Changes in inflammatory bowel disease subtype during follow-up and over time in 44,302 patients

Figures & data

Table 1. Proportion inflammatory bowel disease unclassified (IBD-U) in well-characterized cohorts with at least 400 participants.

Author	Country	Study population	n (%) IBD-U/IC
Children
Sawczenko, 2001	UK & Ireland	Incident cases 1998–1999 age <16, n = 739	12%
Auvin, 2005	France	Incident cases 1988–1999 age <17, n = 509	n=20 (4%)
Turunen, 2006	Finland	Incident cases 1987–2003, age <18, n = 604	n=83 (14%)
Pozler, 2006	Czech Republic	Incident cases 1990–2001, age <15, n = 470	n = 45 (10%)
Van Limbergen, 2008	Scotland	Incident cases 2002 age < 17, n = 416	n=41 (10%)
Hope, 2012	Ireland	Incident cases 2000–2010 age <16, n = 406	n=39 (10%)
Henderson, 2012	Scotland	Incident cases 2003–2008 age <16, n = 436	n=56 (13%)
Adamiak, 2013	USA	Incident cases 2000–2007 age <18, n = 992	5% (based on IR IC: 0.5, IR IBD 9.5)
Martin-de-Carpi, 2013	Spain	Incident cases 1985–1995 age <18, n = 495	n = 19 (4%)
Müller, 2013	Hungary	Incident cases 2007–2009 age <18, n = 420	n = 25 (6%)
Malaty, 2013	USA	Incident cases 1986–2003, n = 420	n = 78 (22%)
Winter, 2015	Europe and Israel	Incident cases 2005–2013 age <18, N = 3461	n = 265 (8%)
Rinawi, 2017	Israel	Incident cases 1986–2013 age <18, n = 723	n = 53 (7%)
Adults
Burisch, 2014	Europe	Incident cases 2010 age ≥15, n = 1515	n = 167 (11%)
Adults and children
Meucci, 1999	Italy	Incident cases 1988–1993, n = 1113	n = 50 (4%)
Vind, 2006	Denmark	Incident cases 2003–2005, n = 562	n = 27 (5%)
Gearry, 2006	New Zeeland	Incident cases 2004–2005, n = 1420	n = 37 (3%)
Henriksen, 2006	Norway	Incident cases 1990–1993, n = 843	n = 40 (5%)
Herrinton, 2008	USA	Prevalent cases 1996–2002, n = 2366	n = 101 (4%)
Romberg-Camps, 2009	Netherlands	Incident cases 1991–2003, n = 1187	n = 81 (7%)
Ng, 2013	Asia-Pacific	Incident cases 2011–2012, n = 419	n = 21 (5%)
Nuij, 2013	Netherlands	Incident cases 2006–2007, n = 413	n = 24 (6%)
Björnsson, 2015	Iceland	Incident cases 1995–2009, n = 1175	n = 12 (1%)
Studd, 2016	Australia	Prevalent cases 2011, n = 1011 Incident cases 2010–2011, n = 71	Prevalent cases n = 25 (2.5%) Incident cases n = 6 (8.4%)
Hammer, 2016	Denmark	Incident cases 1960–2014, n = 664	n = 134 (20%)
Ng, 2016	China	Prevalent cases1981–2014, n = 2575	n = 51 (2%)

IBD: Inflammatory bowel disease; IBD-U: IBD-unclassified; UC: ulcerative colitis; CD: Crohn’s disease; IC: indeterminate colitis.

Table 2. Register-based definition and proportion of inflammatory bowel disease unclassified (IBD-U) in different studies.

Author	Country	Study population	Definition	Proportion IBD-/IC
Benchimol, 2009	Canada	Incident cases 1994–2005 age <18 yrs, n=593	<5/7 diagnoses of UC or CD	4%
Lehtinen, 2011	Finland	Incident cases 1987–2003 n=1880	ICD code + pharmacological reimbursement	2% IC
				30% unknown
Benchimol, 2014	Canada	Prevalent cases 2008 n = 74,817	Pediatric: <5/7 last available diagnoses of UC or CD Adults: UC<5/9 last available diagnoses of UC or CD	4%
Benchimol, 2014	Canada	Pediatric incident cases 1994–2009 n = 7143	<5/7 last available diagnoses of UC or CD	<6 yrs: 11%
				6–9 yrs: 10%
				≥10 yrs: 6.5%
Leddin, 2014	Canada	Incident cases 1996–2009 n=7153	Score of −2 to +2 where physician billing claim was scored as + 1 (UC) or −1 (CD) and hospital discharge was scored + 2 (UC) or −2 (CD)	16%
Bitton, 2014	Canada	Prevalent cases 2001–2008 n=41,176	Score of −2 to +2 where physician billing claim was scored as + 1 (UC) or −1 (CD) and hospital discharge was scored + 2 (UC) or −2 (CD)	3.5%
Büsch, 2014	Sweden	Prevalent cases 2010 n = 61,344	Diagnosis of both UC and CD/any diagnosis of IBD-unclassified	16%
Ludvigsson, 2017	Sweden	Pediatric prevalent cases 2010 n = 1432	Diagnosis of both UC and CD/ any diagnosis of IBD-unclassified	21%
Current study, 2018	Sweden	Incident cases 1964–2014 < 18 yrs n = 9468, ≥18 yrs n = 83,005	Incident: Diagnosis of IBD-U/ both UC and CD during 2 first visits Prevalent: Any diagnosis of IBD-U or mixed diagnoses and no CD-related codes the last 5 years	<18 yrs: 10%
				≥18 yrs: 8%
				<18 yrs: 12%
				≥18 yrs: 8%

IC: indeterminate colitis; ICD: international classification of disease; UC: ulcerative colitis; CD: Crohn’s disease; yrs: years.

Figure 1. Frequency and timing of each type of change in inflammatory bowel disease (IBD) subtype since first IBD diagnosis in patients with incident IBD 2002–2014 who changed diagnosis at some point during follow-up (n = 7930 out of 44,302). A patient can contribute several types of diagnostic changes and the same type of diagnostic change several times.

Figure 2. Number of changes in inflammatory bowel disease (IBD) subtypes in patients with incident IBD 2002–2014, who changed diagnosis at some point during follow-up (n = 7930 out of 44,302).