Clinical Epidemiology (Apr 2022)
Identification of Childhood-Onset Inflammatory Bowel Disease in Swedish Healthcare Registers: A Validation Study
Abstract
Natalia Mouratidou,1,2 Petter Malmborg,2,3 Jacob Järås,2 Vignir Sigurdsson,4 Olof Sandström,5 Ulrika L Fagerberg,6,7 Gabriella Bröms,2,8 Jonas F Ludvigsson,9,10 Ola Olén2,3 On behalf of the SWIBREG Study Group1Astrid Lindgren Children’s Hospital, Karolinska University Hospital, Stockholm, Sweden; 2Division of Clinical Epidemiology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden; 3Sachs’ Children and Youth Hospital, Södersjukhuset, Stockholm, Sweden; 4Department of Pediatrics, Institute of Clinical Sciences, The Sahlgrenska Academy at University of Gothenburg and Queen Silvia’s Children’s Hospital, Gothenburg, Sweden; 5Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden; 6Department of Women´s and Children´s Health, Karolinska Institutet, Stockholm, Sweden; 7Department of Pediatrics, Centre for Clinical Research, Västmanland Hospital, Västerås, Uppsala University, Västerås, Sweden; 8Gastroenterology, Danderyds Hospital, Stockholm, Sweden; 9Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Solna, Sweden; 10Department of Pediatrics, Örebro University Hospital, Örebro, SwedenCorrespondence: Natalia Mouratidou, Astrid Lindgren Children’s Hospital, Karolinska University Hospital, Stockholm, Sweden, Tel +46708108338, Fax +46812393251, Email [email protected]: The Swedish National Patient Register (NPR) is often used in observational studies of childhood-onset inflammatory bowel disease (IBD) (< 18 years of age) and its subtypes, but the validity of previously used register-based algorithms for capturing childhood-onset IBD has never been examined.Methods: We identified a random sample of 233 individuals with at least two first ever diagnostic listings of IBD in the NPR between 2002 and 2014. We calculated the test characteristics for different register-based definitions of IBD and its subtypes using the Copenhagen criteria and the revised Porto criteria as gold standard, both based on medical chart review. We made assumptions of the occurrence of undiagnosed IBD in the general child population based on available literature.Results: Out of 233 individuals with at least two diagnostic listings of IBD, 216 had true IBD, resulting in a positive predictive value (PPV) = 93% (95% confidence interval (CI) 89– 96), sensitivity = 88% (95% CI 83– 92), specificity = 100% (95% CI 100– 100), and negative predictive value (NPV) = 100% (95% CI 100– 100). The PPV for the NPR-based definitions of IBD subtypes at time of first IBD diagnosis and at end of follow-up were 78% (95% CI 69– 86) and 88% (95% CI 80– 94), respectively, for Crohn’s disease and 74% (95% CI 63– 83) and 71% (95% CI 60– 80), respectively, for ulcerative colitis.Conclusion: The validity of register-based definitions of childhood-onset IBD in the Swedish NPR is high and can be used to identify patients in observational research.Keywords: health administrative data, Crohn’s disease, ulcerative colitis, disease progression, diagnostic delay
