Inflammatory bowel diseases (IBD) include the conditions of ulcerative colitis and Crohn’s disease. Making a diagnosis of IBD can be challenging as the symptoms can be confused with more common conditions like irritable bowel syndrome. This can lead to prolonged delays in the diagnosis of IBD, which is associated with the need for more complex treatment or surgery.
We will look at anonymised electronic health records, held within a secure national database, to examine time from first presentation with symptoms, signs, blood and stool tests to IBD diagnosis. We will look if factors such as age, ethnic group, weight, smoking status and co-existing health conditions has an influence on the time to IBD diagnosis. We will examine the time to diagnosis of IBD and its impact on the need for emergency hospital admissions and surgery for IBD.
Understanding the symptoms, signs, blood markers and patient characteristics associated with time to IBD diagnosis and its impact on hospital admissions may help to develop interventions and design health services tailored to reduce diagnostic pathway length. This work will inform a follow up study to develop a IBD decision tool for GPs so that IBD patients can be recognised more easily and referred on to hospital for diagnosis and treatment.
We will undertake a retrospective open cohort study of individuals with an incident diagnosis of inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn’s disease) identified through SNOMED CT codes in primary care records in CPRD Aurum from 1st Jan 2010 to 31st Dec 2019.
The study will be divided into two parts.
Part 1:
Patients will be followed retrospectively from the date on which they were diagnosed with IBD to when they first present with symptoms, signs or test results potentially related to IBD in primary care (index date). Adults aged 18 years and older at the index date and registered with a primary care practice for at least one year before the index date will be included. The primary outcome is the time from the index date to IBD diagnosis. We will assess the association between patient level factors and the time to diagnosis using linear regression. We will also assess whether the time to diagnosis has changed over the 10 year study period.
Part 2:
In the subset of CPRD Aurum patients with linked Hospital Episode Statistics (HES) data we will examine the association between the time to diagnosis and clinical outcomes, including IBD-related emergency hospital admissions and IBD-related surgery.
Cox proportional hazards models will be used to assess the association between the time to diagnosis and the incidence of IBD-related surgery. Poisson regression models will be used to assess the association between time to diagnosis and IBD-related emergency hospital admissions.
By examining time to diagnosis and its impact on patients with IBD and their management, we will be able to assess whether there is a need for active case finding and guide referral pathway redesign to facilitate prompt diagnosis and management.
Part 1:
(i) Time from the initial presentation with IBD-related symptoms, signs and test results in primary care to the diagnosis of IBD (“time to diagnosis”). This will be assessed for IBD as a whole and then separately for ulcerative colitis and Crohn’s disease.
(ii) Mean time to diagnosis per year during the study period.
(iii) The association between patient level factors and time to diagnosis.
Part 2
(i) IBD-related emergency hospital admissions.
(ii) IBD-related surgical procedures.
Shamil Haroon - Chief Investigator - University of Birmingham
Nosheen Umar - Corresponding Applicant - University of Birmingham
Dawit Zemedikun - Collaborator - University of Birmingham
Joht Singh Chandan - Collaborator - University of Birmingham
Krishnarajah Nirantharakumar - Collaborator - University of Birmingham
Nicola Adderley - Collaborator - University of Birmingham
Nigel Trudgill - Collaborator - Sandwell and West Birmingham Hospitals NHS Trust
Shamil Haroon - Collaborator - University of Birmingham
HES Admitted Patient Care;Patient Level Index of Multiple Deprivation;Practice Level Townsend Index