Approaches to Diagnosing IBS
Background Irritable bowel syndrome (IBS) is a complex, heterogeneous disease which can be challenging to diagnose. No study has identified and assessed the accuracy of all available methods of diagnosing IBS.
Aim To conduct a systematic review of the literature to identify and assess accuracy of symptom-based diagnostic criteria, biomarkers, psychological markers or combinations thereof.
Methods MEDLINE, EMBASE and EMBASE Classic were searched (until April 2015) to identify studies reporting accuracy of available methods to diagnose IBS in adult populations. Eligible studies assessed accuracy of these diagnostic tests against an accepted reference standard. Data were extracted to calculate positive and negative likelihood ratios, with 95% confidence intervals (CIs), of the diagnostic test utilised. Where more than one study used the same test, data were pooled in a meta-analysis.
Results Twenty-two studies (7106 patients) were eligible. Positive and negative likelihood ratios of the current gold standard, the Rome III criteria, were 3.35 (95% CI: 2.97–3.79) and 0.39 (95% CI: 0.34–0.46), similar to other symptom-based criteria. Eleven biomarkers performed no better than symptom-based criteria. Psychological markers performed well in one study. Five different combinations were assessed. The best in terms of positive likelihood ratio was faecal calprotectin, intestinal permeability and Rome I criteria (26.4; 95% CI: 11.4–61.9), and in terms of negative likelihood ratio serum-based biomarkers and psychological markers (0.18; 95% CI: 0.12–0.25).
Conclusions Symptom-based diagnostic criteria, biomarkers and psychological markers performed modestly in predicting IBS. Combining symptoms with markers appears more effective, and may represent the way forward in the diagnosis of IBS.
Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder characterised by abdominal pain associated with a change in stool form and/or frequency. The condition has an estimated prevalence of up to 20% in Western populations, and the impact of IBS socially and economically is significant, with up to 12% of IBS patients having to stop work completely. There is an estimated direct cost per patient to the US economy of between $742 and $7547. The pathogenesis of IBS is poorly understood and, as yet, no unifying structural or physiological cause has been identified. Furthermore, making a positive diagnosis of IBS is challenging as the symptoms often overlap with those of organic GI disease such as colorectal cancer, inflammatory bowel disease, bile acid malabsorption, and coeliac disease.
Symptom-based diagnostic criteria were developed to aid in making a positive diagnosis of IBS and are the current gold standard, the latest iteration of these being the Rome III criteria. However, these criteria have been criticised for being overly complex and impractical in a clinical setting, particularly in primary care where the majority of IBS is diagnosed and managed. Partly as a consequence of this, interest has grown in developing novel biomarkers, measurable biological characteristics including physiological responses, proteins, genes and metabolites, as a diagnostic tool. Patients with IBS are more likely to have higher levels of anxiety, neuroticism or mood instability when compared to healthy individuals and those with other lower GI disorders. As a result, studies have also been conducted to assess whether measures of psychological well-being can aid in the diagnosis of IBS.
We, and others, have previously examined the accuracy of symptom-based diagnostic criteria in predicting IBS. However, since these meta-analyses were performed there have been more studies published, as well as the description of novel attempts to diagnose IBS. As the Rome IV process for functional GI disorders is due to report in 2016, a summary of the accuracy of all available approaches, including symptoms, biomarkers, psychological markers and combinations of the above would seem timely. We have therefore conducted an updated systematic review and meta-analysis examining this issue.
Abstract and Introduction
Abstract
Background Irritable bowel syndrome (IBS) is a complex, heterogeneous disease which can be challenging to diagnose. No study has identified and assessed the accuracy of all available methods of diagnosing IBS.
Aim To conduct a systematic review of the literature to identify and assess accuracy of symptom-based diagnostic criteria, biomarkers, psychological markers or combinations thereof.
Methods MEDLINE, EMBASE and EMBASE Classic were searched (until April 2015) to identify studies reporting accuracy of available methods to diagnose IBS in adult populations. Eligible studies assessed accuracy of these diagnostic tests against an accepted reference standard. Data were extracted to calculate positive and negative likelihood ratios, with 95% confidence intervals (CIs), of the diagnostic test utilised. Where more than one study used the same test, data were pooled in a meta-analysis.
Results Twenty-two studies (7106 patients) were eligible. Positive and negative likelihood ratios of the current gold standard, the Rome III criteria, were 3.35 (95% CI: 2.97–3.79) and 0.39 (95% CI: 0.34–0.46), similar to other symptom-based criteria. Eleven biomarkers performed no better than symptom-based criteria. Psychological markers performed well in one study. Five different combinations were assessed. The best in terms of positive likelihood ratio was faecal calprotectin, intestinal permeability and Rome I criteria (26.4; 95% CI: 11.4–61.9), and in terms of negative likelihood ratio serum-based biomarkers and psychological markers (0.18; 95% CI: 0.12–0.25).
Conclusions Symptom-based diagnostic criteria, biomarkers and psychological markers performed modestly in predicting IBS. Combining symptoms with markers appears more effective, and may represent the way forward in the diagnosis of IBS.
Introduction
Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder characterised by abdominal pain associated with a change in stool form and/or frequency. The condition has an estimated prevalence of up to 20% in Western populations, and the impact of IBS socially and economically is significant, with up to 12% of IBS patients having to stop work completely. There is an estimated direct cost per patient to the US economy of between $742 and $7547. The pathogenesis of IBS is poorly understood and, as yet, no unifying structural or physiological cause has been identified. Furthermore, making a positive diagnosis of IBS is challenging as the symptoms often overlap with those of organic GI disease such as colorectal cancer, inflammatory bowel disease, bile acid malabsorption, and coeliac disease.
Symptom-based diagnostic criteria were developed to aid in making a positive diagnosis of IBS and are the current gold standard, the latest iteration of these being the Rome III criteria. However, these criteria have been criticised for being overly complex and impractical in a clinical setting, particularly in primary care where the majority of IBS is diagnosed and managed. Partly as a consequence of this, interest has grown in developing novel biomarkers, measurable biological characteristics including physiological responses, proteins, genes and metabolites, as a diagnostic tool. Patients with IBS are more likely to have higher levels of anxiety, neuroticism or mood instability when compared to healthy individuals and those with other lower GI disorders. As a result, studies have also been conducted to assess whether measures of psychological well-being can aid in the diagnosis of IBS.
We, and others, have previously examined the accuracy of symptom-based diagnostic criteria in predicting IBS. However, since these meta-analyses were performed there have been more studies published, as well as the description of novel attempts to diagnose IBS. As the Rome IV process for functional GI disorders is due to report in 2016, a summary of the accuracy of all available approaches, including symptoms, biomarkers, psychological markers and combinations of the above would seem timely. We have therefore conducted an updated systematic review and meta-analysis examining this issue.
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