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Table 3 Measures to evaluate symptoms, quality of life, and patient expectancy

From: Open-label versus double-blind placebo treatment in irritable bowel syndrome: study protocol for a randomized controlled trial

Scale Description
Primary outcome measure
Irritable Bowel Symptom Severity Scale (IBS-SSS) This 5-item questionnaire provides a simple way to scale IBS symptoms and the progress of the disease. Items consider pain, distension, bowel dysfunction, and quality of life/global wellbeing. Scores show good reliability and sensitivity to change
Secondary outcome measures
Symptom evaluation
IBS-Adequate Relief A single yes/no question makes up this simple global measure of symptom relief in the past week
IBS-Global Improvement A single question provides a measure of improvement in the past week using a 7-point scale
Daily Symptom Diary Questions regarding subject symptoms will be completed daily for the 7-day period prior to visit 2 and visit 3
Quality of life
Short Form-12 Health Survey (SF-12) This 12-item scale measures emotional and physical health and wellbeing
Psychosocial
Patient Health Questionnaire-8 (PHQ-8) An 8-item scale that is used as a diagnostic and severity measure for depressive disorders in clinical studies
Generalized Anxiety Disorder-7 (GAD-7) A 7-item scale that is used as a diagnostic and severity measure for anxiety disorders in clinical practice and research
Visceral Sensitivity Index A 15-item measure of gastrointestinal symptom-specific anxiety
Pain Catastrophizing Scale A scale that measures the tendency to magnify or exaggerate the seriousness of pain sensations
Five Factor Inventory A 60-item instrument that measures the “Big Five” dimensions of personality
Interpersonal Support Evaluation List Designed to measure perceptions of social support among individuals in the general population
Balanced Inventory of Desirable Reach Describes the tendency of respondents to answer questions that will be viewed favorably by others
Patient experience
Consultation and Relational Empathy Measure Assesses physician empathy and relational skills on 10 ordinal items, which are then summed
Expectancy Question “If I receive placebo/peppermint oil/no additional treatment, I expect my IBS symptoms to be: “(numerical rating scale running from zero “not improved at all” to 100 “completely improved”)