Genetic Marker Tied to Severe Ulcerative Colitis Identified

TOPLINE:
VIENNA — Individuals with ulcerative colitis (UC) who carry the HLA-DRB1*01:03 allele are at increased risk of having a more severe disease course requiring major surgery, hospitalization, and high-dose systemic corticosteroids within 3 years of diagnosis, according to a Danish study.
METHODOLOGY:
Reliable biomarkers are lacking to identify patients with inflammatory bowel disease at greater risk for severe disease and who therefore might require intensified monitoring and treatment.
Researchers explored genetic variants associated with severe UC in patients from two Danish cohorts, whose DNA was extracted from dried blood spots and full blood, with genotyping then performed to assess the presence of human leukocyte antigen (HLA) alleles and single-nucleotide variants.
Severe UC was defined as having at least one major UC-related operation, at least two UC-related hospitalizations exceeding 2 days, and/or use of at least 5000 mg of systemic corticosteroids within 3 years of diagnosis. Patients not meeting these criteria were considered to have less severe UC and included as the comparison group.
A genome-wide association study was conducted comparing severe vs less severe UC.
TAKEAWAY:
Researchers analyzed 4491 patients with UC (mean age at diagnosis, 23 years; 53% women; 27% with severe UC) and determined that carriers of the HLA-DRB1*01:03 allele had a significantly higher risk for severe UC (odds ratio, 3.32).
Compared with noncarriers, those with this allele had an approximately sixfold increased risk of needing major surgery, a fivefold increased risk of requiring at least two hospitalizations, and a twofold increased risk for use of over 5000 mg of systemic corticosteroids within 3 years of diagnosis.
Time-to-event analysis showed that the association between carriers and disease severity extended beyond 3 years after diagnosis.
Compared with noncarriers, those with the HLA-DRB1*01:03 allele had a higher hazard ratio for time to hospitalization, major surgery, and first treatment with systemic corticosteroids.
IN PRACTICE:
“Although HLA-DRB1*01:03 is a low-frequency allele, carriers have a significantly higher risk of severe ulcerative colitis. Given the low cost of typing a single HLA allele, HLA-DRB1*01:03 could be a valuable tool for risk assessment of patients with ulcerative colitis at diagnosis,” the authors concluded.
SOURCE:
The study, with first author Marie Vibeke Vestergaard, MSc, Aalborg University, Aalborg, Denmark, was published online on October 15 in JAMA, to coincide with its presentation at United European Gastroenterology (UEG) Week 2024 in Vienna, Austria. 
LIMITATIONS:
The findings are based on a Danish population of European genetic ancestry and require validation in diverse patient cohorts with UC.
DISCLOSURES:
The study was funded by the Danish National Research Foundation, the Lundbeck Foundation, and the Novo Nordisk Foundation. The authors reported no relevant disclosures related to the study.
 
Send comments and news tips to [email protected].