Advanced

The use of ICD codes to identify IBD subtypes and phenotypes of the Montreal classification in the Swedish National Patient Register

Shrestha, Sarita ; Olén, Ola ; Eriksson, Carl ; Everhov, Åsa H ; Myrelid, Pär ; Visuri, Isabella ; Ludvigsson, Jonas F ; Schoultz, Ida ; Montgomery, Scott and Sachs, Michael C , et al. (2020) In Scandinavian Journal of Gastroenterology
Abstract

Introduction: Whether data on International Classification of Diseases (ICD)-codes from the Swedish National Patient Register (NPR) correctly correspond to subtypes of inflammatory bowel disease (IBD) and phenotypes of the Montreal classification scheme among patients with prevalent disease is unknown.Materials and methods: We obtained information on IBD subtypes and phenotypes from the medical records of 1403 patients with known IBD who underwent biological treatment at ten Swedish hospitals and retrieved information on their IBD-associated diagnostic codes from the NPR. We used previously described algorithms to define IBD subtypes and phenotypes. Finally, we compared these register-generated subtypes and phenotypes with the... (More)

Introduction: Whether data on International Classification of Diseases (ICD)-codes from the Swedish National Patient Register (NPR) correctly correspond to subtypes of inflammatory bowel disease (IBD) and phenotypes of the Montreal classification scheme among patients with prevalent disease is unknown.Materials and methods: We obtained information on IBD subtypes and phenotypes from the medical records of 1403 patients with known IBD who underwent biological treatment at ten Swedish hospitals and retrieved information on their IBD-associated diagnostic codes from the NPR. We used previously described algorithms to define IBD subtypes and phenotypes. Finally, we compared these register-generated subtypes and phenotypes with the corresponding information from the medical records and calculated positive predictive values (PPV) with 95% confidence intervals.Results: Among patients with clinically confirmed disease and diagnostic listings of IBD in the NPR (N = 1401), the PPV was 97 (96-99)% for Crohn's disease, 98 (97-100)% for ulcerative colitis, and 8 (4-11)% for IBD-unclassified. The overall accuracy for age at diagnosis was 95% (when defined as A1, A2, or A3). Examining the validity of codes representing disease phenotype, the PPV was 36 (32-40)% for colonic Crohn's disease (L2), 61 (56-65)% for non-stricturing/non-penetrating Crohn's disease behaviour (B1) and 83 (78-87)% for perianal disease. Correspondingly, the PPV was 80 (71-89)% for proctitis (E1)/left-sided colitis (E2) in ulcerative colitis.Conclusions: Among people with known IBD, the NPR is a reliable source of data to classify most subtypes of prevalent IBD, even though misclassification commonly occurred in Crohn's disease location and behaviour and also among IBD-unclassified patients.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; ; ; and , et al. (More)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; and (Less)
author collaboration
publishing date
type
Contribution to journal
publication status
epub
subject
in
Scandinavian Journal of Gastroenterology
pages
6 pages
publisher
Taylor & Francis
external identifiers
  • pmid:32370571
  • scopus:85084438205
ISSN
0036-5521
DOI
10.1080/00365521.2020.1740778
language
English
LU publication?
no
id
172fd826-33fc-4682-92bc-27504ae66f24
date added to LUP
2020-05-12 15:22:11
date last changed
2021-01-19 03:49:13
@article{172fd826-33fc-4682-92bc-27504ae66f24,
  abstract     = {<p>Introduction: Whether data on International Classification of Diseases (ICD)-codes from the Swedish National Patient Register (NPR) correctly correspond to subtypes of inflammatory bowel disease (IBD) and phenotypes of the Montreal classification scheme among patients with prevalent disease is unknown.Materials and methods: We obtained information on IBD subtypes and phenotypes from the medical records of 1403 patients with known IBD who underwent biological treatment at ten Swedish hospitals and retrieved information on their IBD-associated diagnostic codes from the NPR. We used previously described algorithms to define IBD subtypes and phenotypes. Finally, we compared these register-generated subtypes and phenotypes with the corresponding information from the medical records and calculated positive predictive values (PPV) with 95% confidence intervals.Results: Among patients with clinically confirmed disease and diagnostic listings of IBD in the NPR (N = 1401), the PPV was 97 (96-99)% for Crohn's disease, 98 (97-100)% for ulcerative colitis, and 8 (4-11)% for IBD-unclassified. The overall accuracy for age at diagnosis was 95% (when defined as A1, A2, or A3). Examining the validity of codes representing disease phenotype, the PPV was 36 (32-40)% for colonic Crohn's disease (L2), 61 (56-65)% for non-stricturing/non-penetrating Crohn's disease behaviour (B1) and 83 (78-87)% for perianal disease. Correspondingly, the PPV was 80 (71-89)% for proctitis (E1)/left-sided colitis (E2) in ulcerative colitis.Conclusions: Among people with known IBD, the NPR is a reliable source of data to classify most subtypes of prevalent IBD, even though misclassification commonly occurred in Crohn's disease location and behaviour and also among IBD-unclassified patients.</p>},
  author       = {Shrestha, Sarita and Olén, Ola and Eriksson, Carl and Everhov, Åsa H and Myrelid, Pär and Visuri, Isabella and Ludvigsson, Jonas F and Schoultz, Ida and Montgomery, Scott and Sachs, Michael C and Halfvarson, Jonas and Olsson, Malin and Hjortswang, Henrik and Bengtsson, Jonas and Strid, Hans and Andersson, Marie and Jäghult, Susanna and Eberhardson, Michael and Nordenvall, Caroline and Björk, Jan and Fagerberg, Ulrika L and Rejler, Martin and Grip, Olof and Karling, Pontus and Block, Mattias and Angenete, Eva and Hellström, Per M and Gustavsson, Anders},
  issn         = {0036-5521},
  language     = {eng},
  month        = {05},
  publisher    = {Taylor & Francis},
  series       = {Scandinavian Journal of Gastroenterology},
  title        = {The use of ICD codes to identify IBD subtypes and phenotypes of the Montreal classification in the Swedish National Patient Register},
  url          = {http://dx.doi.org/10.1080/00365521.2020.1740778},
  doi          = {10.1080/00365521.2020.1740778},
  year         = {2020},
}