Cardiovascular Journal of Africa: Vol 28 No 5 (September/October 2017)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 5, September/October 2017 322 AFRICA
impairing bone marrow haematopoiesis are probably identical
to those that worsen the prognosis in CAD. These factors are
anaemia, iron deficiency, lipid disorders, chronic inflammation,
neurohumoral activation, glycaemic disturbance, vitamin D3
deficiency, oxidative stress and renal failure.17,18 Additionally,
red cell deformability diminution may result in impaired flow
through the microcirculation.17
Previous studies have shown an association betweenRDWand
the severity of CAD.11-13 Akin et al. investigated the association of
RDW with the severity of CAD in acute myocardial infarction
and showed that higher RDW values were correlated with higher
Syntax scores, which means more complex coronary lesions.
They found that after multiple logistic regression analysis, RDW
remained a significant predictor for the severity of CAD.11 Isik
et al. evaluated this relationship in patients with stable angina
pectoris and found an independent association between RDW
and the complexity of CAD, which was determined with Syntax
scores.12
A large Chinese cohort study with 677 subjects showed
significantly elevated RDW values in CAD patients and a
positive correlation between RDW and the Gensini score.13
They also found that a RDW value of 12.85% was an effective
cut-off point for predicting CAD, with a sensitivity of 50% and
a specificity of 65%. Recently, Sahin et al. concluded that RDW
values were independently associated with a high Syntax score
but were not associated with long-term mortality in patients with
non-ST-elevation myocardial infarction.19
In agreement with the current literature, we found that
elevation in RDW values was associated with both the presence
and complexity of CAD. Furthermore, we found that an RDW
value of 13.25% was an effective cut-off point in order to
determine the presence of CAD. Moreover, our study is the first
to show an association between RDW and CAD severity in a
diabetic population.
Chronic inflammation and neurohumoral activation are
thought to be the key factors for both a worse cardiovascular
prognosis and more complex coronary lesions.17,18 In our study,
hs-CRP levels were similar in the two CAD groups, but there was
a positive correlation between RDW and hs-CRP. Unfortunately,
we did not measure brain natriuretic peptides, which are markers
of the neurohumoral pathway. Some researchers demonstrated
that elevated mean platelet volume (MPV) was associated with
acute coronary syndromes, thrombosis and inflammation.20,21 We
also found a positive relationship between RDW and MPV.
It is well known that there is a link between glycaemic
disturbance and high RDW values. Two different studies showed
a relationship between glycosylated haemoglobin and RDW
in an unselected elderly population and in healthy adults.22,23
Garg et al. demonstrated that glycosylated haemoglobin was
an independent predictor of CAD severity in a non-diabetic
population.24 Our findings support the results of previous studies.
This study has some limitations. First, we did not measure
some factors that might have influenced RDW levels, such as
vitamin B12, folate and iron levels. Second, cardiovascular events
were not analysed due to the cross-sectional nature of the study.
Third, the relationship between RDW, glycaemic disturbance
and the severity of CAD could have been better understood if
we had analysed glycosylated haemoglobin levels. Lastly, the
diagnosis of DM was based on a previous history instead of
biochemical results.
Conclusion
RDW values were significantly higher in diabetic than
non-diabetic patients with CAD. Higher RDW values were
related to more extensive and complex coronary lesions,
suggesting that RDW may be a marker for predicting CAD
severity in patients with DM.
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