The pros are starting to outweigh the cons with growing awareness of underdiagnosis, delayed diagnosis and asymptomatic disease.
In September Italy’s parliament voted for nationwide screening to detect type 1 diabetes and coeliac disease in children aged one to 17, starting this year.
Australia is still using a case-finding approach, but one coeliac expert says this strategy may be missing up to 80% of cases.
Italy’s decision followed a screening trial led by Professor Elena Lionetti of the Marche Polytechnic University in Ancona, which found a prevalence of 1.65% in a sample of almost 4500 children. This was higher than expected and represented a doubling of coeliac prevalence in Italy in 25 years.
Associate Professor Jason Tye-Din, a gastroenterologist at Royal Melbourne Hospital who heads the Coeliac Research Lab at the Walter and Eliza Hall Institute, said global prevalence was about 1.4%, with some marked but as yet unexplained geographical differences.
He said Australia’s current strategy, leaving it up to GPs to look for suggestive symptoms, family history and a history of autoimmune diseases, left a high proportion of cases undetected as the classic symptoms were an unreliable guide.
“What we know is that this approach is an ineffective way to detect coeliac disease,” he told Gut Republic.
“From population screening studies, we know 50-80% of people detected with coeliac disease don’t know they have it, and that’s partly because symptoms are a poor guide as to the presence of coeliac disease.
“Even if a doctor is highly motivated and closely follows the NICE guidelines for every patient that walks in through their door, they will still miss most cases of coeliac disease.”
The symptom list includes not only abdominal pain, diarrhoea, bloating, cramps, altered bowel habit and weight loss, but also nonspecific non-GI symptoms such as lethargy, fertility problems and osteoporosis, which aren’t widely recognised as linked to coeliac disease.
The argument against screening, Professor Tye-Din said, was that a seemingly healthy patient might go for screening, be found to have the disease and be put on a difficult and lifelong gluten-free diet.
“Will that improve their health and quality of life? Or is it potentially making their life worse because they now have a restrictive diet they need to follow for the rest of their life, even though they were never feeling unwell to begin with?” he said.
“While a valid concern, the pendulum is swinging in favour of population screening. Studies have shown that there’s very high rates of coeliac disease in the paediatric population [2.4% in the Colorado ASK study], that 90% of these children do not have a family history of coeliac and 70% don’t report classical symptoms. A lot of people don’t realise they have symptoms, but when they’re diagnosed and treated, they feel better.”
Being asymptomatic when exposed to gluten does not protect a patient from complications such as osteoporosis and lymphoma, he said.
“Asymptomatic doesn’t mean a patient is well. There can be ‘hidden’ issues such as nutrient deficiencies and reduced bone density,” he said.
“And not everyone who claims they’re asymptomatic is truly asymptomatic.
“People often accept their symptoms as normal without appreciating they are not. It’s only after they get diagnosed and treated with a gluten-free diet that they suddenly realise, ‘Oh my God! I feel amazing, I didn’t realise that I was actually tired.’”
The median age of diagnosis here is 40, but onset is frequently before the age of 10.
“That tells us that many people are living with low-grade symptoms and putting up with them for a long time before they get diagnosed,” said Professor Tye-Din.
Childhood is a good time to catch coeliac as dietary adherence can be a lot better, he said.
In 2017 a review by the US Preventive Services Task Force found inadequate evidence to assess the balance of harms and benefits of screening for CD.
The Italian scheme is likely to provide good evidence, but Professor Tye-Din said it would take a long time.
“I think it’s important to have these conversations now and start to accrue the evidence,” he said.
“Population screening may be an important step forward to detect disease before it has a chance to cause irreparable harm later in life and hopefully improve our patient outcomes.
“It starts with just a simple blood test.”
