title: Balance of Autonomic Nervous System Predicts Who Benefits from a Self-management Intervention Program for Irritable Bowel Syndrome.
abstract: OBJECTIVE
  To determine if potential biomarkers can be used to identify subgroups of people with irritable bowel syndrome (IBS) who will benefit the most or the least from a comprehensive self-management (CSM) intervention.
  
  
  METHODS
  In a two-armed randomized controlled trial a CSM (n = 46) was compared to a usual care (n = 46) group with follow-up at 3 and 6 months post randomization. Biomarkers obtained at baseline included heart rate variability, salivary cortisol, interleukin-10 produced by unstimulated peripheral blood mononuclear cells, and lactulose/mannitol ratio. Linear mixed models were used to test whether these biomarkers predicted improvements in the primary outcomes including daily abdominal pain, Gastrointestinal Symptom score and IBS-specific quality of life.
  
  
  RESULTS
  The nurse-delivered 8-session CSM intervention is more effective than usual care in reducing abdominal pain, reducing Gastrointestinal Symptom score, and enhancing quality of life. Participants with lower nighttime high frequency heart rate variability (vagal modulation) and increased low frequency/high frequency ratio (sympathovagal balance) had less benefit from CSM on abdominal pain. Salivary cortisol, IL-10, and lactulose/mannitol ratio were not statistically significant in predicting CSM benefit. Baseline symptom severity interacts with treatment, namely the benefit of CSM is greater in those with higher baseline symptoms.
  
  
  CONCLUSIONS
  Cognitively-focused therapies may be less effective in reducing abdominal pain in IBS patients with higher sympathetic tone. Whether this a centrally-mediated patient characteristic or related to heightened arousal remains to be determined.
authors.affiliation: Department of Biobehavioral Nursing and Health Systems, University of Washington, Seattle, WA, USA.
authors.forename: Monica E
authors.initials: ME
authors.lastname: Jarrett
authors.affiliation: Deptartment of Biostatistics and Office for Nursing Research, University of Washington, Seattle, WA, USA.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Cain
authors.affiliation: Department of Biobehavioral Nursing and Health Systems, University of Washington, Seattle, WA, USA.
authors.forename: Pamela G
authors.initials: PG
authors.lastname: Barney
authors.affiliation: Department of Biobehavioral Nursing and Health Systems, University of Washington, Seattle, WA, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Burr
authors.affiliation: Center for Neurovisceral Sciences & Women's Health, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Naliboff
authors.affiliation: Baylor College of Medicine, Houston, TX, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Shulman
authors.affiliation: Department of Medicine, University of Washington, Seattle, WA, USA.
authors.forename: Jasmine
authors.initials: J
authors.lastname: Zia
authors.affiliation: Department of Biobehavioral Nursing and Health Systems, University of Washington, Seattle, WA, USA.
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Heitkemper
keywords: Autonomic nervous system; Interleukin 10; Irritable bowel syndrome; Permeability