Many individuals experience lower gastrointestinal (GI) tract symptoms, most commonly attributable to functional conditions.
These individuals are frequently diagnosed with irritable bowel syndrome (IBS) based on their symptoms.
However, some may require additional testing or referral to specialists before this diagnosis is made.
Dr Alexander Ford and colleagues from Canada systematically reviewed the literature of the accuracy of individual symptoms and combinations of findings in diagnosing irritable bowel syndrome.
The team searched MEDLINE and EMBASE for prospective studies reporting on unselected cohorts of adult patients with lower gastrointestinal tract symptoms recorded before investigation.
|The positive likelihood ratio for looser stools at onset of abdominal pain was 2.1 pain|
|Journal of the American Medical Association|
Studies prospectively evaluating accuracy of individual symptoms or combinations of findings were compared with results from investigations of the lower gastrointestinal tract.
The team reported that 2 authors independently assessed studies and extracted data.
The researchers then estimated likelihood ratios of individual symptoms and combinations of findings in diagnosing irritable bowel syndrome.
The researchers identified 10 studies evaluating 2,355 patients, with a summary prevalence of irritable bowel syndrome following investigation of 57%.
Individual symptom items yielded positive likelihood ratios from 1.2 for passage of mucus per rectum to 2.1 for looser stools at onset of abdominal pain.
The team identified negative likelihood ratios of 0.29 for no lower abdominal pain, and 0.88 for no passage of mucus per rectum in diagnosing irritable bowel syndrome.
The Manning criteria had a summary positive likelihood ratio of 2.9, and a summary negative likelihood ratio of 0.29.
The researchers observed that the Rome I criteria had a positive likelihood ratio of 4.8, and a negative likelihood ratio of 0.34.
The Kruis scoring system provided a summary positive likelihood ratio of 8.6, and a summary negative likelihood ratio of 0.26.
The Rome II and III criteria have not been studied.
Dr Ford’s team cocluded, “Individual symptoms have limited accuracy for diagnosing irritable bowel syndrome in patients referred with lower gastrointestinal tract symptoms.”
“The accuracy of the Manning criteria and Kruis scoring system were only modest.”
“Despite strong advocacy for use of the Rome criteria, only the Rome I classification has been validated.”
“Future research should concentrate on validating existing diagnostic criteria or developing more accurate ways of predicting a diagnosis of irritable bowel syndrome without the need for investigation of the lower gastrointestinal tract.”