Inflammatory bowel diseases (IBDs) and multiple sclerosis (MS) are inflammatory diseases resulting from an interplay of genetic and environmental factors. This study aims to describe the prevalence of patients diagnosed with both conditions among those receiving hospital care in England, as well as the characteristics and healthcare resource use (HCRU) of such patients.

This study is a retrospective observational cohort study.

The study was conducted through secondary use of the English Hospital Episode Statistics (HES) Database. HES records care delivered by hospitals in England and associated diagnoses.

Patients who had a diagnosis code for either IBD or MS recorded in HES between January 2014 and May 2020 were included. Patients were classified as having each diagnosis individually or as having both diagnoses, in which case they were further categorised based on temporal occurrence.

The primary outcome was the prevalence of patients with a recorded diagnosis of either IBD, MS or both during the study period. Secondary outcome measures included patient demographic and clinical characteristics, as well as HCRU in the 6 months before and after the diagnosis of interest.

From an overall cohort of 352 698 patients, 1016 (0.3%) had both diagnoses. Among those with both, 29.8% (303) had a record of IBD first, 40.5% (411) had MS diagnosed first and 29.7% (302) had the first record of both diagnoses in the same episode. From the overall cohort, 80.9% (285 439) of patients had a single diagnosis of IBD, and 18.8% (66 243) of patients had a single diagnosis of MS.

The population with a dual diagnosis of IBD and MS is larger than previously reported and shows evidence of frequent interactions with secondary care.