New Study Links Metformin to Reduced Risk of Age-Related Macular Degeneration (AMD)
Kehinde Adegoke | Daily Mail
A widely useddiabetes drug could help prevent the most common cause of blindness, according to a new study.
Doctors have found that Metformin, a type 2 diabetes medication that costs the NHS just 35p per pill, is associated with a lower progression of age-related macular degeneration (AMD).
AMD rarely causes permanent blindness, but it can cause blurry, distorted vision and blind spots, which can make reading and recognising faces difficult.
It is the leading cause of sight loss in older people, and it’s estimated that 600,000 people in the UK struggle with the condition; the NHS claims that at 60, around one in every 2,000 people has AMD, but by the age of 90, it affects one person in five.
There is no specific cause. However, age and lifestyle factors such as smoking, obesity, drinking alcohol, and eating a diet high in processed foods and low in nutrient-dense fruits and vegetables increase the chances of it developing.
It usually first affects people in their 50s and eventually causes the light-sensitive tissue to die off or be damaged by abnormal blood vessel growth. Currently, there is no licensed treatment for AMD, but researchers claim that metformin could be an accessible treatment option.
The new study, from the University of Liverpool and published in the BMJ, found that people aged 55 and over with diabetes who were taking metformin were 37 per cent less likely to develop intermediate AMD over five years than those not taking metformin.
They examined images of the eyes of 2,545 people who had attended the routine diabetic eye disease screening programme in Liverpool over a five-year period.
Each patient had retinal photographs taken in 2011 and again in 2016, which were graded by eye specialists using a recognised system and classified as Early AMD, Intermediate AMD, or Late AMD, the stage most likely to cause serious vision loss.
The researchers used GP records to establish which cohort members were prescribed metformin. They then compared how often AMD developed or got worse in people on the drug versus those not on it.
They concluded that in people with diabetes, taking metformin was linked to a significantly lower risk of developing intermediate AMD over 5 years.
However, it did not reduce the risk of developing early AMD or the likelihood of slow progression from early AMD to more advanced stages.
Other limitations noted by the study authors included that the metformin group was slightly younger and healthier in some respects, and that there was limited information on the exact metformin dose and how long people had been taking it.
Furthermore, there was no information about the cohort’s diet or whether they regularly took vitamin supplements, and the study results apply only to people with diabetes, not the general population.
They theorised that metformin might protect the retina due to its anti-ageing and anti-inflammatory effects. Further investigations are warranted.
Dr Nick Beare, an eye doctor who led this research, said: ‘Most people who suffer from AMD have no treatment, so this is a great breakthrough in our search for new treatments.
Dr Beare added: ‘Next, we need clinical trials to confirm these findings, as metformin could potentially preserve sight for many.’
Metformin, which has been in use for over 60 years, lowers the amount of sugar the liver pumps into the blood and helps the body respond to insulin, a hormone that regulates blood sugar levels.
It has proved to be highly versatile, showing significant promise in managing a variety of other conditions.
Other recent studies have found that metformin helped prevent acute myeloid leukaemia. This blood cancer quickly kills about four out of five patients.
Scientists first uncovered the link between the drug and anticancer benefits in experiments on mice, then confirmed the same result in humans.
Intermediate and advanced AMD affects 10-15 per cent of people over 65. This equates to 1.1 to 1.8 million people in the UK.
It is the most common cause of blindness in high-income countries, and the annual cost of AMD is estimated to be £11.1 billion in the UK.
Advanced AMD involves significant central vision loss and is classified into two types: dry and wet.
Dry AMD involves the gradual degeneration of macular cells, leading to slowly enlarging blind spots.
Wet AMD causes rapid and severe central vision loss. It is marked by abnormal, leaky blood vessels under the retina.
Research into potential new treatments for AMD is ongoing, with recent studies showing that a tiny chip implanted in the back of the eye can effectively restore vision.
What is AMD?
Age–related macular degeneration (AMD) is a painless eye condition that leads to a gradual loss of central vision.
It is the most common cause of visual impairment in the UK and the US, affecting 600,000 adults in the UK and fewer than 2 million in the US.
AMD causes central vision to blur. This leads to difficulty reading and trouble recognising faces.
It does not cause total blindness, but it can make things like reading and recognising faces difficult.
It occurs when the macula, the part of the eye responsible for central vision, stops functioning effectively.
Most people with dry AMD can experience a slight loss of central vision. AMD usually affects both eyes, but progression can vary between eyes.
It is thought to be triggered by ageing, smoking and genetics.