The time to inflammatory bowel disease diagnosis for patients presenting with abdominal symptoms in primary care and its association with emergency hospital admissions and surgery: a retrospective cohort study

Background: Patients with inflammatory bowel disease (IBD) presenting to primary care may experience diagnostic delays. We aimed to evaluate this and assess whether time to diagnosis is associated with clinical outcomes.

Methods: A retrospective cohort study using English primary care data from 1st January 2010 to 31st December 2019 linked to hospital admission data was undertaken. Patients were followed from the first IBD related presentation in primary care to IBD diagnosis. Associations of time to diagnosis exceeding a year were assessed using a Robust Poisson regression model. Associations between time to diagnosis and IBD-related emergency hospital admissions and surgery were assessed using Poisson and Cox proportional hazards models respectively.

Results: Of 28,092 IBD patients, 60% had ulcerative colitis (UC) and 40% had Crohn’s disease (CD). Median age was 43 years (interquartile range 30-58) and 51.9% were female. Median time to diagnosis was 15.6 months (IQR 4.3- 28.1). Factors associated with more than a year to diagnosis included: female sex (adjusted risk ratio 1.23, 95% CI 1.21-1.26), older age (1.05, 1.01-1.10, comparing >70 years to 18-30), obesity (1.03, 1.00-1.06), smoking (1.05, 1.02-1.08), CD compared to UC (1.13, 1.11-1.16) and a faecal calprotectin over 500 μg/g (0.89(0.82-0.95)). The highest quartile of time to diagnosis compared to the lowest was associated with IBD-related emergency admissions (incidence rate ratio 1.06,1.01-1.11).

Conclusion: Longer times to IBD diagnoses were associated with being female, advanced age, obesity, smoking, and Crohn’s disease. More IBD related emergency admissions were observed in patients with a prolonged time to diagnosis.