In a recent study published in the journal Neurogastroenterology, researchers examine the prevalence of post-infectious irritable bowel syndrome (PI-IBS) and post-infectious function dyspepsia (PI-FD) following acute gastroenteritis.

Study: Prevalence of irritable bowel syndrome and functional dyspepsia after acute gastroenteritis: systematic review and meta-analysis. Image Credit: zentraddyi3ell / Shutterstock.com

Introduction

Acute infectious gastroenteritis disrupts the gut-brain axis, increasing the risk of developing IBS and FD. These functional gastrointestinal diseases, now referred to as disorders of gut-brain interaction (DGBI), are the most common conditions affecting the gastrointestinal tract.

DGBI can arise following norovirus, rotavirus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, as well as infections with certain bacteria like Campylobacter, Salmonella, Escherichia coli, and the protozoan Giardia. Despite the high prevalence of both IBS and FD, which affect 11% and 7% of the global population, respectively, the etiology and pathophysiology of these conditions remain unclear.

About the study

The current study examines the prevalence of post-infectious IBS (PI-IBS) and post-infectious FD (PI-FD) and stratifies these conditions by the type of organism isolated.

To this end, the researchers performed a systematic review and meta-analysis of 47 studies involving at least 50 adults. All study participants had a history of acute gastroenteritis followed by IBS or FD, with three or more months of follow-up.

Most studies were conducted in Western countries. A random effects model determined the prevalence and likelihood of developing PI-IBS and PI-FD.

Post-infection prevalence

About 15% of study participants had PI-IBS compared to 13% for PI-FD. The North American continent had the highest prevalence of PI-IBS and PI-IFD at 19% and 26%, respectively. Pooled case-control study data showed that after acute gastroenteritis, the risk of developing IBS and FD was four- and three-fold higher, respectively.

When categorized by infection type, PI-IBS was five times more likely to develop after acute bacterial gastroenteritis compared to controls and six times more likely to arise after viral or parasitic infections. The repeated association of these disorders with infectious diseases supports the gradual transition to considering DGBI as organic disorders rather than functional disorders.

According to subtype

The most frequently reported IBS subtype was IBS with diarrhea (IBS-D), which was identified in 46% of cases. With PI-FD, the most frequently reported subtype was that of postprandial distress in 56% of those affected, whereas epigastric pain syndrome affected 25% of cases.

Chronicity

IBS persisted in 50% of cases one to four years later. After five years, IBS was still present in 40% of affected individuals, thus revealing the chronicity of PI-IBS.

By type of infectious agent

Parasitic infection may activate the immune system and disrupt the gut microbiota. IBS developed in 30% of people with intestinal parasitosis, which was attributed to a five-fold increased risk of developing IBS after this type of infection. To date, only two studies have reported this data, thus necessitating further research in this area.

Following bacterial gastroenteritis, 18% of affected individuals developed PI-IBS, attributed to a five-fold increased risk of PI-IBS after this type of infection. Only 11% of affected individuals developed IBS post-viral gastroenteritis; however, the risk of IBS following this type of infection was six-fold higher than controls and primarily attributed to SARS-CoV-2 infection.

By pathogen

When stratified by pathogen, 21% of individuals with Gram-negative Campylobacter infections developed PI-IBS. The highest risk of IBS was observed with Proteobacter, a pro-inflammatory microbial taxon, at 17%.

The risk of PI-IBS in these individuals was five-fold higher than controls, as compared to a four-fold increased risk for infection with the Proteobacter subcategory Enterobacteriacea, which had a 16% prevalence of PI-IBS 16%.

The prevalence of IBS was 10% with SARS-CoV-2, which increased the risk of PI-IBS by five-fold as compared to controls.

Approximately 14% and 10% of individuals developed PI-FD following bacterial and SARS-CoV-2 infections, respectively, whereas PI-FD affected 19% of individuals who were previously infected with Enterobacteriaceae. However, case-control studies failed to show these associations, thus emphasizing the importance of larger samples.

Risk factors

Risk factors for PI-IBS included female sex and prior hospitalization, who were at a 60% and 65% increased risk of this condition, respectively. Furthermore, a history of anxiety and diarrhea for over three weeks increased the risk of PI-IBS by 3.6- and 2.6-fold, respectively.

Conclusions

The current systematic review demonstrated that acute gastroenteritis was followed by a higher prevalence of both PI-IBS and PI-FD over time by 15% and 13%, respectively, despite a relatively stable prevalence over the first post-gastroenteritis year. The likelihood of developing these conditions after experiencing gastroenteritis rose four- and three-fold for IBS and FD, respectively. Moreover, PI-IBS becomes chronic in 40% of cases when present over more than five years, which is a novel finding first reported in the current study.

Taken together, the study findings corroborate those of earlier studies while reporting a slightly higher prevalence of both PI-IBS and PI-FD. The present study included many more recent studies, used newer diagnostic criteria, incorporated more extensive studies, and excluded individuals with existing IBS.

Generally, as acute gastroenteritis is a common disorder worldwide, our findings may be relevant for public health, and physicians should pay heed if their patients present with a recent episode of infectious gastroenteritis.”