions. One way to achieve this is to control
hypertension.
34
The following factors were associated with hypertension
among the newly diagnosed diabetics in the bivariate model:
age above 40 years, female gender, unemployment, lack of
physical exercise, overweight and obesity, increased waist:hip
ratios, LVH and diastolic dysfunction. However after adjusting
for possible confounders, only unemployment, gender and
increasing BMI were independently associated with hypertension
in this model. Among these factors, unemployment and BMI are
modifiable, while gender is the non-modifiable factor associated
with hypertension.
Attaining and maintaining a healthy weight improves blood
pressure and diabetes management, and reduces cholesterol
levels. The Trials of Hypertension Prevention (TOHP) study
showed that a decrease of 4.4 kg can lead to a blood pressure
reduction of 4/3 mmHg.
16
In a study to determine the prevalence and factors associated
with hypertension among residents of the rural district of
Rukungiri, Uganda, some of the factors found to be associated
with hypertension included: being overweight or obese, female
gender and older age.
37
However all these factors, apart from
obesity and being overweight, had no significance in our study in
the multivariate model. The reason could be that Wamala
et al
.
37
in the earlier study had a bigger sample size compared to ours
and enrolled community members, while our population was for
newly diagnosed diabetics.
Similar findings have been reported by Wamala and
co-workers
37
and Musinguzi
et al
.
7
in other cross-sectional
studies. These observations suggest that demographic transition,
urbanisation and increasing life expectancy are major
determinants of prevalence of hypertension among diabetics.
7,47-49
In a population-based, cross-sectional survey, Baziel
et al
.
1
found further evidence to show that increasing BMI and a
waist circumference above the normal range were associated
with hypertension. In the same study, sociodemographic factors
associated with hypertension included increasing age, male
gender, overweight and obesity.
With the substantial burden of hypertension in Uganda
coupled with low awareness and limited treatment of
hypertension, especially among diabetics, enhanced community-
based education and prevention efforts tailored to addressing
modifiable factors are needed.
5
In our study, participants who
were employed were 63% less likely to have hypertension
compared to their unemployed counterparts. One possible
explanation would be the lack of physical exercise among the
unemployed participants, whereas those who are working often
do manual labour in most parts of sub-Saharan Africa.
As observed elsewhere, the prevalence of hypertension
increases with increasing age, and the increase is more marked
among women than men.
33,50
We found age above 40 years to be
associated with hypertension in the bivariate model, however
this level of significance was lost in the multivariate model. With
increasing life expectancy, the risk of hypertension becomes
very important in sub-Saharan Africa, a region undergoing an
epidemiological transition.
In addition patients who had LVH and/diastolic dysfunction
were more likely to have hypertension compared to their
counterparts without these heart problems. However this was
no longer significant at multivariate level. One of the possible
explanations could be that hypertension among diabetics caused
LVH and diastolic dysfunction, as cited in the ABCD trial and
other studies.
22
Therefore treating hypertension would be one
way to prevent these complications because 75% of all CVD in
diabetics can be attributed to hypertension.