Rising Prevalence of Ulcerative Colitis

A progressing disease raises concerns

A new study conducted by researchers from the University of New South Wales (UNSW) has found that the number of Australians suffering from inflammatory bowel disease (IBD) is on the rise. The study, which analysed data from more than 11 million patients, showed that the prevalence of IBD was 653 cases per 100,000 people, while Crohn’s disease (CD) was 306 cases per 100,000 and ulcerative colitis (UC) was 334 cases per 100,000. This prevalence is much higher than previously reported in regional population-based studies in Australia, and experts are wondering why.

There are well-known variations in prevalence regarding age group, indigenous status, smoking status, socioeconomic status, and state/territory. CD is more prevalent among females than males, while the prevalence of UC is similar for both sexes. Through the UNSW study, being male was associated with a lower risk of CD but a greater risk of UC. The study also found that Aboriginal and/or Torres Strait Islanders have a lower risk of developing IBD, which is consistent with other reports that have demonstrated a lower risk of IBD in Indigenous populations.

Ulcerative colitis (UC) is a chronic inflammatory disorder affecting the colonic mucosa. The prevalence of UC is estimated to be between 249 and 263 per 100,000. Treatment modalities differ according to the extent of involvement of the bowel and the location of inflammation (proximal or distal), which determine the severity of the disease. Tumour necrosis factor inhibitors (TNFi) including adalimumab (ADA), infliximab (IFX), and golimumab have been approved for use in patients with moderately to severely active UC who fail to respond to conventional therapies such as 5-aminosalicylic acid, corticosteroids, or mesalazine.

What is leading to this increase?

Analyses have indicated global increasing incidence of UC between 1950-2010, followed by stabilisation/reduction of incidence rates between 1990-2016 in Europe and North America. However, the incidence of UC continues to increase in newly industrialised countries, which is considered to be linked to the westernisation of diets and environments. Despite stabilisation of incidence in western countries, prevalence continues to increase. A forecast of the global burden of IBD between 2015 and 2025 predicted exponential growth of the number of patients, due to increased rates of diagnosis and low mortality. 

Regional differences in UC incidence and prevalence have also been observed. Some areas of North America and Europe, such as Scandinavia and Canada, have reported higher rates of UC compared to other regions. However, the reasons for these differences are not fully understood and may be influenced by a combination of genetic, environmental, and lifestyle factors.

What does the future hold?

Certain clinical factors have also been linked to poor prognostic outcomes in UC. Disease extent, severity, and duration at diagnosis have been identified as important predictors of disease course. Patients with extensive colitis (involving the entire colon) tend to have a more severe disease course compared to those with limited colitis (affecting only a portion of the colon). Additionally, patients with more severe disease activity at diagnosis, as assessed by clinical and endoscopic criteria, are at higher risk of poor outcomes. Longer disease duration at diagnosis is also associated with a higher risk of complications and poorer prognosis in UC.

Genetic factors may also influence the prognosis of UC. A family history of inflammatory bowel disease (IBD), including UC, has been associated with increased disease severity and poorer outcomes. Certain genetic variants have been identified as risk factors for UC, and their presence may indicate a higher risk of a severe disease course.

Early intervention is key

Improving prognosis starts with early intervention and modification of risk factors associated with poorer outcomes. A few recommendations from the UNSW study include:

1. Quit smoking – Smoking cessation is the first factor to help achieve remission much faster. The faster remission is achieved, the better the disease course  and long term outcomes.
2. Medication compliance – Beginning or continuing recommended medications is important to stable disease and tracking of changes. Providing support to patients who may feel worried or concerned with medications and changes to their health status should be monitored closely. 
3. Maintaining a healthy diet – Arranging a dietician review is important at the time of diagnosis to help avoid dietary triggers and make sure the risk of malnutrition is limited. Discuss the role of Team Care Arrangements in the short and long term management of patient outcomes. 
4. Reducing stress – If you think that stress or mental health may play a significant part in the disease progression, arrange psychologist input to look at ways of improving mental health and well-being. 

Richardson, J. et al. (2018) “The increasing global incidence of ulcerative colitis; implications for the economic burden of ulcerative colitis,” Value in Health, 21. Available at: https://doi.org/10.1016/j.jval.2018.04.556.