Content Validity and Psychometric Evaluation of the Crohn's Symptom Severity (CSS) Questionnaire in Patients with Moderately to Severely Active Crohn's Disease.

Introduction: Individuals living with Crohn's disease (CD) experience burdensome symptoms. As such, it is important to measure CD symptom severity in clinical research. The goal of this study was to evaluate the content validity, psychometric performance, and score interpretability of a new patient-reported instrument, the Crohn's Symptom Severity (CSS) questionnaire, among adolescents and adults with moderately to severely active CD.

Content Validity and Psychometric Evaluation of the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue) in Patients with Crohn's Disease and Ulcerative Colitis.

Background: Patients with Crohn's disease (CD) or ulcerative colitis (UC) frequently experience fatigue, although it is often overlooked in medical research and practice.

Aims: To explore patients' experience of fatigue and evaluate content validity, psychometric properties, and score interpretability of the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue) in patients with CD or UC.

Methods: Concept elicitation and cognitive interviews were conducted with participants aged ≥ 15 years with moderately-to-severely active CD (N = 30) or UC (N = 33).

Development and content validity of the Barth Syndrome Symptom Assessment (BTHS-SA) for adolescents and adults.

Background: Barth Syndrome (BTHS) is a rare genetic disorder that presents as a complex of debilitating symptoms and reduced life expectancy. Well-developed, BTHS-specific assessments measuring primary signs and symptoms of BTHS are not currently available, making it difficult to evaluate treatment effects in BTHS clinical studies. The objective of this research was to develop symptom-focused patient-reported outcome (PRO) measures for use in clinical studies with adolescents and adults with BTHS.

Development of a Patient-Reported Outcome Questionnaire to Evaluate Primary Mitochondrial Myopathy Symptoms: The Primary Mitochondrial Myopathy Symptom Assessment.

Objectives: Primary mitochondrial myopathy (PMM) is a genetic condition characterized by life-limiting symptoms such as muscle weakness, fatigue, and pain. Because these symptoms are best reported by individuals with PMM, the objective of this qualitative research study was to develop a PMM-specific patient-reported outcome (PRO) questionnaire.

Method: Individuals with PMM were interviewed, identifying the most salient symptoms of PMM and assessing the resulting questionnaire's relevance and comprehensibility.

Understanding the life experience of Barth syndrome from the perspective of adults: a qualitative one-on-one interview study.

Background: Barth syndrome (BTHS, OMIM 302060) is a rare, life-threatening, x-linked genetic disorder that occurs almost exclusively in males and is characterized by cardiomyopathy, neutropenia, skeletal muscle myopathy primarily affecting larger muscles, and shorter stature in youth. A greater number of individuals with BTHS are now surviving into adulthood due to advancements in diagnosis and disease management. Given these improvements in life expectancy, understanding the disease experience over time has become increasingly important to individuals with the condition, treatment developers, and regulatory agencies.