Analyzing the Content of Outcome Measures in Clinical Trials on Irritable Bowel Syndrome Using the International Classification of Functioning, Disability and Health as a Reference

Zusammenfassung

Hintergrund: Patienten mit Reizdarmsyndrom (RDS) berichten über eine erhebliche Beeinträchtigung ihrer funktionalen Gesundheit durch die Darmsymptomatik. Dagegen scheinen im Outcome-Assessment klinischer Studien zum RDS funktionale Aspekte mit Ausnahme der Erhebung gastrointestinaler Symptome unterrepräsentiert zu sein. Ziel: Ziel der Studie war es deshalb, inhaltliche Aspekte des Outcome-Assessments klinischer Studien zum RDS zu analysieren. Methodik: Dazu wurde eine systematische Literaturanalyse in Form einer quantitativen Inhaltsanalyse durchgeführt. Als Kodiersystem wurde die Internationale Klassifikation der Funktionsfähigkeit, Behinderung und Gesundheit (ICF) verwendet. Die Selektion der Outcome-Instrumente erfolgte auf der Basis aller klinischen randomisierten kontrollierten Studien zum RDS, die in PubMed seit Beginn der Registrierung bis April 2002 veröffentlicht wurden. Aus den Outcome-Instrumenten wurden definierte Textstellen, so genannte Kodiereinheiten, ausgewählt, die dann mittels der ICF verschlüsselt wurden. Eine Kodiereinheit musste eine Einzelinformation im Sinne eines funktionalen Gesundheitsaspektes beschreiben. Bei Verwendung von Tests als Outcome-Instrumente wurden die Ziele der Tests semantisch impliziert. Nur 2-stufige ICF-Kategorien, die im Outcome-Assessment von mindestens 10 % der Studien vorkamen, wurden berücksichtigt. Alle Review-Schritte wurden von drei unabhängigen Ratern durchgeführt. Ergebnisse: 99 Studien wurden eingeschlossen. In 88 Studien wurden Einzelitems, in 42 Studien klinische oder paraklinische Tests, in 24 Studien Fragebogen als Outcome-Instrumente verwendet. 90 % der selektierten Kodiereinheiten (n = 2271) konnten der ICF zugewiesen werden. ICF-Kategorien, die gastrointestinale Symptome beschreiben, wurden in Abhängigkeit ihres spezifischen Informationsgehaltes im Outcome-Assessment von 37 bis 85 Studien berücksichtigt, im Vergleich zu extragastrointestinalen Symptomen in 10 bis 22 Studien. Über die ICF-Komponente „Körperfunktionen” hinausgehende Inhalte wurden kaum erhoben. Klare säkulare Trends für einzelne ICF-Kategorien konnten nicht beobachtet werden. Nur ein RDS-spezifischer Fragebogen betrachtete über die gastrointestinale Symptomatik hinausgehende Gesundheitsaspekte. Diskussion und Schlussfolgerung: Die inhaltliche Ausrichtung des Outcome-Assessments klinischer Studien zum RDS basiert hauptsächlich auf der Erhebung gastrointestinaler Symptome. In zukünftigen Studien sollten andere Gesundheitsaspekte des RDS wie begleitende psychologische Symptome oder soziale Auswirkungen der Gesundheitsstörung stärkere Berücksichtigung finden.

Abstract

Background: Patients with irritable bowel syndrome (IBS) report a significant impact of their symptoms on functional health. In outcome assessment of clinical studies on IBS, however, functional aspects other than gastrointestinal symptoms seem to be disregarded to a great extent. Aim: To analyze the content of outcome measures used in clinical IBS trials. Methods: A systematic review was performed in terms of a quantitative content analysis using the International Classification of Functioning, Disability and Health (ICF) as a coding scheme. Outcome measures were selected from all randomized controlled trials on IBS published in PubMed from the beginning to April 2002. From the outcome measures pre-specified text passages, so-called coding units, were extracted and linked to the ICF. A coding unit had to describe a single health aspect or an internal or external factor with an impact on health. If the outcome measure was a test the goal of the test was semantically implicated. Only second-level ICF categories contained in the outcome assessment of at least 10 % of the studies were considered. All steps of the review were performed by three independent raters. Results: 99 studies were included. Single items were used as outcome measures in 88, clinical and paraclinical tests in 42 and questionnaires in 24 studies. Ninety percent of the coding units (n = 2271) could be linked to the ICF. ICF categories describing gastrointestinal symptoms were considered in the outcome assessment of 37 to 85 studies depending on the type of content compared to extra-gastrointestinal symptoms in 10 to 22 studies. Health information of ICF components other than “body functions” was scarcely included. Clear secular trends for individual ICF categories could not be found. Only a single IBS-specific questionnaire considered health information other than gastrointestinal symptoms. Discussion and conclusion: Outcome assessment of clinical IBS studies is mainly based on gastrointestinal symptoms. The assessment of other health aspects like comorbid psychological symptoms or social consequences of the disease seems to be similarly important and should be considered in future trials. This would also facilitate the understanding of IBS as a biopsychosocial health condition, both in matters of aetiology and consequences.

Schlüsselwörter

Reizdarmsyndrom - Outcome-Assessment - systematischer Review - Inhaltsanalyse - ICF

Key words

Irritable bowel syndrome - outcome assessment - systematic review - content analysis - ICF

References

• 1 Thompson W G, Longstreth G F, Drossman D A, Heaton K W, Irvine E J, Muller-Lissner S A. Functional bowel disorders and functional abdominal pain.  Gut. 1999;  45, Suppl 2 II43-II47
• 2 Drossman D A, Corraziari E, Talley N J, Thompson W, Whitehead W E. Rome II. The Functional Gastrointestinal Disorders. Diagnosis, Pathophysiology and Treatment: A Multinational Consensus. 2nd ed. Mc Lean, VA; Degnon Associates 2000
• 3 Camilleri M. Management of the irritable bowel syndrome.  Gastroenterology. 2001;  120 (3) 652-668
• 4 Drossman D A. The functional gastrointestinal disorders and the Rome II process.  Gut. 1999;  45, Suppl 2 II1-II5
• 5 Folks D G. The interface of psychiatry and irritable bowel syndrome.  Curr Psychiatry Rep. 2004;  6 (3) 210-215
• 6 Lackner J M, Quigley B M, Blanchard E B. Depression and abdominal pain in IBS patients: the mediating role of catastrophizing.  Psychosom Med. 2004;  66 (3) 435-441
• 7 Vandvik P O, Wilhelmsen I, Ihlebaek C, Farup P G. Comorbidity of irritable bowel syndrome in general practice: a striking feature with clinical implications.  Aliment Pharmacol Ther. 2004;  20 (10) 1195-1203
• 8 Tillisch K, Labus J S, Naliboff B D, Bolus R, Shetzline M, Mayer E A. et al . Characterization of the alternating bowel habit subtype in patients with irritable bowel syndrome.  Am J Gastroenterol. 2005;  100 (4) 896-904
• 9 Talley N J, Zinsmeister A R, Dyke C Van, Melton 3rd  L J. Epidemiology of colonic symptoms and the irritable bowel syndrome.  Gastroenterology. 1991;  101 (4) 927-934
• 10 Heaton K W, O'Donnell L J, Braddon F E, Mountford R A, Hughes A O, Cripps P J. Symptoms of irritable bowel syndrome in a British urban community: consulters and nonconsulters.  Gastroenterology. 1992;  102 (6) 1962-1967
• 11 Jones R, Lydeard S. Irritable bowel syndrome in the general population.  BMJ. 1992;  304 (6819) 87-90
• 12 Drossman D A, Li Z, Andruzzi E, Temple R D, Talley N J, Thompson W G. et al . U.S. householder survey of functional gastrointestinal disorders. Prevalence, sociodemography, and health impact.  Dig Dis Sci. 1993;  38 (9) 1569-1580
• 13 Kay L, Jorgensen T, Jensen K H. The epidemiology of irritable bowel syndrome in a random population: prevalence, incidence, natural history and risk factors.  J Intern Med. 1994;  236 (1) 23-30
• 14 Agreus L, Svardsudd K, Nyren O, Tibblin G. Irritable bowel syndrome and dyspepsia in the general population: overlap and lack of stability over time.  Gastroenterology. 1995;  109 (3) 671-680
• 15 Zuckerman M J, Guerra L G, Drossman D A, Foland J A, Gregory G G. Comparison of bowel patterns in Hispanics and non-Hispanic whites.  Dig Dis Sci. 1995;  40 (8) 1763-1769
• 16 Camilleri M, Williams D E. Economic burden of irritable bowel syndrome. Proposed strategies to control expenditures.  Pharmacoeconomics. 2000;  17 (4) 331-338
• 17 Weber F H, McCallum R W. Clinical approaches to irritable bowel syndrome.  Lancet. 1992;  340 (8833) 1447-1452
• 18 Lynn R B, Friedman L S. Irritable bowel syndrome.  N Engl J Med. 1993;  329 (26) 1940-1945
• 19 Lynn R B, Friedman L S. Irritable bowel syndrome. Managing the patient with abdominal pain and altered bowel habits.  Med Clin North Am. 1995;  79 (2) 373-390
• 20 Drossman D A, Whitehead W E, Camilleri M. Irritable bowel syndrome: a technical review for practice guideline development.  Gastroenterology. 1997;  112 2120-2137
• 21 Inadomi J M, Fennerty M B, Bjorkman D. Systematic review: the economic impact of irritable bowel syndrome.  Aliment Pharmacol Ther. 2003;  18 671-682
• 22 Sandler R S, Everhart J E, Donowitz M, Adams E, Cronin K, Goodman C. et al . The burden of selected digestive diseases in the United States.  Gastroenterology. 2002;  122 (5) 1500-1511
• 23 Whitehead W E, Burnett C K, Cook E W, Taub E. Impact of irritable bowel syndrome on quality of life.  Dig Dis Sci. 1996;  47 (11) 2248-2253
• 24 Gralnek I M, Hays R D, Kilbourne A, Naliboff B, Mayer E A. The impact of irritable bowel syndrome on health-related quality of life.  Gastroenterology. 2000;  119 (3) 654-660
• 25 Porcelli P. Psychological abnormalities in patients with irritable bowel syndrome.  Indian J Gastroenterol. 2004;  23 (2) 63-69
• 26 Akehurst R, Kaltenthaler E. Treatment of irritable bowel syndrome: a review of randomised controlled trials.  Gut. 2001;  48 272-282
• 27 World Health Organization .International Classification of Functioning, Disability and Health. Geneva; WHO 2001
• 28 Brockow T, Cieza A, Kuhlow H, Sigl T, Franke T, Harder M. et al . Identifying the concepts contained in outcome measures of clinical trials on musculoskeletal disorders and chronic widespread pain using the International Classification of Functioning, Disability and Health as a reference.  J Rehabil Med. 2004;  36, Suppl 44 30-36
• 29 Brockow T, Duddeck K, Geyh S, Schwarzkopf S, Weigl M, Franke T. et al . Identifying the concepts contained in outcome measures of clinical trials on breast cancer using the International Classification of Functioning, Disability and Health as a reference.  J Rehabil Med. 2004;  36, Suppl 44 43-48
• 30 Brockow T, Wohlfahrt K, Hillert A, Geyh S, Weigl M, Franke T. et al . Identifying the concepts contained in outcome measures of clinical trials on depressive disorders using the International Classification of Functioning, Disability and Health as a reference.  J Rehabil Med. 2004;  36, Suppl 44 49-55
• 31 Geyh S, Kurt T, Brockow T, Cieza A, Ewert T, Omar Z. et al . Identifying the concepts contained in outcome measures of clinical trials on stroke using the International Classification of Functioning, Disability and Health as a reference.  J Rehabil Med. 2004;  36, Suppl 44 56-62
• 32 Wolff B, Cieza A, Parentin A, Rauch A, Sigl T, Brockow T. et al . Identifying the concepts contained in outcome measures of clinical trials on four internal disorders using the International Classification of Functioning, Disability and Health as a reference.  J Rehabil Med. 2004;  36, Suppl 44 37-42
• 33 Manning A P, Thompson W G, Heaton K W, Morris A F. Towards positive diagnosis of the irritable bowel.  Br Med J. 1978;  2 (6138) 653-654
• 34 Thompson W G, Dotevall G, Drossmann D A. Irritable bowel syndrome: guidelines for the diagnosis.  Gastroenterol Int. 1989;  2 92-95
• 35 Thompson W, Creed F, Drossmann D. Functional bowel disorders and functional abdominal pain.  Gastrointest J. 1992;  5 75-91
• 36 Drossmann D, Richter J E, Talley N J, Thompson W, Corraziari E, Whitehead W E. The Functional Gastrointestinal Disorders: Diagnosis, Pathophysiology and Treatment. 1^st ed. Boston; Little, Brown and Company 1994
• 37 Weber R P. Basic Content Analysis. 2^nd ed. Newbury Park; Sage University Paper 1990
• 38 Crown S, Crisp A H. A short diagnostic self-rating scale for psychoneurotic patients: The Middlesex Hospital Questionnaire (M.H.Q.).  Brit J Psychiat. 1966;  112 917-923
• 39 Cieza A, Brockow T, Ewert T, Amman E, Kollerits B, Chatterji S. et al . Linking health-status measurements to the International Classification of Functioning, Disability and Health.  J Rehabil Med. 2002;  34 205-210
• 40 Svedlund J, Sjodin I, Ottosson J O, Dotevall G. Controlled study of psychotherapy in irritable bowel syndrome.  Lancet. 1983;  2 (8350) 589-592
• 41 Irritable colon syndrome treated with an antispasmodic drug.  Practitioner. 1976;  217 (1298) 276-280
• 42 Soltoft J, Krag B, Gudmand-Hoyer E, Kristensen E, Wulff H R. A double-blind trial of the effect of wheat bran on symptoms of irritable bowel syndrome.  Lancet. 1976;  1 (7954) 270-272
• 43 Longstreth G F, Fox D D, Youkeles L, Forsythe A B, Wolochow D A. Psyllium therapy in the irritable bowel syndrome. A double-blind trial.  Ann Intern Med. 1981;  95 (1) 53-56
• 44 Cook I J, Irvine E J, Campbell D, Shannon S, Reddy S N, Collins S M. Effect of dietary fiber on symptoms and rectosigmoid motility in patients with irritable bowel syndrome. A controlled, crossover study.  Gastroenterology. 1990;  98 (1) 66-72
• 45 Hahn B A, Kirchdoerfer L J, Fullerton S, Mayer E. Evaluation of a new quality of life questionnaire for patients with irritable bowel syndrome.  Aliment Pharmacol Ther. 1997;  11 547-552
• 46 Schwetz I, Bradesi S, Mayer E A. Current insights into the pathophysiology of irritable bowel syndrome.  Curr Gastroenterol Rep. 2003;  5 (4) 331-336
• 47 Schwetz I, Bradesi S, Mayer E A. The pathophysiology of irritable bowel syndrome.  Minerva Med. 2004;  95 (5) 419-426
• 48 Delvaux M. Alterations of sensorimotor functions of the digestive tract in the pathophysiology of irritable bowel syndrome.  Best Pract Res Clin Gastroenterol. 2004;  18 (4) 747-771
• 49 Bercik P, Verdu E F, Collins S M. Is irritable bowel syndrome a low-grade inflammatory bowel disease?.  Gastroenterol Clin North Am. 2005;  34 (2) 235-245, vi-vii
• 50 Camilleri M. Mechanisms in IBS: something old, something new, something borrowed.  Neurogastroenterol Motil. 2005;  17 (3) 311-316
• 51 Quigley E M. Disturbances of motility and visceral hypersensitivity in irritable bowel syndrome: biological markers or epiphenomenon.  Gastroenterol Clin North Am. 2005;  34 (2) 221-233, vi
• 52 Weigl M, Cieza A, Harder M, Geyh S, Amann E, Kostanjsek N. et al . Linking osteoarthritis-specific health-status measures to the International Classification of Functioning, Disability, and Health (ICF).  Osteoarthritis Cartilage. 2003;  11 (7) 519-523
• 53 Stamm T A, Cieza A, Machold K P, Smolen J S, Stucki G. Content comparison of occupation-based instruments in adult rheumatology and musculoskeletal rehabilitation based on the International Classification of Functioning, Disability and Health.  Arthritis Rheum. 2004;  51 (6) 917-924
• 54 Borchers M, Cieza A, Sigl T, Kollerits B, Kostanjsek N, Stucki G. Content comparison of osteoporosis-targeted health status measures in relation to the International Classification of Functioning, Disability and Health (ICF).  Clin Rheumatol. 2005;  24 (2) 139-144
• 55 Sigl T, Cieza A, Heijde D van der, Stucki G. ICF-based comparison of disease-specific instruments measuring physical functional ability for ankylosing spondylitis. Ann Rheum Dis 2005 0 200402718 [Epub ahead of print]
• 56 Stamm T A, Cieza A, Coenen M, Machold K P, Nell V P, Smolen J S. et al . Validating the International Classification of Functioning, Disability and Health Comprehensive Core Set for Rheumatoid Arthritis from the patient perspective: A qualitative study.  Arthritis Rheum. 2005;  53 (3) 431-439
• 57 Weigl M, Cieza A, Andersen C, Kollerits B, Amann E, Stucki G. Identification of relevant ICF categories in patients with chronic health conditions: a Delphi exercise.  J Rehabil Med. 2004;  36, Suppl 44 12-21
• 58 Krippendorff K. Content Analysis. An introduction to its methodology. 2^nd ed. Teller Road; Sage Publications 2004
• 59 Li Cai B A. Assessing co-termination in the unitizing phase of content analysis: a multi-response randomized blocks permutation approach. Master Examination. Columbus, OH; Ohio State University 2003
• 60 Holsti O R. Content Analysis for the Social Sciences and Humanities. Reading, Mass; Addison Wesley Publishing Company USA 1969
• 61 Cohen J. A coefficient of agreement for nominal scales.  Educ Psychol Meas. 1960;  20 37-46
• 62 Fleiss J L, Nee J CM, Landis J R. Large sample variance of kappa in the case of different sets of raters.  Psychol Bull. 1979;  86 974-977
• 63 Daltroy L H. Common problems in using, modifying, and reporting on classic measurement instruments.  Arthritis Care Res. 1997;  10 (6) 441-447
• 64 Mangel A W, Hahn B A, Heath A T. Adequate relief as an endpoint in clinical trials in irritable bowel syndrome.  J Int Med Res. 1998;  26 76-81