Introduction

This concept provides a definition of inflammatory bowel disease (IBD), some background information - a literature review - describing how IBD has been defined in various research prior to 2010 conducted with administrative data, and a validated algorithm for IBD developed in 1999 at the University of Manitoba. The concept also provides examples of research publications where the IBD algorithm has been used, both in Deliverables from the Manitoba Centre for Health Policy (MCHP) and in journal articles from other researchers.

Definition of Inflammatory Bowel Disease (IBD)

IBD is a group of disorders characterized by inflammation of intestines (i.e., the intestines become red and swollen). The most common inflammatory bowel diseases are CD and UC. Crohn's disease is a chronic autoimmune disease that can affect any part of the gastrointestinal tract but most commonly occurs in the ileum (the area where the small and large intestine meet). Colitis is an inflammation of the large intestine that is caused by many different disease processes, including acute and chronic infections, primary inflammatory disorders (ulcerative colitis, Crohn's colitis, lymphocytic and collagenous colitis), lack of blood flow (ischemic colitis), and history of radiation to the large bowel. Source: See MedlinePlus® - Health Topics - Crohn's Disease and MedlinePlus® - Health Topics - Ulcerative Colitis for more information.

Background Information - Literature Review of IBD

Table 1 summarizes seven studies, published prior to 2010, that use administrative data to ascertain cases of IBD. The author, data source, diagnosis codes, algorithms, study cohort, validation methodology, and the purpose of study are described in Table 1. Full reference information for the studies listed in Table 1 are available in the References section below.

A Validated Inflammatory Bowel Disease (IBD) Algorithm

In Bernstein CN, et al. (1999) the aim of this study was to assess the accuracy and utility of administrative health data in identifying persons with inflammatory bowel disease on a population basis and to determine the incidence and prevalence of this disease in the Canadian province of Manitoba.

All the ICD-9-CM diagnostic codes from medical services/physician claims data and hospital discharge abstracts data were searched for diagnoses of Crohn's disease (CD) or ulcerative colitis (UC) between April 1, 1984 and March 31, 1995. Individuals with at least one diagnosis of CD or UC (n=10,451) were found. Of these individuals, Bernstein et al. (1999) selected those with at least three IBD medical contacts occurring between 1984 and 1992 and those with at least one IBD medical contact after 1993 to study further using a self-administered questionnaire (n=5182). Chart reviews were randomly completed among those individuals who responded to the questionnaire and gave written consent (n=2725).

Based on findings from the medical contact search, questionnaire responses, and medical chart review, Bernstein et al. (1999) statistically analyzed several different algorithms varying in the number of records with a CD and UC diagnosis required, over a varying amount of time as an individual registered with Manitoba Health. The algorithms were validated by comparing the identified cases of IBD from the medical services/physician claims and hospital discharge abstracts data with the self-reported information and medical chart information. This comparison yielded the following algorithm with a high degree of sensitivity and specificity (approximately 90%) to classify individuals as having CD, UC or no IBD using the administrative health data.

The ICD-10-CA codes, available in the Manitoba hospital data beginning on April 1, 2004, have been added to the original algorithm presented below.

Crohn's Disease (CD)


• For an individual registered with Manitoba Health for at least two years, they were considered to have CD if they had five or more hospitalizations or physician claims combined, with any ICD-9-CM diagnosis code = 555 or ICD-10-CA diagnosis code = K50.
  
  
• For an individual registered with Manitoba Health for less than two years, they were considered to have CD if they had three or more hospitalizations or physician claims combined, with any ICD-9-CM diagnosis code = 555 or ICD-10-CA diagnosis code = K50.

Ulcerative Colitis (UC)


• For an individual registered with Manitoba Health for at least two years, they were considered to have UC if they had five or more hospitalizations or physician claims combined, with any ICD-9-CM diagnosis code = 556 or ICD-10-CA diagnosis code = K51.
  
  
• For an individual registered with Manitoba Health for less than two years, they were considered to have UC if they had three or more hospitalizations or physician claims combined, with any ICD-9-CM diagnosis code = 556 or ICD-10-CA diagnosis code = K51.

No IBD


• An individual was considered to have no IBD if they did not have any medical contact with a diagnosis related to IBD.

If an individual had records that satisfied the criteria for both CD and UC, the nine most recent medical contacts were considered and the majority diagnosis was used.

University of Manitoba Inflammatory Bowel Disease Epidemiology Database (UMIBDED)

This algorithm led to the development of a population-based database of IBD, known as the University of Manitoba Inflammatory Bowel Disease Epidemiology Database (UMIBDED). This database is updated on a regular basis as new data becomes available.

MCHP Deliverables Using Inflammatory Bowel Disease (IBD) Algorithm

The following describes how the IBD algorithm is used in MCHP Deliverables, with links to the results presented in the publications.

1. Fransoo R, et al. (2005)

Fransoo R, et al. (2005) analyzed the percentage of Manitobans with CD or UC (termed IBD treatment prevalence), with administrative health data using the same definition as Bernstein et al. (1999) because the algorithm provided a high degree of sensitivity and specificity. A case of IBD was defined as having at least 5 diagnoses of CD or UC, based on hospital discharge abstracts and medical services/physician claims data (ICD-9-CM codes 555 or 556, respectively), between 1994/95 and 2003/04, provided that the individual had been registered with Manitoba Health for two years or more. For situations in which an individual had been registered with Manitoba Health for less than two years, only three diagnoses of CD or UC, with the above ICD codes, were required for identification as an IBD case.

For more information on IBD treatment prevalence , see 3.8 Inflammatory Bowel Disease (IBD) Treatment Prevalence (Crohn’s and Colitis) reported and discussed in this Deliverable.

2. Raymond C, et al. (2010)

Over a ten year period (1997/98-2008/09), Raymond C, et al. (2010) assessed the use of tumor necrosis factor (TNF) alpha inhibitors in adults with IBD. An individual was considered to have IBD if he/she had at least one hospital discharge abstract or medical services/physician claim record with an ICD-9-CM code 555 or 556 AND/OR ICD-10-CA code K50 or K51.

For more information on how biologic agents were used in IBD treatment, see the discussion and graphs in Chapter 5: Biologic Agents reported in this Deliverable.

3. Lix L, et al. (2021)

In Lix L, et al. (2021) an IBD sub-group was selected using the following case definition: individuals had to have at least one day of health insurance coverage prior to the index date in order to be included in the IBD sub-group. The IBD case definition is:


• For an individual with at least two years of health insurance coverage on or before the index date, that individual is considered to be an IBD case if he/she had five or more hospital discharge abstracts or physician billing claims with a relevant ICD diagnosis code (in any diagnosis position in hospital discharge abstracts);
  
• For an individual with less than two years of health insurance coverage on or before the index date, that individual is considered to be an IBD case if he/she had three or more hospital discharge abstracts or physician billing claims with a relevant ICD diagnosis code (in any diagnosis position in hospital discharge abstracts);
  
• The relevant ICD diagnosis codes were ICD-9-CM 555 or 556, or ICD-10-CA K50 or K51.

For more information on the IBD cohort characteristics and findings about this group, please open the Gastrointestinal Endoscopy (GIE) Utilization in Manitoba Deliverable and search on the term IBD.

Other Research Using Inflammatory Bowel Disease (IBD) Algorithms

The University of Manitoba IBD Epidemiology Database (UMIBDED) has been used in numerous studies to analyze a variety of topics related to IBD. The following is a selection of other publications by Bernstein CN, et al. that have used the UMIBDED database. Links to the Reference section below are provided for each reference. The content in the Reference section provides a link to the on-line abstract for each of the articles.


• Bernstein CN, Blanchard JF, Metge C, Yogendran M. Does the use of 5-Aminosalicylates in Inflammatory Bowel Disease prevent the development of Colorectal Cancer? The American Journal of Gastroenterology. 2003;98(12):2784-2788.
  
  
• Bernstein CN, Blanchard JF, Metge C, Yogendran M. The association between corticosteroid use and development of fractures among IBD patients in a population-based database. The American Journal of Gastroenterology . 2003;98(8):1797-1801.
  
  
• Bernstein CN, Wajda A, Blanchard JF. The clustering of other chronic inflammatory diseases in Inflammatory Bowel Disease: A population-based study. Gastroenterology . 2005;12:827-836.
  
  
• Bernstein CN, Banerjee A, Targownik LE, Singh H, Ghia JE, Burchill C, Chateau D, Roos LL. Cesarean section delivery is not a risk factor for development of inflammatory bowel disease: A population-based analysis. Clinical Gastroenterology and Hepatology 2016;14(1):50-57.
  
  
• Bernstein CN, Hitchon CA, Walld R, Bolton JM, Sareen J, Walker JR, Graff LA, Patten SB, Singer A, Lix LM, El-Gabalawy R, Katz A, Fisk JD, Marrie RA, CIHR Team in Defining the Burden and Managing the Effects of Psychiatric Comorbidity in Chronic Immunoinflammatory Disease. Increased burden of psychiatric disorders in inflammatory bowel disease. Inflamm Bowel Dis 2019;25(2):360-368.
  
  
• Bernstein CN, Burchill C, Targownik LE, Singh H, Roos LL. Events within the first year of life, but not the neonatal period, affect risk for later development of inflammatory bowel diseases. Gastroenterology 2019;156(8):2190-2197.

Other research focusing on IBD:


• Marrie RA, Walld R, Bolton JM, Sareen J, Walker R, Patten SB, Singer A, Lix LM, Hitchon CA, El-Gabalawy R, Katz A, Fisk JD, Bernstein CN. Rising incidence of psychiatric disorders before diagnosis of immune-mediated inflammatory disease. Epidemiology and Psychiatric Sciences 2017;Epub ahead of print.
  
  
• Kristensen MS, Kjærulff TM, Ersbøll AK, Green A, Hallas J, Thygesen LC. The Influence of Antidepressants on the Disease Course Among Patients With Crohn’s Disease and Ulcerative Colitis—A Danish Nationwide Register–Based Cohort Study. Inflammatory Bowel Diseases 2019;25(5):886-893.
  
  NOTE: This last article provides the ICD-8 codes for CD and UC, but they have not been validated with Manitoba data.

Cautions and Limitations

• Because IBD is a disease with relapse and remission of symptoms, prevalent cases of CD or UC may be misclassified as incident cases (Bernstein et al., 1999). A long medical history must be obtained from administrative data to determine whether an individual is truly a new case of IBD or if the individual has been diagnosed in the past, experienced remission for a long duration and is currently experiencing a relapse of symptoms (may be evidenced by a long break between IBD-related hospital episodes or physician visits). Bernstein et al. (1999) cautions that prevalence and incidence of IBD may be under- and over-estimated, respectively.
  
  
• Individuals with IBD often experience symptoms long before diagnosis (Burgmann et al., 2006). The onset of IBD may be estimated inaccurately based on administrative data because (1) the condition may be misdiagnosed as Irritable Bowel Syndrome (IBS) or (2) an individual's symptoms may be mild and therefore, further investigation does not occur (Burgmann et al., 2006).
  
  
• Bernstein's validated algorithm, as replicated by Fransoo et al. (2005), is the preferred method to use when calculating the prevalence of IBD. The algorithm used by Raymond et al. (2010) required only one health care contact to define cases of IBD, however it must be noted that in some cases, using one hospitalization or physician visit to identify the prevalence of a disease is not recommended.