title: Gastrointestinal and psychological mediators of health-related quality of life in IBS and IBD: a structural equation modeling analysis.
abstract: OBJECTIVE
  Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) are chronic gastrointestinal (GI) syndromes in which both GI and psychological symptoms have been shown to negatively impact health-related quality of life (HRQOL). The objective of this study was to use structural equation modeling (SEM) to characterize the interrelationships among HRQOL, GI, and psychological symptoms to improve our understanding of the illness processes in both conditions.
  
  
  METHODS
  Study participants included 564 Rome positive IBS patients and 126 IBD patients diagnosed via endoscopic and/or tissue confirmation. All patients completed questionnaires to assess bowel symptoms, psychological symptoms (SCL-90R), and HRQOL (SF-36). SEM with its two components of confirmatory analyses and structural modeling were applied to determine the relationships between GI and psychological symptoms and HRQOL within the IBS and IBD groups.
  
  
  RESULTS
  For both IBD and IBS, psychological distress was found to have a stronger direct effect on HRQOL (-0.51 and -0.48 for IBS and IBD, respectively) than GI symptoms (-0.25 and -0.28). The impact of GI symptoms on psychological distress was stronger in IBD compared with IBS (0.43 vs. 0.22; P<0.05). The indirect effect of GI symptoms on HRQOL operating through psychological distress was significantly higher in IBD than IBS (-0.21 vs. -0.11; P<0.05).
  
  
  CONCLUSIONS
  Psychological distress is less dependent on GI symptom severity in IBS compared with IBD even though the degree that psychological distress impacts HRQOL is similar. The findings emphasize the importance of addressing psychological symptoms in both syndromes.
authors.affiliation: Center for Neurobiology of Stress, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-7378 , USA.
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Naliboff
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Kim
authors.forename: Roger
authors.initials: R
authors.lastname: Bolus
authors.forename: Charles N
authors.initials: CN
authors.lastname: Bernstein
authors.forename: Emeran A
authors.initials: EA
authors.lastname: Mayer
authors.forename: Lin
authors.initials: L
authors.lastname: Chang
mesh_terms: D000328:Adult; D016009:Chi-Square Distribution; D016099:Endoscopy, Gastrointestinal; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000503:physiopathology / Q000523:psychology*; D043183:Irritable Bowel Syndrome / Q000503:physiopathology* / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011788:Quality of Life; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
references.citation: J Pediatr. 2004 Apr;144(4):449-54
references.pmid: 15069391
references.citation: J Behav Med. 2003 Feb;26(1):1-18
references.pmid: 12690943
references.citation: Digestion. 2005;72(2-3):86-96
references.pmid: 16127275
references.citation: Gut. 1998 Jan;42(1):47-53
references.pmid: 9505885
references.citation: Am J Gastroenterol. 2009 May;104(5):1298-313; quiz 1314
references.pmid: 19337242
references.citation: Eur J Gastroenterol Hepatol. 2003 Feb;15(2):165-72
references.pmid: 12560761
references.citation: Inflamm Bowel Dis. 2006 Jan;12(1):38-46
references.pmid: 16374257
references.citation: Am J Gastroenterol. 1999 Oct;94(10):2929-35
references.pmid: 10520847
references.citation: Am J Psychiatry. 1993 Oct;150(10):1502-6
references.pmid: 8379554
references.citation: Am J Gastroenterol. 2008 Oct;103(10):2536-43
references.pmid: 18637089
references.citation: Tunis Med. 2010 Dec;88(12):933-6
references.pmid: 21136364
references.citation: Am J Gastroenterol. 2008 Aug;103(8):1989-97
references.pmid: 18796096
references.citation: Clin Gastroenterol Hepatol. 2009 Jan;7(1):48-53
references.pmid: 18848909
references.citation: Ann Clin Psychiatry. 2001 Mar;13(1):25-30
references.pmid: 11465682
references.citation: Psychosomatics. 1993 May-Jun;34(3):229-34
references.pmid: 8493304
references.citation: Ann Intern Med. 1990 Dec 1;113(11):828-33
references.pmid: 2240898
references.citation: Gastroenterology. 1994 Oct;107(4):1040-9
references.pmid: 7926457
references.citation: Med J Aust. 1979 May 5;1(9):372-4
references.pmid: 470749
references.citation: Gastroenterology. 2006 Apr;130(5):1447-58
references.pmid: 16678558
references.citation: J Psychosom Res. 2008 Feb;64(2):139-48
references.pmid: 18222127
references.citation: Inflamm Bowel Dis. 2006 Jan;12(1):47-52
references.pmid: 16374258
references.citation: J Child Sex Abus. 2005;14(1):27-38
references.pmid: 15914403
references.citation: Gastroenterology. 1989 Oct;97(4):932-7
references.pmid: 2777045
references.citation: Aliment Pharmacol Ther. 2008 Aug 1;28(3):344-52
references.pmid: 19086332
references.citation: Scand J Gastroenterol. 2003 Oct;38(10):1031-8
references.pmid: 14621276
references.citation: Curr Opin Pharmacol. 2008 Dec;8(6):715-23
references.pmid: 18760380
references.citation: Gastroenterology. 2000 Sep;119(3):654-60
references.pmid: 10982758
references.citation: Am J Gastroenterol. 2002 Feb;97(2):389-96
references.pmid: 11866278
references.citation: Inflamm Bowel Dis. 2009 Jul;15(7):1105-18
references.pmid: 19161177
references.citation: Behav Res Ther. 1994 Feb;32(2):217-26
references.pmid: 8155059
references.citation: Gastroenterology. 2002 Apr;122(4):1140-56
references.pmid: 11910364
references.citation: Inflamm Bowel Dis. 2010 Oct;16(10):1685-95
references.pmid: 20155849
references.citation: Can J Gastroenterol. 2008 May;22(5):475-83
references.pmid: 18478133
references.citation: Am J Gastroenterol. 2010 Sep;105(9):1994-2002
references.pmid: 20372115
references.citation: Aliment Pharmacol Ther. 2002 Jun;16(6):1171-85
references.pmid: 12030961
references.citation: Gastroenterol Clin Biol. 2006 Feb;30(2):241-6
references.pmid: 16565657
references.citation: Am J Gastroenterol. 2009 Dec;104(12):2959-69
references.pmid: 19755973
references.citation: Arch Intern Med. 2004 Sep 13;164(16):1773-80
references.pmid: 15364671
references.citation: Gut. 2008 Oct;57(10):1386-92
references.pmid: 18390994
references.citation: Inflamm Bowel Dis. 2005 May;11(5):488-96
references.pmid: 15867589
references.citation: Am J Gastroenterol. 2005 Apr;100(4):896-904
references.pmid: 15784038
references.citation: Am J Gastroenterol. 2004 Aug;99(8):1572-8
references.pmid: 15307879
references.citation: J Gastroenterol Hepatol. 2011 May;26(5):916-23
references.pmid: 21214889
references.citation: Eur J Gastroenterol Hepatol. 2010 Jul;22(7):862-7
references.pmid: 19701092
references.citation: Am J Gastroenterol. 2003 May;98(5):1088-93
references.pmid: 12809832
references.citation: Gastroenterology. 2002 Dec;123(6):2108-31
references.pmid: 12454866