Original Contribution
The American Journal of Gastroenterology (2005) 100, 896–904; doi:10.1111/j.1572-0241.2005.41211.x
Characterization of the Alternating Bowel Habit Subtype in Patients with Irritable Bowel Syndrome
Kirsten Tillisch MD1, Jennifer S Labus PhD1, Bruce D Naliboff PhD1, Roger Bolus PhD1, Michael Shetzline MD1, Emeran A Mayer MD1 and Lin Chang MD1
1CNS/WH: Center for Neurovisceral Sciences & Women's Health, Departments of Medicine, Physiology, Psychiatry & Biobehavioral Sciences, UCLA, and the VA Greater Los Angeles Healthcare System, Los Angeles, California; and Novartis Pharmaceuticals, East Hanover, New Jersey
Correspondence: Kirsten Tillisch, MD, CNS/WH: Center for Neurovisceral Sciences & Women's Health, CURE Building 115, Room 223, 11301 Wilshire Boulevard, Los Angeles, CA 90073
Received 20 July 2004; Revised 0000; Accepted 13 December 2004.
Abstract
BACKGROUND:
Due to a wide range of symptom patterns, patients with irritable bowel syndrome (IBS) are often subgrouped by bowel habit. However, the IBS subgroup with alternating bowel habits (IBS-A) has been poorly characterized.
OBJECTIVES:
(i) To determine a set of bowel habit symptom criteria, which most specifically identifies IBS patients with an alternating bowel habit, (ii) to describe IBS-A bowel symptom patterns, and (iii) to compare clinical characteristics among IBS-A, constipation-predominant (IBS-C), and diarrhea-predominant IBS (IBS-D).
METHODS:
One thousand one hundred and two Rome I positive IBS patients were analyzed. Three sets of potential criteria for IBS-A were developed and compared by multirater Kappa test. Gastrointestinal, psychological, extraintestinal symptoms, and health-related quality of life were compared in IBS-A, IBS-C, and IBS-D using 
2 test and analysis of variance (ANOVA).
RESULTS:
Stool consistency was determined to be the most specific criteria for alternating bowel habits. IBS-A patients reported rapid fluctuations in bowel habits with short symptom flares and remissions. There was a greater prevalence of psychological and extraintestinal symptoms in the IBS-A subgroup compared to IBS-C and IBS-D. No differences were seen between bowel habit subtypes in health-related quality of life.
CONCLUSIONS:
IBS-A patients have rapidly fluctuating symptoms and increased psychological comorbidity, which should be taken into account for clinical practice and clinical trials.
