SA JOURNAL OF DIABETES & VASCULAR DISEASE
REVIEW
VOLUME 7 NUMBER 2 • JUNE 2010
67
line triglyceride level and a low baseline level of high-density lipoprotein
cholesterol’, but this category of dyslipidaemic patient represented only
17% (941 out of the 5 518) of the total patients in the study’, Prof Raal
concluded.
The significance of microalbuminuria
Dr Trevor Gernholtz, private practice nephrologist, Fourways,
Gauteng
Dr Trevor Gernholtz at the outset sought to define the best methods of
determining microalbuminuria. Noting that the measurement of urinary
albumin excretion (UAE) in a 24-hour collection is the gold-standard
method of determining the presence and extent of microalbuminuria, it
clearly no longer meets the demands of immediate clinical availability.
In the search to define what techniques could best replace the
24-hour urine collection, Dr Gernholtz noted recent methodological
research in Groningen, Netherlands,
9
which has shown that the deter-
mination of the albumin:creatinine ratio (ACR) or the urinary albumin
concentration (UAC) in the first morning void (FMV) relates best with
the 24-hour UAE and was more consistent than the spot urine-sam-
pling technique.
‘ACR in a FMV is the screening method of choice to determine
the presence of early diabetic renal disease, yet its predictive value for
determining the rate of progression of kidney disease is not consistent’,
Dr Gerntholtz noted.
Referring to the STENO trial,
10
Dr Gerntholtz pointed out that type
2 diabetic patients treated with RAAS blockers achieved better blood
pressure control and improvements in urinary albumin excretion rates,
but over the eight years, there was no difference in the decline in
glomerular filtration rates (GFR) in the intensive versus the non-inten-
sive arm.
‘Over the eight years, there was an overall 3 to 4 ml/min decline in
the GFR despite effective BP control, lifestyle modification and improved
glucose and lipid control’, Dr Gerntholtz noted. ‘The intensive therapy
did reduce all-cause and cardiovascular mortality and only one patient
in the intensive arm progressed to end-stage renal disease versus the six
patients in the conservatively treated group’, he added.
A further series of studies indicative of a disconnection between
microalbuminuria and declining kidney function was undertaken by G
Jerums in Australia in 2008.
11
‘His studies showed that in late diabetic
nephropathy only (both type 1 and type 2 diabetes) did reduction of
albuminuria translate to a slower deterioration in glomerular filtration
rate.’
‘Microalbuminuria is more indicative of vascular changes in the
kidney and also in the rest of the body than it is indicative of renal
lesions. There is a wide range of structural renal lesions over similar
ranges of normo/microalbuminuria.’
Notwithstanding the poor correlation with kidney function and
microalbuminuria, albuminuria is a continuum from normal (
<
30 mg/
day) to microalbuminuria (30–300 mg/day) to frank albuminuria (
>
300
mg/day). Also, before a patient develops frank albuminuria, it is pre-
ceded by microalbuminuria, so that its detection remains important.
For this reason, it is recommended that urine (FMV) be sent off on a
six- to 12-monthly basis to assess the albumin:creatinine ratio.
The importance of risk assessment in coronary artery
disease management
Dr Colin Schamroth, private practice cardiologist, Milpark,
Gauteng
‘Risk factor scores are important; yet the Framingham Heart study
showed that a third of coronary artery disease (CAD) events occur at
normal cholesterol levels and a fifth occur among individuals without
recognised traditional risk factors (blood pressure, smoking status,
hyperlipidaemia and the presence or absence of diabetes). The Fram-
ingham-derived scoring system, although used successfully for many
years, has limitations, particularly in women, black patients, younger
patients and with the ever-increasing presence of the metabolic syn-
drome.’ This view was expressed by Dr Colin Schamroth in his presenta-
tion on risk-factor models and the need for updating the 1980s-based
Framingham score.
12
‘The addition of hsCRP (high sensitivity C-reactive protein) has
received a great deal of attention and it certainly adds value as a clini-
cal criterion for the metabolic syndrome and is capable of refining risk
in those patients at intermediate risk (10–20%),
13
as determined by the
Framingham score. I use the Reynolds risk score, available on the inter-
net
), to assess risk and show the patient
how modification of risk factors by lifestyle or therapeutics reduces his/
her risk of future cardiovascular events.’
The advantage of hsCRP is that the test is quick, standardised and
not expensive. Looking at specific population groups, the Northern
Manhattan Cohort study
14
added factors such as weight circumference,
alcohol consumption and physical activity as determining cardiovascu-
lar risk in this multi-ethnic population. However, the addition of these
factors added very little predictive value over and above the Framing-
ham risk score.
A comprehensive study
15
undertaken of whether erectile dysfunc-
tion could contribute to the prediction of cardiovascular risk was nega-
tive, although the presence of erectile dysfunction was significantly
associated with cardiovascular incidence.
Electron-beam computed tomographic determination of coronary
artery calcium showed that in a cohort of apparently healthy, middle-
aged men, calcium determination contributed very little to the risk of
already-determined Framingham risk of above 20%. Below 10%, coro-
nary artery calcium was however negatively predictive and added value
to the Framingham score. ‘Importantly, in the intermediate-risk group
of 10 to 20%, a low calcium score did indicate a lesser risk.’ However,
this is an expensive technique, and adds little to the predictive value of
Framingham with hsCRP (the Reynolds risk score).
Finally, the use of genetic testing using defined SNPS
16
(9p21
genomic markers), undertaken as part of the Women’s Genome Health
project, showed a net reclassification of the risk index from 0.1 to 4.8%.
Genetic definition is still unhelpful at this stage of our knowledge’, Dr
Schamroth concluded.
The management of silent myocardial ischaemia:
intervention or non-intervention?
Dr Adrian Horak, cardiologist, Vincent Pallotti Hospital, Cape
Town
Dr Adrian Horak made the case very strongly for intervention. ‘No con-
test!’, he said.
For the purposes of his talk, Dr Horak said he was viewing silent
myocardial ischaemia as being equivalent to normal ischaemia. ‘It is
the same’, he said, ‘with the only difference being that there are no
symptoms and the patient is therefore unaware of the problem’. Silent
ischaemia is more prevalent in diabetics.
He pointed out that doing nothing is an option, as is medical
treatment, but that he would be focusing primarily on percutaneous
coronary intervention (PCI) (angioplasty/stenting) and coronary artery
bypass grafting (CABG).
‘In some respects it’s a silly topic to be debating as all patients are
individuals and what may be right for one may not be right for another.
Careful assessment is important to weight up the risk of intervention
