x Abu Dhabi, UAESunday 23 July 2017

A clear-eyed case for systematic diabetes screening

Comparing inexpensive diabetes screening to possible life benefits makes a course of action obvious.

The case for medical screening, regardless of whether the technology and medical skills are available to effectively screen and treat a disease, is often more than a purely medical decision.

On the occasion of World Diabetes Day tomorrow, there is a particular concern about the health priorities of screening. With so many medical conditions in most countries clamouring for attention, each screening decision is strongly linked to health-care budgets - the cost of screening and the cost of treatment where disease is found. There is also the issue of demographics - who should be screened and who should have access to treatment, and on what terms?

However, the UAE presents a unique case because the health-care priorities and demographics are so clear-cut.

According to the World Health Organisation, the UAE has the second highest prevalence of diabetes in the world, second only to Nauru, a small island in the Western Pacific Ocean.

The Weqaya screening programme in Abu Dhabi run by HAAD has found that two-thirds of adult Emiratis in Abu Dhabi are overweight or obese, and 44 per cent are either diabetic or pre-diabetic.

The additional costs associated with diabetes in Abu Dhabi society alone are estimated to total Dh300 billion over the next 10 years, based on the treatment costs and economic effect of the disease.

The case for diabetes screening is therefore well established. Diabetic eye disease - such as diabetic retinopathy - is present in 50 per cent of people who have had diabetes for 10 years and 90 per cent of those with the disease for 20 years.

In fact, diabetic eye disease is the leading cause of blindness in the working-age population of many developed nations and its effects on the population of Abu Dhabi will grow in the next few decades, as the population ages.

And treatment of diabetic eye disease can reduce the progression of the disease, preventing severe visual loss or blindness.

So the case for diabetic eye screening among those who are known to have diabetes also seems clear.

But can the effect of screening be quantified?

Cost effectiveness of screening is generally regarded as the cost of screening per "true positive" detected (finding someone with the disease). Cost utility is the cost per "quality adjusted life year" - a measure of the value for money of a medical intervention.

The Liverpool diabetes group has estimated that the cost effectiveness of screening in Liverpool in the UK is about £289 (Dh1,700) - that is to say the money spent to find each diabetic patient with eye disease by screening that group is just £289; and similar results have been obtained in the United States.

There is no agreed value for the cost of blindness in any population, just a wide range of estimates. However, it is believed that in the United Kingdom the National Institute for Clinical Excellence will probably accept any intervention where the cost per "quality adjusted life year" is below £30,000 (this figure is around $50,000 in the United States). Given that screening is very cheap and treatment is relatively inexpensive, diabetic eye screening makes very good sense.

Timely intervention is able to prevent progression to severe visual loss in 90 per cent of eyes with sight-threatening retinopathy. The length of lifetime that a diabetic will spend blind depends on a number of factors including age, diabetic control and other conditions, so the years of sight saved by treatment will depend on the population demographics. But just ask the patients if they think it is worthwhile.

 

Dr Chris Canning is a consultant vitreo-retinal surgeon and medical director at Moorfields Eye Hospital Dubai