Short summary

The Danish National Patient Registry (LPR) is used in clinical epidemiological studies in IBD and therefore it is important that the diagnosis in the LPR correspond with reality. The purpose of this study is to validate the IBD diagnosis codes in LPR for patients with suspected inflammatory bowel disease, Crohns disease (CD) and ulcerative colitis (UC). Patients' records are reviewed and it is determined whether the disease and localisation correspond with the information from LPR.

Rationale

IBD is a multifactorial disease in which an inflammatory response to environmental and microbial factors occurs in the bowel of people who are genetically predisposed to the disease. Epidemiological studies have shown that IBD patients as a group have no increased risk of intestinal cancer, but some subgroups of IBD patients do have a higher risk of cancer than the general population. With the current plans to create the so-called "research engine" at SSI the availability and dissemination of epidemiological studies in IBD is expected to improve in the years to come. In order to trust the results generated from epidemiological studies one has to know whether the diagnoses in LPR, which the studies are based on, are truly corresponding with reality. The purpose of this study is to validate the IBD diagnosis codes in LPR given to patients with suspected inflammatory disease.

Description of the cohort

Patients with an IBD diagnosis in LPR are chosen because they were either a part of the EPIC-IBD cohort ("Kost, Kræft og Helbred" cohorte and subsequently developed IBD (EPIC-IBD)) or the IBD twin cohort.

Data and biological material

CPR-numbers and diagnosis codes are collected from the Danish National Patient Registry (LPR).

Patients' records are retrieved and reviewed using a prepared questionnaire.

Data is collected about localisation and behaviour of the disease among newly diagnosed patients, change of diagnosis and the distribution and change in smoking status among patients.

Collaborating researchers and departments

Institute for Regional Health Research, Faculty of Health Sciences, University of Southern Denmark

• Clinical Associate Professor and Head Supervisor Vibeke Andersen, MD, PhD
• Project Supervisor Frederik Trier Møller, PhD

OPEN Odense Patient data Explorative Network, Odense University Hospital

• Pre-graduate Research Student Camilla Rye
• Project Supervisor Katrine Hass Rubin
• Associate Professor, PhD, MHS

Department of Epidemiological Research, Statens Serums Institut

• Project supervisor and Professor Tine Jess, MD, DMSc

Publications associated with the project

Rye C, Rubin KH, Møller FT, Julsgaard M, Jess T, Andersen V, "Positive predictive value of diagnostic codes for inflammatory bowel disease in the Danish National Patient Registry among individuals 50+ years, using patient records as reference". Clin Epidemiol. 2021;13:335-344