The prevalence of gastroesophageal reflux-type symptoms (GERS) is roughly four times greater in individuals with irritable bowel syndrome (IBS) than in those without IBS, a systematic review and meta-analysis suggests.
The study was published online in the American Journal of Gastroenterology.
IBS and GERS are very common in the general population and the two appear to be related, although the reasons for the overlap "remain speculative," Dr Rebecca Lovell and Dr Alexander Ford, from Leeds Gastroenterology Institute in the United Kingdom, note in their paper. Shared pathophysiological mechanisms are one possibility, they say.
Dr Hashem B El-Serag, chief of gastroenterology and hepatology at Baylor College of Medicine, Houston, Texas, agrees. Furthermore, he said, "These findings highlight the clustering of functional symptoms, and the difficulty in managing these patients by using uni-dimensional therapies such acid suppression for GERD or laxatives for IBS with constipation."
"These medications, while may help the individual symptom, are unlikely to address the shared pathophysiology or for that matter the larger needs of patients with functional disorders," said Dr El-Serag, who was not involved in the study.
How the study was done
In a comprehensive literature review, Dr Lovell and Dr Ford evaluated 390 papers, identified 80 studies that reported the prevalence of IBS in adults, and 13 that reported the proportion of individuals with GERS in the same population, which they included in their meta-analysis.
The 13 studies had a total of 49 939 participants. The cohorts were geographically diverse - four from Northern Europe, four from Southeast Asia, two from North America, and one each from the Middle East, Australasia and Southern Europe.
According to the researchers, the prevalence of GERS in IBS was 42%. The pooled odds ratio (OR) for GERS in individuals with IBS, compared with those without IBS, was 4.17.
Systematic summary of existing studies
The positive association between GERS and IBS persisted for all geographical regions examined, the researchers say, and for all diagnostic criteria used. The degree of overlap between IBS and GERS varied from 14.2% when the Rome II criteria for IBS were used to 26.7% with the Manning criteria.
"This study," Dr El-Serag commented, "is a systematic summary of existing studies performed at the general population level. It is, however, unknown how many of the individuals who self report symptoms are actually bothered by these symptoms enough to seek medical care."
"To the degree that these self-reported symptoms in the general population reflect clinically important disorders, the findings suggest shared risk factors for IBS and GERD symptoms," he continued. "The most readily available explanation is that a good proportion of patients with GERD symptoms have predominantly or completely functional symptoms (i.e., GERD symptoms in the absence of a demonstrably abnormal acid or non acid reflux)."
"If the findings are confirmed in clinical settings, then clinicians should maintain a high index of suspicion for the coexistence of these disorders in the same patient and consider management strategies that target both functional disorders," Dr El-Serag said.
Dr Lovell and Dr Ford say a strength of the study is the inclusion of only community-based studies, which "should reduce the likelihood that the reported prevalence of IBS or GERS were inflated and increase the generalisability of our results to individuals consulting in primary care with such symptoms."
Use of a random effects model to allow for a more conservative estimated of the pooled OR for GERS in IBS is another strength, they say.
Weaknesses of the analysis include the fact that few of the included studies scored higher than four (out of a possible total score of eight) on the quality scale they used, although the scale has not been validated and there is no recommendation as to what threshold should be used to define higher-quality studies, they say.
The authors note, "Although the majority of individuals in the studies identified in this systematic review and meta-analysis had symptoms that could be classified as either IBS alone or GERS alone, our results still demonstrate that there is considerable overlap between the two conditions, and that individuals with IBS are at significantly increased risk of co-existent GERS. Reasons for this cannot be elucidated by a study such as ours."
Going forward, Dr Lovell and Dr Ford say, "Future research should address reasons for this strong association, and we recommend that when physicians encounter patients who report symptoms of IBS, they should, as part of their routine clinical history-taking process, screen for co-existent GERS."
The study did not receive financial support and the authors have disclosed no potentially competing interests. The authors were unavailable to comment by press time.
(Reuters Health, October 2012)
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