Epidemiology of inflammatory bowel disease in the UK

Study type
Protocol
Date of Approval
Study reference ID
21_000731
Lay Summary

Inflammatory bowel disease, known as “IBD”, is characterized by inflammation of the digestive system that severely impacts the quality of life of the patients suffering from it. IBD poses an increasing health and economic burden in the UK, which compared to other countries has one of the highest proportions of IBD patients in its population. From a public health perspective, knowing how many new patients are diagnosed yearly, and their characteristics, are key for healthcare authorities and practitioners to determine resource allocation for IBD care in the UK.

The proposed study will provide up-to-date estimates of the number of patients currently living with IBD and their characteristics, including other medical conditions these patients may also suffer. We will estimate the number of patients newly diagnosed with IBD since 2005 each year, which are key to understanding the burden of IBD in the UK. To estimate these figures, we will use both CPRD GOLD and Aurum (which has greater patient coverage). Of note and to our knowledge, this study will be the first epidemiological study of IBD using Aurum. Also, patients with IBD are known to suffer more from heart disease, blood clots and serious infections. We will therefore also examine the risk factors for these outcomes (such as diabetes or smoking) among patients with IBD.

The evidence from the proposed study will support healthcare practitioners and public health authorities to prepare for the medical and socioeconomic challenges posed by IBD in the UK during the beginning of the new decade.

Technical Summary

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal (GI) tract that is non-infectious and progressive. IBD poses an increasing burden globally and in the UK, which has one of the highest prevalence of IBD in the world. Epidemiological measures of IBD vary substantially not only globally, but also in the UK, which could be attributed to inconsistencies in case definitions across studies. Further, the COVID pandemic has negatively impacted the diagnoses of many infectious and chronic diseases, including IBD, which directly impacts incidence and prevalence estimates. From a public health perspective, obtaining valid and updated epidemiologic measures are key for adequately determining resource allocation for IBD care, prevention and management in the UK.

Therefore, this study will estimate the incidence and prevalence of IBD. Yearly, and overall, estimates of incidence will be calculated since 2005, while the prevalence will be estimated at the cross-sectional date (31/12/2020). Results will be standardised to the UK population (or England and Wales for Aurum). Patient characteristics including comorbidities, comedication and demographics will be estimated at the date of diagnosis (incidence study) and at the cross-sectional date (prevalence study). This study will also provide the distribution of risk factors for cardiovascular events, venous thromboembolism and serious and opportunistic infections given that IBD may be associated with these harmful outcomes. The study will be performed in both CPRD GOLD and Aurum, and will include HES APC and patient-level Townsend linkages. This will be the first epidemiological study of IBD in Aurum and thus will benefit from the wider coverage of the EMIS network.

The evidence to be generated from the proposed study will support healthcare practitioners and public health authorities to prepare for the medical and socioeconomic challenges posed by IBD in the UK during the beginning of the new decade.

Health Outcomes to be Measured

Incidence of inflammatory bowel disease (IBD), ulcerative colitis (UC) and Crohn’s disease (CD) in the UK population by year, by age and by gender since 2005, using medical codes from CPRD GOLD and Aurum; prevalence of inflammatory bowel disease (IBD), ulcerative colitis (UC) and Crohn’s disease (CD) in the UK population by age and by gender in 2020, using medical codes from CPRD GOLD and Aurum. Examination of patient characteristics, comorbid conditions, and history of medications.

Collaborators

Agustin Cerani - Chief Investigator - Galapagos ( GLPG )
Agustin Cerani - Corresponding Applicant - Galapagos ( GLPG )
Ali Charkhi - Collaborator - Galapagos ( GLPG )
Andrew Maguire - Collaborator - EpiFocus Ltd
Claus Andersen - Collaborator - Galapagos ( GLPG )
Hari Patel - Collaborator - Galapagos ( GLPG )
Mona Khalid - Collaborator - Galapagos ( GLPG )
Raymond Schlienger - Collaborator - Galapagos ( GLPG )

Linkages

HES Admitted Patient Care;Patient Level Townsend Index