(12) Validation of IBD diagnosis date and disease location in the Danish national registers using NorDIBD
Författare/Medförfattare
Linéa Bonfils [1]*, Laurits T. Dalsgaard [1]*, Gry J. Poulsen [1], Mikkel Eld [2], Tine Jess [1,3], Lone Larsen [1,3], Kristine H. Allin [1,3]*These authors contributed equally to this work
Affiliates
[1] Center for Molecular Prediction of Inflammatory Bowel Disease (PREDICT), Department of Clinical Medicine, Aalborg University, Copenhagen, Denmark[2] Department of Pathology, Aalborg University Hospital, Aalborg, Denmark[3] Department of Gastroenterology & Hepatology, Aalborg University Hospital, Aalborg, Denmark
Abstract
Background:
Inflammatory bowel disease (IBD) location is not directly recorded in the national Danish health registers. Previous studies have attempted to assess disease location from ICD-10 codes in the Danish National Patient Registry (DNPR) and showed inconsistent results. In this study we aimed to capture disease location from pathology codes in the Danish Pathology Registry (DPR) at the time of diagnosis and validate it using a regional, clinically validated cohort as the gold standard. As a prerequisite analysis we validated date of diagnosis in the DNPR, using the regional cohort as gold standard.
Methods:
We identified all patients with incident IBD in the regional North Denmark IBD cohort (NorDIBD) between 2000 and 2020. We compared their diagnosis date recorded in the DNPR to their diagnosis date recorded in the NorDIBD. Next, we inferred their disease location from recorded pathology codes in the DPR and compared to disease location as recorded in the NorDIBD.
Results:
We identified 3163 patients with incident IBD. The mean number of days between date of diagnosis in the DNPR and NorDIBD was 8 (95% CI -36, 53) days for CD and 62 (95% CI 27, 96) days for UC. Out of 1053 CD patients, we could infer the disease location for 662 (63%) patients. For colonic disease (L2) we found a sensitivity of 0.94 (95% confidence interval (CI) 0.92, 0.96), a specificity of 0.75 (95% CI 0.71, 0.79), a positive predictive value of 0.83 (95% CI 0.80, 0.86), and a negative predictive value of 0.90 (95% CI 0.87, 0.93). Out of 2110 UC patients, we could infer the disease location for 1189 (56%) patients. For ulcerative proctitis (E1), we found a sensitivity of 0.94 (95% CI 0.92, 0.96), a specificity of 0.76 (95% CI 0.73, 0.79), a positive predictive value of 0.85 (95% CI 0.83, 0.87), and a negative predictive value of 0.91 (95% CI 0.89, 0.93). Corresponding measures for ileal and ileocolonic disease location in CD (L1 and L3) and left-sided and extensive colitis in UC (E2 and E3) were low.
Conclusion:
The date of IBD diagnosis in the DNPR shows high validity. IBD location can be inferred via pathology codes for approximately 60% of patients with IBD. Colonic disease (L2) for CD and proctitis (E1) for UC shows high validity. These findings are useful for future epidemiological studies in the field of IBD.