ABSTRACTS
SA JOURNAL OF DIABETES & VASCULAR DISEASE
128
VOLUME 7 NUMBER 3 • SEPTEMBER 2010
Mild progression of retinopathy
occurs during pregnancy in type 2
diabetic women
This study of more than 100 pregnant
women with type 2 diabetes showed that
progression of diabetic retinopathy was
associated with a longer duration of diabe-
tes and insulin treatment prior to pregnancy.
Fundus photography was performed at
about 10 weeks of pregnancy, and in the
third trimester at about 28 weeks (range
27–37). Diabetic retinopathy was present in
14% of women in early pregnancy and one
in seven progressed during the pregnancy.
Only one had sight-threatening diabetic
retinopathy following poor compliance with
treatment for glycaemic control and hyper-
tension management.
The strength of the study is that the
population was an unselected cohort. Clini-
cians should be aware of the need to screen
for retinopathy and warn their patients that
poor compliance could compromise their
vision.
Source: Rasmussen KL, Laugesen CS, Ringholm L,
Vestgaard M, Damm P, Matheisen ER. Progression of
diabetic retinopathy during pregnancy in women with
type 2 diabetes.
Diabetologia
2010;
53
: 1076–1083.
DOI: 10.1007/s00125 010-1697-9.
Increased risk of severe retinopathy
in type 2 diabetics with sub-clinical
hypothyroidism
This study of the relationship between sub-
clinical hypothyroidism and diabetic retin-
opathy in a large cohort of type 2 diabetic
patients in China has highlighted the statis-
tically significantly increased risk of retinopa-
thy in patients with this endocrine disorder.
Sub-clinical hypothyroidism was defined
as normal free FT3 and FT4 levels but with
increased TSH. These patients were matched
to 200 randomly selected euthyroid type 2
diabetic patients.
After adjustment for potential variables
(age, duration of diabetes, HbA
1c
levels, BMI,
blood pressure and blood lipid levels), sub-
clinical hypothyroidism was associated with
diabetic retinopathy (odds ratio: 2.02).
This study emphasises that sub-clinical
hypothyroidism is complicated by endothe-
lial dysfunction and raised high-sensitivity
C-reactive protein levels, which are likely to
be responsible for the increase in retinopa-
thy.
Source: Yang JK, Li YB, Liu W, Siu J. An association
between subclinical hypothyroidism and sight-
threatening diabetic retinopathy in type 2 diabetic
patients.
Diabetes Care
2010;
33
(5): 1018–1020.
Blockade of the renin–angiotensin
system slows retinopathy progres-
sion in type 1 diabetes
A multi-centre, double-blind, controlled trial
of normotensive type 1 diabetic patients
with normo-albuminuria has shown that
blockade of the renin–angiotensin system
using either losartan (100 mg daily) or enal-
april (20 mg daily) slowed the progression of
retinopathy but not nephropathy.
This study was investigator-initiated in
the USA and recruited 285 type 1 diabetic
patients of 18 years and older who were
normotensive (
<
135/85 mmHg). They were
followed for five years.
Primary endpoint was a change in the
fraction of glomerular volume occupied by
the mesangium in kidney biopsy specimens.
The retinopathy endpoint was progression
on a retinopathy severity scale of two steps
or more.
Compared to placebo, the odds of retin-
opathy progression were reduced by 65%
with enalapril and by 70% with losartan,
independent of changes in blood pressure.
The beneficial effects of early use of
renin–angiotensin blockers may represent
direct effects on the eye, independent of the
effects of systemic blood pressure.
Source: Mauer M, Zinman B, Gardiner R, Suissa S, Sinaido
A, Strand T, Drummond K, et al. Renal and retinal effects
of enalapril and losartan in type 1 diabetes.
N Eng J Med
209;
361
: 40–51.
Experimental studies on low-dose
erythropoietin shows beneficial
vascular retinal changes
The use of epoetin delta, as administered to
diabetic Wistar rats, showed that this agent
reduced oxidative and nitrosative stress in
the retinal, kidney and heart tissues of the
experimental animals.
The dose of erythropoietin was chosen at
a lower level and did not alter haematologi-
cal variables. Epoetin delta reduced retinal
angio-poietin 2 expression and pericyte loss
in the retina.
These studies of the experimental use of
sub-erythropoietic doses show promise and
should be extended in other experimental
studies of larger animals.
Source: Wang Q, Pfister F, Dorn-Beineke A, von Hagen
F, Lin J, Feng Y, Hammes HP. Low-dose erythropoietin
inhibits oxidative stress and early vascular changes in
the experimental diabetic retina.
Diabetologia
2010;
53
:
1227–1238.
Lower dose of bevacizumab (avas-
tin) effective as pre-operative
adjunct therapy
A lower dose (0.16 mg) of bevacizumab
was as effective as the standard dose (1.25
mg) in reducing vitreous vascular endothe-
lial growth factor (VEGF) concentration and
intra-operative bleeding during vitrectomy.
This clinical study of 52 patients who
were given varied doses of bevacizumab or
placebo, three days before vitrectomy for
proliferative diabetic retinopathy, showed
that the intravitreal bevacizumab reduced
the number of intra-operative coagulation
spots, compared to placebo.
The lower dose of bevacizumab may help
to avoid ocular complications such as retinal
detachment.
Source: Hattori T, Shimada H, Nakashizuka H, Mizutani
Y, Mori R, Yuzawa M. Dose of intravitreal bevacizumab
(avastin) used as preoperative adjunct therapy for
proliferative diabetic retinopathy.
Retina
2010;
30
: 761–
764.
Useful summary of standards of
medical care in diabetes
Diabetes Care
has published a useful execu-
tive summary of current recommendations
concerning type 2 diabetes from diagnosis
to monitoring and risk-factor management.
The summary of retinopathy screening and
treatment in diabetic patients is pertinent to
clinical care and is provided below with the
level of evidence indicated in parenthesis.
Screening
• Adults and children aged 10 years or
older with type 1 diabetes should have
an initial dilated and comprehensive eye
examination by an ophthalmologist or
optometrist within five years of the onset
of diabetes (B).
• Patients with type 2 diabetes should have
an initial dilated and comprehensive eye
examination by an ophthalmologist or
optometrist shortly after the diagnosis of
diabetes (B).
• An ophthalmologist or optometrist
for type 1 and type 2 diabetic patients
should repeat subsequent examinations
annually. Less-frequent examinations
(every two to three years) may be con-
sidered following one or more normal
eye examinations. Examinations will be
required more frequently if retinopathy is
progressing (B).
• High-quality fundus photographs can
detect most clinically significant diabetic
retinopathy. A trained eyecare provider
