TRENDS IN INFLAMMATORY BOWEL DISEASE INCIDENCE AND PREVALENCE ACROSS EPIDEMIOLOGIC STAGES: A GLOBAL SYSTEMATIC REVIEW WITH META-ANALYSIS
Authors: Gorospe Julia , Windsor Joseph , Hracs Lindsay , Coward Stephanie , Buie Michael , Quan Joshua , Caplan Lea , Markovinovic Ante , Cummings Michael , Goddard Quinn , Williamson Tyler , Abbey Yvonne , Abreu Maria , Ali Raja , Abdullah Murdani , Altuwaijri Mansour , Ahuja Vineet , Balderramo Domingo , Banerjee Rupa , Benchimol Eric , Bernstein Charles , Brunet-Mas Eduard , Burisch Johan , Chong Vui Heng , Dotan Iris , Dutta Usha , El Ouali Sara , Forbes Angela , Forss Anders , Gearry Richard , Dao Viet Hang , Hartono Juanda , Hilmi Ida , Julian-Banos Fabian , Kaibullayeva Jamilya , Kelly Paul , Kotze Paulo , Lakatos Peter , Lees Charlie , Limsrivilai Julajak , Loftus Edward , Ludvigsson Jonas , Mak Joyce , Ng Ka Kei , Olen Ola , Panaccione Remo , Paudel Mukesh , Quaresma Abel , Rubin David , Simadibrata Marcellus , Sun Yang , Suzuki Hidekazu , Toro Martin , Turner Dan , Vergara Beatriz Iade , Wei Shu-Chen , Yamamoto-Furusho Jesus , Yang Kuk-Kyun , Ng Siew , Kaplan Gilaad 
Published: January 2024

Abstract

BACKGROUND
Rising incidence and prevalence of inflammatory bowel disease (IBD) observed historically in early-industrialized regions now also appear in newly-industrialized and emerging regions. The epidemiology of IBD has been proposed to progress across epidemiologic stages: 1. Emergence (low incidence and prevalence); 2. Acceleration in Incidence (rapid rising incidence); and 3. Compounding Prevalence (stabilizing incidence, rapid rising prevalence).

AIM
To gather real-world data on the incidence and prevalence of IBD and characterize global regions in each epidemiologic stage by meta-analyses.

METHODS
Two previous systematic reviews (database inception–2010; 2010–2016) were updated with a search of MEDLINE, Embase, PubMed, and Web of Science (2017–2023) to identify all population-based studies reporting the incidence or prevalence of Crohn’s disease (CD) or ulcerative colitis (UC). International partners provided a secondary review of the included studies from their local regions. Incidence and prevalence rates (per 100,000 population), stratified by epidemiologic stage, were meta-analyzed to determine pooled rates with associated 95% confidence intervals (95%CI). A Cochrane Q test was used to investigate differences between epidemiologic stages for both CD and UC.

RESULTS
After assessing 1,250 manuscripts, a total of 491 studies (439 incidence, 228 prevalence) from 80 global regions spanning 1920-2022 were identified by the systematic review (Figure 1). All data identified with our search strategy are available to view in an open-access, online interactive data repository (https://gives21.shinyapps.io/dashboard/) created with Shiny for R. The pooled incidence of CD and UC per 100,000 person-years rose from 0.28 (95%CI: 0.21, 0.36) and 0.57 (95%CI: 0.47, 0.69) in Stage 1 to 2.13 (95%CI: 1.88, 2.42) and 4.05 (95%CI: 3.65, 4.50) in Stage 2 to 9.34 (95%CI: 8.73, 9.99) and 14.07 (95%CI: 13.09, 15.12) in Stage 3 (Table 1). Similarly, the pooled prevalence of CD and UC per 100,000 persons rose from 1.96 (95%CI: 1.41, 2.74) and 6.35 (95%CI: 4.45, 9.07) in Stage 1 to 22.18 (95%CI: 17.96, 27.38) and 45.36 (95%CI: 37.84, 54.38) in Stage 2 to 186.18 (95%CI: 163.18, 212.42) and 255.92 (95%CI: 230.60, 284.02) in Stage 3 (Table 1). Subgroup analysis confirmed differences in both incidence and prevalence for CD and UC between epidemiologic stages (p&lt;0.001).

DISCUSSION
This is the most comprehensive systematic review on the incidence and prevalence of IBD. The amalgamated real-world data from this study highlight the rising global burden of IBD across three distinct epidemiologic stages: 1. Emergence, 2. Acceleration in Incidence, and 3. Compounding Prevalence.

Figure 1 Systematic review study selection flowchart including a brief overview of two previous systematic reviews: Molodecky, N.A. et al. Gastroenterology. 2012;142(1):46-54 and Ng, S.C. et al. Lancet. 2017;390(10114):2769-78.

Table 1 Pooled incidence and prevalence rates per 100,000 population for Crohn’s disease and ulcerative colitis. Cochrane Q subgroup analysis for difference in estimates between epidemiologic stages. † Represents the number of study-subregion groups used in the calculation of pooled rates and their 95% confidence intervals.