Amid concerns that automated insulin delivery (AID) systems can worsen diabetic retinopathy, an Australasian study has demonstrated most people with type 1 diabetes can achieve stable or improved disease in the short term.
The University of Otago-led study set out to investigate the impact AID systems – a relatively new technology allowing rapid improvements in glucose control – after concerns it may lead to early worsening of diabetic retinopathy, or progression during the first year.
It is still unclear which pathophysiological mechanisms may cause this, but variations in the somatotropic axis and higher retinal concentrations of angiogenic factors have been suggested in the literature.
Professor Ben Wheeler and Dr Francesc March de Ribot led the work, which also involved Dr Mary Abraham from Western Australia’s The Kids Research Institute and Perth Children’s Hospital, demonstrating how the new technology can be considered generally safe for the eyes.
“We looked at the short-term effects of diabetic retinopathy in people aged 13 and older with type 1 diabetes after using automated insulin delivery systems for more than six months,” Dr March said.
“We included 165 people and we demonstrated that most participants, 79%, saw improvements or no change in their diabetic retinopathy, with younger age being a protective factor.”
AID systems have become more commonplace in diabetes management with the US Food and Drug Administration approving the first system in 2016. In Australia, 25,000 patients use these devices and in New Zealand, more than 4,000, “emphasising the widespread adoption of this technology in our countries”, Dr March said.
They combine an insulin pump, a continuous glucose monitor, and an algorithm that automatically adjusts and/or boluses insulin to keep blood glucose levels within a target range.
Plus, research on people with very unhealthy glycemia suggests that dramatic and rapid improvements are possible for many.
Dr March and his team conducted a retrospective, four centre observational study with participants drawn from hospital databases in Dunedin and Christchurch, New Zealand, and from two research studies based out of Auckland and Perth.
Diabetic retinopathy grading data from the 165 participants involved three different AID systems, and mean improvement in HbA1c – a blood test used to monitor blood glucose control – for the total sample was 1.0-1.3 percentage points.
Improvements in grading were seen in 32/165 (19%) of participants, 99/165 (60%) were considered stable, and 34/165 (21%) worsened.
Age at AID initiation, more than 18 years, was the only significant risk factor for any worsening of diabetic retinopathy.
Proliferative change and the need for photocoagulation treatment were uncommon but did occur in 3% (5/165); all had prior diabetic retinopathy, diabetes duration of more than 10 years, and with at least another diabetes-related complication or prior retinopathy treatment.
Improving glycemia “far outweighs” risk of short-term diabetic retinopathy
The study is the first to report changes in diabetic retinopathy grading following the initiation of AID treatment.
Overall, the researchers said the study “helps to demonstrate the general safety of AID, as the vast majority of participants showed improvement, stability, or minimal worsening of diabetic retinopathy (to no more than minimal/mild disease) in the months following AID initiation”.
“However, early worsening of diabetic retinopathy that needed treatment was seen in less than 4%, a rate like that seen in a recent systematic review investigating different types of intensive therapy,” they said.
But it was important to emphasise that the benefits of improving glycemia remain crucial and “far outweigh the risk” of short-term diabetic retinopathy deterioration. This is because it is rare and can be successfully managed.
“These outweighing benefits have been clearly demonstrated in the past studies and highlight that in the longer term, improved glycemia results in reduced risk of progression of diabetes complications, including diabetic retinopathy (a 76% reduction in the risk for progression after 6.5 years of follow-up).
“Thus, the risk of diabetic retinopathy deterioration in the short term should not prevent AID use, but for those at higher risk, including longer diabetes duration and coinciding diabetes complications at baseline, a closer follow-up and monitoring may be needed, with the main goal of early detection of proliferative diabetic retinopathy.”
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