Crohn’s disease can be detected in blood eight years before symptoms show, finds study

Signs of the debilitating bowel condition Crohn’s disease can be detected in routine blood tests up to eight years before the onset of symptoms, and up to three years before a diagnosis of ulcerative colitis. The discovery suggests that early stages of inflammatory bowel diseases may begin far earlier than previously assumed, and may eventually enable doctors to intervene before severe damage occurs.

Crohn’s disease and ulcerative colitis are inflammatory bowel diseases (IBD) that affect more than 500,000 people in the UK alone. They are caused by the immune system mistakenly attacking the gut, resulting in painful sores, inflammation and symptoms such as abdominal pain and diarrhoea.

“These conditions typically affect young people at a time when they are trying to finish their education and have relationships and hold jobs down, and they can be devastating,” said Dr James Lee, a gastroenterologist at the Crick Institute in London, who led the research. “Part of the reason we did this study is because there are a proportion of people who already have quite established damage to the bowel at the time of diagnosis.”

Some of them may immediately require life-changing surgery, such as a stoma – a surgically made hole that allows body waste to be removed from the body through a colostomy bag.

Because this sort of damage takes time to accumulate, researchers have long-suspected that there must be a pre-clinical phase to the disease, where damage is occurring but people aren’t experiencing symptoms – raising the possibility that such changes might be detectable in the blood.

To investigate, Lee and colleagues turned to a database of Danish electronic health records. They scrutinised standard blood tests performed on 20,000 people with IBD in the 10 years prior to their diagnosis, comparing them with a further 4.6 million people without IBD.

Their results, published in Cell Reports Medicine, identified subtle changes in various minerals, blood cells and proteins associated with inflammation up to eight years before a diagnosis of Crohn’s disease, and three years for ulcerative colitis.

“This tells us that the origins of these diseases are happening much earlier than we ever thought they were, which could give us a huge window of opportunity to intervene with lifestyle modifications or getting people on to effective treatment much, much earlier. We hope that we could then avoid people needing to go straight for a big operation at the time of diagnosis,” Lee said.

Most of these changes would not individually have been flagged as cause for concern because they were within normal ranges – the pattern was only detected by using an algorithm to trawl through a huge dataset of patient records.

The next step is to further refine the algorithm to see if this improves its ability to identify who is at risk of developing IBD in the future, and to investigate whether treatment or prevention can reduce this risk.

“Anything that could potentially speed up the process of getting an accurate diagnosis is a hugely positive step in the right direction,” said Sarah Sleet, CEO of Crohn’s & Colitis UK.

The Guardian