IBD prevalence: The narrative is not yet written
LAS VEGAS — Though it often seems the writing is on the wall for the incidence and prevalence of inflammatory bowel disease, an expert at Crohn’s & Colitis Congress argued that the more discovered about environmental impact and the more interventions implemented, the rising incidence and prevalence could be stemmed.
“IBD is a modern disease of modern times,” Gilaad Kaplan, MD, MPH, FRCPC, of the University of Calgary, said during his presentation.
Recent studies point toward the developed world moving into the third of four stages of disease progression. First, it emerged in the early 20th century and then incidence accelerated, a stage that developing nations are entering currently. Today, Kaplan said, the Western world is in the stage of compounding prevalence.
In a poster presented at the Congress, data showed that the incidence of IBD in Latin America is “rising very, very rapidly,” Kaplan said. While he acknowledged that greater awareness, better access to health care and improved tracking of disease all contribute to the incidence, environmental factors likely play the greatest role.
“As we are all aware in this room, probably the primary driver is that environmental exposures associated with the westernization of society is a huge factor in driving the incidence up in these regions,” Kaplan said. “As these countries look more like Canada, more like the United States, we see IBD emerge and the incidence rise.”
Unfortunately, he added, that contributing factor is less studied than genetics or the microbiome makeup.
“While our understanding of genetics and microbiome is exponentially expanding every year, I feel our understanding of environmental triggers is lagging far behind,” Kaplan said.
That leads developed nations like the United States and Canada into the era of compounding prevalence, he added.
“Even though the incidence will stabilize, the prevalence will start to accumulate quite significantly,” Kaplan said. “The reason for this is because IBD is predominantly diagnosed in young individuals. There is no cure for the disease, but the mortality is low, meaning they are going to live a long life so every year we will add patients to the base of our clinics without losing others.”
In 2018, the prevalence of IBD is 0.7% of the population, equating to roughly 270,000 Canadians living with IBD, he said. A recent forecasting model estimates that 400,000 Canadians – 1% of the population – will have IBD by 2030.
“We are already struggling today to provide great accessible and affordable care to these people. What is it going to be like with that many more people?” Kaplan asked.
In a poster presented at the Congress, researchers showed that it will be quite a while before the fourth stage of prevalence equilibrium – the threshold whereby the incidence approximates the mortality – will be reached. The incidence in 2015 was 28.7 per 100,000. The projected incidence in 2030 is 21.6 per 100,000. The equilibrium threshold would need to be 7.8 per 100,000.
Still, Kaplan ended his talk with some optimism.
“There is an inherent limitation to the data I’m showing you. It has a fundamental assumption that what’s happened to incidence in the past is what is going to happen to incidence in the future but that’s not necessarily true and it’s definitely not known,” he said.
“This narrative is yet to be written. There are many people in this room with what we do every day in our clinical capacity and our research capacity that may have the ability to rewrite this story. We potentially could develop interventions that actually drive incidence down even lower and it’s in that capacity that we could potentially reach this prevalence threshold at a much earlier stage than if we just let things be as they are.” – by Katrina Altersitz
Coward S. P104. Presented at: Crohn’s & Colitis Congress; Feb. 7-9, 2019; Las Vegas.
Coward S. Gastroenterology; 2019. doi: 10.1053/j.gastro.2019.01.002.
Kaplan G. Sp83. Presented at: Crohn’s & Colitis Congress; Feb. 7-9, 2019; Las Vegas.
Kotze PG. P105. Presented at: Crohn’s & Colitis Congress; Feb. 7-9, 2019; Las Vegas.
Disclosure: Kaplan reports acting as a consultant for AbbVie, Janssen, Pfizer and Takeda; as a speaker for AbbVie, Janssen, Pfizer and Takeda; and holds a patent with UTI Limeted Partnership.