The time to IBD diagnosis for patients presenting with abdominal symptoms in primary care: a retrospective cohort study

Background

Making an Inflammatory bowel disease (IBD) diagnosis in primary care can be challenging. Symptoms may mimic more common conditions such as irritable bowel syndrome or haemorrhoids, leading to diagnostic delays. Such delays may result in more complex treatment or surgery. This study aims to quantify the time to IBD diagnosis and examines associations with patient characteristics and faecal calprotectin (FC) testing.

Methods

Retrospective cohort study conducted using Clinical Practice Research Datalink (CPRD AURUM) from 1st Jan 2010 to 31st Dec 2019. Patients were followed from first presentation with symptoms, signs, test results or alternative diagnosis potentially related to IBD in primary care to IBD diagnosis. The association between patient level factors and FC with the time to IBD diagnosis were examined using logistic regression analysis. Changes in time to IBD diagnosis over the 10 year study period were also examined.

Results

28,809 incident IBD patients were identified: 17,231 (59.8%) ulcerative colitis (UC) and 11,578 (40.2%) Crohn’s disease (CD). Median age was 43.6 (IQR 30.2–59.0) years and 51.8% were female. Median time to diagnosis was 18 (IQR 5.3- 28.8) months; UC 15.6 (3.6–28.8) months and CD 19.2 (7.2–30.0) months. Factors associated with over 12 months to IBD diagnosis included: female (Odds Ratio 1.62 (95%CI 1.54–1.70)); Black ethnicity (1.49 (1.22–1.82)); South Asian ethnicity (1.43 (1.28–1.58); age compared to 18–30 years (60–70 (1.14 (1.03–1.25) and >70 (1.25 (1.12–1.39)); obesity (1.12 (1.04–1.21)); current smoking (1.11 (1.04–1.18)); lowest socioeconomic status (1.16 (1.07–1.26); anxiety (1.16 (1.07–1.25)); depression ((1.18 (1.10–1.26)); NSAID (1.52 (1.38–1.67)); loperamide (1.47 (1.24–1.75)); increasing comorbidity - Charlson score >2 (1.44 (1.31–1.60)); and CD rather than UC (1.33 (1.27–1.40)). 11% of IBD patients had FC testing. Time to diagnosis from FC date was median 3.6 (IQR 1.2- 8.4) months. A high FC level was associated with a shorter time to IBD diagnosis (<12 months): 500–1000 ((0.79 (0.67–0.91)); >1000 ((0.61(0.51–0.72)). Time to IBD diagnosis over the study period: median 16.3 (IQR 4.5–28.4) months in 2010–2011 compared to 18 (5.4--28.8) months in 2018–2019 (p=0.003).

Conclusion

There has been no improvement in time to diagnosis in IBD between 2010 and 2019. Longer times to diagnosis were associated with females, minority ethnicities, increasing age, more comorbidity, deprivation, obesity, anxiety, depression, NSAID and loperamide use and Crohn’s disease.