ABSTRACT
BACKGROUND: The purpose of this study was to evaluate the measurement properties of the American Neurogastroenterology and Motility Society Gastroparesis Cardinal Symptom Index-Daily Diary, a patient-reported outcome instrument developed to meet US FDA recommendations for a symptom-based clinical trial endpoint in gastroparesis. The ANMS GCSI-DD assesses nausea, early satiety, postprandial fullness, and upper abdominal pain on a severity score from none (0) to very severe (4) and number of vomiting episodes during the past 24 hours. The composite score includes the first four symptoms, the core symptom score includes all five symptoms. METHODS: Seventy-one patients diagnosed with idiopathic or diabetic gastroparesis were recruited for a four-week observational study. Patients completed the ANMS GCSI-DD at home between Baseline and Week 4. Statistical analyses included confirmatory factor analysis, item response theory analysis, internal consistency, test-retest reliability, and construct and known-groups validity. KEY RESULTS: Unidimensionality for the composite and core symptom scores was supported, and items exhibited good fit. Internal consistency (Cronbach's alpha =0.85 and 0.83) and test-retest reliability were 0.89 and 0.88, for composite and core symptom scores, respectively. Convergent validity was supported by strong correlations with patient-reported and clinician measures. Baseline and Week 4 scores differed for three measures used to define disease severity status (P < 0.0001), supporting known-groups validity. CONCLUSIONS & INFERENCES: The ANMS GCSI-DD has excellent reliability and validity, supporting its use to assess symptom-based endpoints in gastroparesis clinical studies. Further analyses will be conducted using clinical trial data to ascertain treatment responsiveness and define a responder.
Subject(s)
Diabetes Complications/physiopathology , Gastroparesis/physiopathology , Nausea/physiopathology , Vomiting/physiopathology , Adult , Aged, 80 and over , Female , Gastroparesis/diagnosis , Gastroparesis/etiology , Humans , Male , Medical Records , Middle Aged , Psychometrics , Reproducibility of Results , Severity of Illness Index , Symptom Assessment , Young AdultABSTRACT
BACKGROUND: The American Neurogastroenterology and Motility Society Gastroparesis Cardinal Symptom Index-Daily Diary (ANMS GCSI-DD) was developed to meet Food and Drug Administration (FDA) recommendations for patient-reported outcome (PRO) endpoints in gastroparesis studies, including therapeutic trials. The current version of the ANMS GCSI-DD contains five items pertaining to nausea, early satiety, post-prandial fullness, upper abdominal pain, and vomiting. The specific aims of this study were to determine if the appropriate symptoms are included in the ANMS GCSI-DD and to assess the content validity in patients with idiopathic (IG) and diabetic gastroparesis (DG). METHODS: Patients diagnosed with IG or DG were recruited by five clinical sites in the United States for a cross-sectional, qualitative study involving one-on-one in-person concept elicitation and cognitive debriefing interviews. Concept elicitation included open-ended questions to elicit patients' symptoms and impacts of gastroparesis, while cognitive debriefing was designed to assess the comprehensiveness of the ANMS GCSI-DD and clarity of the instructions, items, and response scales. The interviews were audio-recorded and transcribed. Transcripts were analyzed using a content analysis approach with ATLAS.ti. RESULTS: Of 25 patients interviewed, 15 (60%) had IG and 10 (40%) DG. Mean age of the sample was 42.3 years (range: 20-70 years), and most patients were female (n = 19, 76%) and white (n = 19, 76%). During concept elicitation, patients endorsed the following signs and symptoms as relevant and important to their condition: early satiety (n = 25, 100%), post-prandial fullness (n = 25, 100%), nausea (n = 22, 88%), upper abdominal pain (n = 18, 72%), vomiting (n = 15, 60%), and bloating (n = 11, 44%). Many patients (n = 20, 80%) experienced day-to-day symptom change. During cognitive debriefing, patients confirmed the ANMS GCSI-DD content was comprehensive and reflective of their gastroparesis experience. Patients could easily select a response option and describe how they arrived at their answers. Overall, patients found the instrument's instructions, recall period, items, and response options clear and understandable. CONCLUSIONS: The ANMS GCSI-DD was easily understood, found to contain the most important symptoms for patients with IG and DG, and no changes were recommended. Results support the content validity of the ANMS GCSI-DD for clinical trials and clinical care among IG or DG patients.
ABSTRACT
OBJECTIVE: The objective of this study was to develop a method for evaluating patient-relevant outcomes of interventions for preventing migraine attacks, followed by an assessment of the content validity of a new patient-reported outcome (PRO) instrument: the Migraine Functional Impact Questionnaire (MFIQ). BACKGROUND: The aim of preventive treatments for migraine is not only to reduce migraine frequency, but also to restore patients' ability to function and improve quality of life. METHODS: A multi-stage process based on best practice methods and regulatory guidelines for ensuring content validity of PRO instruments for evaluating treatment benefit was followed. Qualitative concept elicitation interviews conducted to understand the experiences of adults with migraine underpinned the development of the instrument. The initial stage included the development of a conceptual disease model (CDM) based on information from these interviews. This CDM was used to identify the concepts of interests (COI) to evaluate outcomes of preventive treatments. The results of the interviews were also used in stage 2, to develop a measurement framework for collecting data about these COI. In the third stage, existing instruments were reviewed for coverage of the concepts in the framework and evidence of concept elicitation to the point of saturation, to support content validity. In the fourth stage, an instrument was drafted to evaluate concepts in the framework, based on the qualitative data collected from the interviews. Following a review by clinical and translation experts, the new instrument was tested in adults with migraine in the fifth stage using 2 rounds of cognitive interviews, and was modified based on interview feedback. In the last stage, the instrument was linguistically adapted, using methods recommended for PRO instruments, to ensure conceptual equivalence of language versions for use in international studies. Each language version was tested in at least 5 native speakers using cognitive interviews. RESULTS: Results from the concept elicitation interviews suggested that migraine had an impact on various aspects of functioning. A conceptual framework for evaluating functional outcomes was developed for the concept selected based on a review of the CDM - physical and emotional functioning, every day activities, and social/leisure activities. Existing PROs lacked coverage of some concepts in the conceptual framework, had recall periods that were inappropriate for capturing the experience of COI or did not have evidence of content validity. A novel PRO instrument, the MFIQ, was developed to address these gaps. Cognitive interviews with 9 adults with migraine resulted in minor changes to the items of the MFIQ, and a final round of 8 interviews confirmed the changes were acceptable and supported its validity. The interviews conducted to test linguistic adaptations confirmed conceptual equivalence in the 25 countries evaluated. CONCLUSIONS: Development of the MFIQ followed best measurement practices to ensure content validity and followed regulatory guidelines for PRO instruments to evaluate benefits of treatments. The MFIQ was developed for use in clinical trials or clinical practice settings to track outcomes of preventive treatments that are most relevant to adults with migraine.
