Systematic Reviews
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 21, 2019; 25(47): 6866-6875
Published online Dec 21, 2019. doi: 10.3748/wjg.v25.i47.6866
Epidemiology of inflammatory bowel disease in South America: A systematic review
Sriharan Selvaratnam, Santiago Gullino, Lisa Shim, Eric Lee, Alice Lee, Sudarshan Paramsothy, Rupert W Leong
Sriharan Selvaratnam, Santiago Gullino, Lisa Shim, Eric Lee, Alice Lee, Sudarshan Paramsothy, Rupert W Leong, Department of Gastroenterology and Hepatology, Macquarie University Hospital, Sydney 2109, New South Wales, Australia
Author contributions: Selvaratnam S, Gullino S and Leong RW contributed to the conception and design of the study; Selvaratnam S conducted the systematic review, data extraction and manuscript production; Gullino S assisted with independent review of search results; Shim L, Lee E, Lee A, Paramsothy S and Leong RW provided expert opinion and approved the final manuscript.
Conflict-of-interest statement: The authors declare no conflicting interests related to this article.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist and this manuscript was prepared and revised according to these guidelines.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Rupert W Leong, AGAF, FRACP, MBBS, MD, Professor, Department of Gastroenterology and Hepatology, Macquarie University Hospital, 3 Technology Place, Sydney 2109, New South Wales, Australia.
Received: October 18, 2019
Peer-review started: October 18, 2019
First decision: November 22, 2019
Revised: December 2, 2019
Accepted: December 13, 2019
Article in press: December 13, 2019
Published online: December 21, 2019
Research Background

Inflammatory bowel disease (IBD) refers to a chronic inflammatory disorder of the gastrointestinal tract which is thought to arise from an inappropriate inflammatory response to intestinal microbes in a genetically susceptible host. The most common forms of IBD include ulcerative colitis (UC) and Crohn’s disease (CD). Whilst previously regarded predominantly as a disease of western nations, the worldwide epidemiology of IBD rapidly changed at the turn of the twenty-first century with studies demonstrating a plateauing of IBD incidence in western nations whilst IBD incidence and prevalence dramatically rose in developing countries from Asia, Africa and Eastern Europe.

Research motivation

Recent efforts have been made to describe IBD in some developing nations within the South American continent however limited collective data is available from this region. Further collective information about IBD within the South American continent will help provide a valuable insight into the emerging epidemic of this disease with the aim of improving the delivery of high-quality patient-centred care within this region.

Research objectives

To summarise the current literature on Inflammatory Bowel Disease in South America and report the incidence, prevalence and disease characteristics of CD and UC within this continent.

Research methods

A systematic review using PRISMA guidelines was undertaken by searching published studies in major international and regional databases between January 1990 and December 2018. Outcomes considered were incidence, prevalence, phenotype, environmental and genetic factors, ethnicity and gender. A pair of independent reviewers screened and reviewed all identified articles.

Research results

One hundred and sixty two citations were initially retrieved with 18 studies included in this systematic review. The majority of included studies were from Brazil (n = 13, 72%). The incidence of UC ranged from 4.3-5.3/100000 person-years whilst the incidence of CD ranged from 0.74-3.5/100000 person-years. Prevalence ranged from 15.0-24.1/100000 inhabitants for UC and from 2.4-14.1/100000 inhabitants for CD. The incidence and prevalence of both UC and CD has increased significantly over the past 20 years. Pancolitis was the most common disease distribution in patients with UC whilst colonic involvement was the most common distribution in CD. People residing in urban areas were at higher risk of developing both CD and UC.

Research conclusions

IBD is an expanding problem within the South American continent with disease burden increasing at a greater rate than other developing regions. Despite this, there remains a paucity of high-queality epidemiological studies from this region. With a total popuation exceeding 400 million, the South American continent is expected to carry a significant proportion of the future global IBD burden.

Research perspectives

This represents the first systematic review to examine the epidemiology of Inflammatory Bowel Disease within South America. Given the current scarcity of high-quality IBD epidemiological studies from this region, a concerted and collaborative South American approach is vital. The establishment of central registries within individual countries would be a reasonable first step to overcome the considerable gap of evidence in this region by facilitating the collection of robust, representative and longitudinal data which may help identify aetiological factors, environmental triggers and modifiable risk factors within this unique population. Further education of the primary care sector, particularly in identifying risk factors which can be easily and cheaply modified (such as cigarette smoking and breast feeding) as well as differentiating IBD from enteric infection and Irritable Bowel Syndrome, will also help decrease morbidity, minimise misdiagnosis and improve patient care. This in turn will help facilitate the delivery of high-quality, patient-centred care for South American patients with IBD.