VOLUME 11 NUMBER 3 • SEPTEMBER 2014
103
SA JOURNAL OF DIABETES & VASCULAR DISEASE
REVIEW
demonstrated its benefit in DR.
16
These two trials together included
21 000 participants, of whom over 10 000 received fenofibrate.
Although these trials primarily looked at cardiovascular effects,
both had large retinopathy subsets.
The ACCORD study consistently showed benefit in reducing
progression of DR. The FIELD study showed that 40% fewer
patients taking fenofibrate had significant DR progression than the
control group after five years (10.2 vs 6.5%). Additionally, 30%
more patients in the control group required laser therapy than in
the fenofibrate group (3.6 vs 5.2%).
16
Drugs for anaemia treatment
Erythropoietin is a potent ischaemia-induced angiogenic factor
during retinal angiogenesis in DR.
17
Patients receiving erythropoietin
should have their retinopathy closely monitored, especially if in
combination with anaemia and kidney disease.
Drugs for cardiac complications management
Both salicylates and digoxin have the theoretical ability to be
advantageous in DR.
Salicylates
Aspirin-like substances may be useful in early DR to slow pro-
gression. As early as 1964, the effects of large doses of salicylates
on DR have been reported and recent studies show a positive effect
on DR in animals. Doses of 2 to 4 mg per day in humans could
delay the progression of DR. New advances in nanotechnology
imply that salicylates could be formulated as an eye drop for
topical use.
18
One of the complications of proliferative diabetic retinopathy is
that of loss of vision due to vitreous haemorrhage. Systemic aspirin
has been proven not to increase this risk
19
and neither does warfarin
nor heparin.
20
Digoxin
Digoxin has been found to block hypoxia-induced expression
of multiple angiogenic genes and is also a powerful inhibitor of
neovascularisation of the retina and choroid layer.
21
The FDA has
recently begun trials on a topical application.
Anti-angiogenic drugs and steroids
Both of these agents only improve DR (proliferative DR as well
as macular oedema) when injected intra-ocularly. Systemic
administration of both has a negligible effect and steroids can
make glycaemic control difficult, and potentially worsen DR.
Conclusion
Although good serum glucose control and regular fundoscopy are
most important for managing diabetic retinopathy, there are other
strategies we can use to modify the outcome of this disease. A
careful choice of systemic medication, especially for hypertension,
hyperlipidaemia, anaemia and cardiac complications management
can assist in decreasing irreversible loss of vision in diabetic
patients.
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