CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 8, September 2012
440
AFRICA
prevalence of LV hypertrophy among type 1 diabetes patients
with nephropathy.
26
Of note, in the present study population, all type 1 diabetes
patients with LV hypertrophy also had albuminuria (results not
shown), and albuminuria was identified as a main covariate of
LV hypertrophy in multivariate analysis. The beneficial impact of
renin–angiotensin inhibition on albuminuria and the prevention
of overt renal failure has previously been demonstrated in
type 1 diabetes patients with microalbuminuria.
27
Whether the
prevention of progression to overt renal failure with the use of
drugs that inhibit the renin–angiotensin system will also prevent
progression to LV hypertrophy among type 1 diabetes patients is
a question that needs to be answered in future prospective studies
in Africans.
The finding that higher RWT was significantly associated
with older age and higher blood pressure agree with previous
reports from epidemiological studies in NorthAmerican Indians.
3
Importantly though, as demonstrated by multivariate analysis in
our study, independent associations between increased RWT
and measures of systolic and diastolic LV function were found
irrespective of presence or absence of LV hypertrophy or
hypertension. This is an important finding because it emphasises
the need to further stratify patients into the different LV geometric
patterns, rather than by presence or absence of LV hypertrophy
alone. The finding is particularly important in the African
diabetes context, as concentric remodelling (increased RWT
with normal LVMI) was found to be the most common abnormal
LV geometric pattern in the present study, as also previously
reported among African American hypertensive patients.
4
In 884 children and adolescents with a high prevalence of
obesity, Di Bonito
et al
.
found that higher triglyceride-to-HDL
cholesterol ratio independently predicted higher RWT and
concentric LV hypertrophy.
28
In our study, lower serum HDL
cholesterol levels, but not triglyceride-to-HDL cholesterol ratio,
were associated with higher RWT in type 2 diabetes patients,
only in univariate analysis. The differential findings probably
reflect differences in prevalence of obesity and degree of
myocardial fat storage between the two populations.
29
In the LIFE study, concentric remodelling was associated
with a three and eight times increased risk of stroke and
cardiovascular death after 4.8 years of follow up, respectively.
30
So, in a way, our findings may be explaining the link between the
increased prevalence of congestive heart failure and stroke seen
among black diabetic patients.
31
Of note, an independent association between gender and
measures of LV geometry was not found in the present study
population, partly contrasting with findings inAfricanAmericans
participating in the Atherosclerosis Risk in Community (ARIC)
study, which reported that diabetic women had more concentric
LV geometry, but similar prevalence of LV hypertrophy as men.
32
We have shown that a simple algorithm using every-day
clinical and laboratory tests (type of diabetes, hypertension,
obesity and albuminuria) may be used to identify three out of
four high-risk diabetic patients with increased RWT. This is very
important in a setting such as Tanzania where echocardiography
is not readily available. Of note, following this algorithm, a
patient with type 2 diabetes with any of the other three risk
factors, or a type 1 diabetes patient having any two of the other
three risk factors will have a 76% chance of having cardiac
target-organ damage as well.
Conclusion
We have shown that abnormal LV geometry was common in this
diabetic population. In particular, increased RWT was present
in 58% of patients and demonstrated as a marker of subclinical
cardiac target-organ damage. Furthermore, using the clinical risk
factors, type of diabetes, hypertension, obesity and albuminuria,
76%
of diabetic patients with increased RWT can be identified.
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