Incidence of IBS and chronic fatigue following GI infection: a population-level study (in Germany)

[Dolphin]

http://gut.bmj.com/content/early/2017/07/25/gutjnl-2017-313713.long

Gut. 2017 Jun 10. pii: gutjnl-2017-313713. doi: 10.1136/gutjnl-2017-313713. [Epub ahead of print]

Incidence of irritable bowel syndrome and chronic fatigue following GI infection: a population-level study using routinely collected claims data.

E1, Schneider A2, Mehring M2, Enck P3.

Author information

Abstract

OBJECTIVES:
To investigate the occurrence of postinfectious IBS in routine outpatient care, comparing different types of GI infection and its interaction with psychosomatic comorbidity.

DESIGN:

Retrospective cohort study using routinely collected claims data covering statutorily insured patients in Bavaria, Germany.

Cases were defined as patients without prior record of functional intestinal disorder with a first-time diagnosis of GI infection between January 2005 and December 2013 and classed according to the type of infection.

Each case was matched by age, sex and district of residence to a patient without history of GI infection.

Prior psychological disorder (depression, anxiety or stress reaction disorder) was assessed in the 2 years prior to inclusion.

Proportional hazards regression models were used to estimate the HRs for GI infection and psychological disorder. Chronic fatigue syndrome (CFS) was assessed as a comparator outcome.

RESULTS:

A total of 508 278 patients with first diagnosis of GI infection were identified, resulting in a matched cohort of 1 016 556 patients.

All infection types were associated with an increased risk of IBS (HR: 2.19-4.25) and CFS (HR 1.35-1.82).

Prior psychological disorder was a distinct risk factor for IBS (HR: 1.73) and CFS (HR: 2.08). Female sex was a further risk factor for both conditions.

CONCLUSION:

Psychological disorder and GI infections are distinct risk factors for IBS.

The high incidence of non-specific GI infectionsuggests that postinfectious IBS is a common clinical occurrence in primary care.

Chronic fatigue is a further significant sequela of GI infection.

KEYWORDS:
biopsychosocial model; chronic fatigue syndrome; irritable bowel syndrome; postinfectious syndrome

PMID:

28601847

DOI:

10.1136/gutjnl-2017-313713

 

[Dolphin]

CFS: defined as a secured diagnosis with G93.3 or F48.0 in one or more quarters during follow-up.

Judging by the data in figure 2, over 5% had a CFS diagnosis in the lowest of the four categories in the follow-up period which lasted an average of 3.75 years. This makes me think that the diagnosis was not that strict.

 

[Dolphin]

From the introduction:

While the biopsychosocial approach to treatment is now widely accepted,3 it remains unclear what role psychological factors play in the pathogenesis of IBS.15 Patients with IBS exhibit more psychological distress and disorder than people with IBS who do not seek medical assistance, leading to the hypothesis that psychosocial factors cause illness behaviour but not IBS itself.16– 18 The interdependence of psychosocial factors and physiological processes poses a central difficulty, yielding a system that is not amenable to causal analysis. Often, the information available to the researcher is dependent to some extent on the factors under investigation. For example, follow-up of patients after an infectious outbreak or case of traveller's diarrhoea is usually subject to recall bias, where patients with psychological disorder are more likely to report having persistent IBS symptoms.19 Furthermore, in the context of the wider primary care setting, the inter-relation of infection models and biopsychosocial approaches have not to date been investigated. Our aim was therefore to use routinely collected ambulatory care data to evaluate the risk of IBS onset in relation to GI infection and psychosomatic comorbidity.

 

[Dolphin]

Cohort

Figure 1 illustrates the selection of the cohort, comprising patients aged between 18 and 60 years with first recorded diagnosis of a gastroenterological infection (ICD-10 codes A01–A09) between January 2005 and December 2013 inclusive. Patients with a prior diagnosis of IBS or functional intestinal disorder were excluded. Infections were classified as Salmonella, Campylobacter, Escherichia coli, other bacterial infection, protozoan infection, viral infection or non-specific infection. Patients with a record of cholera were excluded because this condition is very rare in Bavaria and there are known data quality problems (A00 was used as a default value). Due to the high number of non-specific cases, a random sample of 5% of these patients was taken from each quarterly period and the remaining patients excluded.

 

[Dolphin]

As CFS was not an exclusion criterion, some patients, particularly those with pre-existing psychological comorbidity, had pre-existing CFS.

I think the main figures in the study relate to incident CFS i.e. new cases.

 

[Dolphin]

Proportional hazards model The results of the proportional hazards regression models are presented in table 2 and visualised in figure 3. For the outcome IBS, clear significant HRs are seen for all types of infection, with the HR varying between 2.19 (viral infections) and 4.25 (E. coli). The HR associated with psychological disorder is 1.73, slightly smaller than that for female sex (HR: 2.08). Interaction effects are negatively significant for Campylobacter, other bacterial infections, viral infections and non-specific infections. The interpretation is that GI infection increases risk to a lesser degree among patients who are already at higher risk due to psychological disorder. Patients over the age of 30 years had lower risk of IBS than the reference group of patients aged 18–30 years, with significant HR for the older age groups ranging from 0.89 to 0.92. The time effect was 1.00, indicating that the risk of a documented IBS diagnosis did not change within the period of study.

[..]

All types of GI infection were associated with an increased risk of being diagnosed with CFS. The HRs vary between 1.35 (Campylobacter) and 1.82 (non-specific infection) and are thus substantially lower than the corresponding ratios for IBS. The effects of psychological disorder (HR: 2.08) and female sex (HR: 1.72) were slightly higher than for IBS. The effect of age was reversed, with patients under 30 years experiencing lower risk, although this effect is relatively small. The HR for time is significant but small at 1.01.

Also like with IBS, six out of the seven categories had interaction effects between an infection and psychological disorder less than one. Two of these were statistically significant.

So similarly one could say "The interpretation is that GI infection increases risk to a lesser degree among patients who are already at higher risk due to psychological disorder." I had misread this when reading the abstract and thought that if you had a prior psychological disorder if you got an infection this increased your risk

 

[Dolphin]

One thing I am was concerned about in these studies is that there were likely cases of CFS that were undiagnosed for a number of years.

I know that occurred in my case. And perhaps my doctor might have classified me as a psychological case during that period because I once started crying in the surgery (I think that was the only time I cried that year so I don't accept that I was depressed, I was just upset at that moment because I wasn't getting any answers for my problems). If that was the case then prior psychological disorder wouldn't be a true risk factor as the psychological disorder wasn't occurring before the illness but actually during the illness just it [CFS] hadn't been diagnosed at that stage.

 

[Dolphin]

This shows how it can be difficult to interpret studies at this stage of conditions without more objective tests (that are routinely used):

Approximately two-thirds of all patients with IBS are female and we find that female gender is a stronger predictor of postinfectious IBS than psychological disorder. With the ‘weakened’ IBS definition, however, a higher risk was seen for male patients. A possible explanation is the frequent occurrence of recurrent gastroenteritis, which would reduce the specificity of the weakened IBS definition. On the other hand, both age and gender are known to affect the perception of IBS by patients and physicians.34 35 It is therefore conceivable that some patients presenting with IBS symptoms (eg, in order to receive a sick note) receive a diagnosis of gastroenteritis without further investigation. Conversely, it is possible that female patients and patients with psychological disorder more often receive a diagnosis of IBS. The differences between these outcomes therefore suggest a tentative hypothesis but the data are insufficient to allow any strong conclusion. Further studies are required to investigate how patients with IBS experience primary care and how this depends on age, gender and other factors.

 

[Dolphin]

Various hypotheses have been proposed to explain the role of GI infection and psychological disorder in the pathogenesis of the conditions. One hypothesis relates to the gut-brain axis, where neural, neuroimmune and neuroendocrine pathways facilitate a bidirectional interaction.41 Neurological processes can lead to long-term dysfunction in the gut and digestive system, providing a mechanism through which psychological disorder could lead to IBS. In the reverse direction, the gut microbiota is widely accepted to have a role in brain function and is therefore hypothesised to be a partial determinant of psychological comorbidity in patients with IBS.42 Reduced microbiome diversity and altered composition of the gut bacteria have been observed for patients with IBS and CFS, with connections made to gut inflammation, dysfunction of the mucosal barrier and increased immune activation.43–45 In a wider context, infection and the gut microbiota are the focus of current research into the pathogenesis of autoimmune diseases such as type 1 diabetes and coeliac disease46–48 and of allergic conditions such as asthma.49 50 As such, there are plausible hypotheses that may explain why GI infection leads to an increased risk of both IBS and CFS.

 

[Yabisa]

Take a look of this.
It's not related to CFS /ME but shows how microbioma can affect to the brain metabolism and psycology.
It's been published right on 1st of Sepyember 2017

RESEARCH ARTICLE
Gut microbiome in ADHD and its relation to neural reward anticipation

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0183509