People with a higher genetic risk of inflammatory bowel disease (IBD) may also be more likely to develop more severe forms of the condition, according to a Danish study of more than 8,000 patients.
The research, published in Gastoenterology, suggests that genetic testing could eventually help physicians predict how aggressively IBD will progress after diagnosis, allowing care teams to tailor monitoring and treatment earlier in the disease course.
IBD – including Crohn’s disease and ulcerative colitis – can lead to repeated hospitalizations, surgery, and lifelong medication. However, the severity of the disease varies widely between patients, making it difficult for clinicians to predict who will develop complications.
To investigate whether genetics might help explain these differences, researchers analyzed data from Danish health registries and genetic databases covering 3,732 people with Crohn’s disease and 4,535 with ulcerative colitis. Using genome-wide data, the team calculated “polygenic scores,” which estimate a person’s inherited risk of developing IBD based on the combined effect of hundreds of genetic variants.
The results showed a clear pattern: patients with higher genetic risk scores were more likely to experience more severe disease. Compared with those with lower scores, patients with higher genetic risk had increased levels of inflammatory markers at diagnosis, including fecal calprotectin and C-reactive protein, and lower hemoglobin levels – signs linked to more active disease.
Patients with higher genetic risk were also more likely to need hospitalization, surgery, and intensive treatment such as corticosteroids, immunomodulators, or biologic drugs within the first few years after diagnosis.
In practical terms, this means that genetics may influence not only whether someone develops IBD, but also how severe the disease becomes. The association was particularly strong for ulcerative colitis. For Crohn’s disease, the link appeared to be partly explained by how much of the intestine was affected.
Although genetic risk scores are not yet used routinely in clinical care, the findings highlight their potential value in future patient management. In the future, such tools could help physicians identify high-risk patients soon after diagnosis, enabling earlier use of advanced therapies and closer follow-up to prevent complications and improve long-term quality of life.
Newsletters
Receive the latest pathologist news, personalities, education, and career development – weekly to your inbox.
