Observational Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 14, 2022; 28(30): 4174-4181
Published online Aug 14, 2022. doi: 10.3748/wjg.v28.i30.4174
Epidemiology of inflammatory bowel diseases in the state of Rio Grande do Sul, Brazil
Ornella Sari Cassol, Gilmara Pandolfo Zabot, Rogerio Saad-Hossne, Alexandre Padoin
Ornella Sari Cassol, Department of Coloproctology, IMED Medical School, Passo Fundo 99010260, RS, Brazil
Ornella Sari Cassol, Alexandre Padoin, Graduate Program in Medicine and Health Sciences, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre 90610001, RS, Brazil
Gilmara Pandolfo Zabot, Department of Coloproctology, Coloprocto Canoas Clinic, Canoas 92310205, RS, Brazil
Gilmara Pandolfo Zabot, Department of Coloproctology, Hospital Moinhos de Vento (HMV), Porto Alegre 90035000, RS, Brazil
Rogerio Saad-Hossne, Department of Surgery and Orthopaedics, Universidade Estadual Paulista (UNESP), Botucatu 18618687, SP, Brazil
Author contributions: Cassol OS contributed to data collection, investigation, writing-original draft, and statistical analysis; Zabot GP, Saad-Hossne R, and Padoin A contributed to writing-review and editing.
Supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brasil (CAPES)-Finance Code 001.
Institutional review board statement: This study was performed after approval by the Research Ethics Committee of Pontifícia Universidade Católica do Rio Grande do Sul, Certificate of Presentation for Ethical Appreciation No. 25551019 9 0000 5336; and the ESP/SES/RS Research Ethics Committee, Certificate of Presentation for Ethical Appreciation 25551019 9 3001 5312; this work respected the guidelines of Resolution No. 466/12 of the National Health Council and Law No. 13709 of the General Personal Data Protection Law.
Informed consent statement: This study did not involve the collection of biological material from participants. Data obtained with the data collection instrument were codified, aiming to preserve the participants’ privacy and anonymity. A data use agreement form was signed.
Conflict-of-interest statement: There are no conflicts of interest to report.
Data sharing statement: No additional data are available.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Ornella Sari Cassol, MSc, Professor, Coloproctology, IMED Medical School, 295 Rua Tiradentes, Passo Fundo 99010260, RS, Brazil. cassol.ornella@gmail.com
Received: January 19, 2022
Peer-review started: January 19, 2022
First decision: April 10, 2022
Revised: April 22, 2022
Accepted: July 16, 2022
Article in press: July 16, 2022
Published online: August 14, 2022

This is the first study on the epidemiology of inflammatory bowel diseases (IBDs) in Rio Grande do Sul (RS), the southernmost state of Brazil with the country’s fifth largest population. Crohn’s disease (CD) and ulcerative colitis (UC) are collectively termed IBDs. They have high incidence and prevalence rates in high-income countries, although in recent years there has been a change in the classic geographical distribution of IBDs, with growing rates in traditionally low-incidence regions.


To estimate the incidence and prevalence of IBDs in the RS state, Brazil, between 2014 and 2019.


This is a cross-sectional descriptive observational study. Patients with IBD who had initiated treatment and met the inclusion criteria of the RS state free drug distribution program were included. Data were obtained from registration or renewal records of the RS state specialty pharmacy. The male, female, and total populations were estimated according to mid-year data from the Brazilian Institute of Geography and Statistics, which served as a reference for calculating the incidence and prevalence rates of IBDs during the study period. Results were described using mean, standard deviation, and range.


We included 1082 patients with IBD, of whom 57.5% were female and 42.5% were male. Patients with CD accounted for 72.45% of the sample, and those with UC accounted for 27.54%. IBD prevalence during the study period was 9.51 per 100000 population, of which 6.89 corresponded to people with CD and 2.62, to people with UC. Incidence rates per 100000 population/year were 2.54 in 2014, 2.61 in 2015, 1.91 in 2016, 0.80 in 2017, 0.83 in 2018, and 0.96 in 2019. The mean IBD incidence rate per 100000 population was 1.61, of which 1.17 corresponded to CD and 0.44, to UC. The mean age was 41 years, and patients were mostly aged 30-40 years. Prevalence by region was higher in the state capital metropolitan area: 12.69 per 100000 population.


Our results demonstrated an IBD prevalence of 9.51% and incidence of 1.61 per 100000 population. The patients were predominantly female, and CD was more prevalent than UC.

Keywords: Inflammatory bowel diseases, Crohn’s disease, Ulcerative colitis, Epidemiology, Incidence, Prevalence

Core Tip: This is the first study in the state of Rio Grande do Sul to address the epidemiology of inflammatory bowel diseases (IBDs). We assessed the incidence and prevalence of IBDs between 2014 and 2019, including 1082 patients (57.5% female and 42.5% male). Crohn’s disease corresponded to 72.45% of the analyzed cases and ulcerative colitis, to 27.54%. Prevalence was 9.51% and the mean incidence rate was 1.61 per 100000 population. The mean age was 41 years, and the capital metropolitan area had the highest prevalence. This study showed a similar prevalence to other studies and a decrease in annual incidence rates.