The Dermatology Life Quality Index (DLQI) is a widely used health-related quality of life measure. However, little research has been conducted on its dimensionality. The objectives of the current study were to apply Rasch analysis to DLQI data to determine whether the scale is unidimensional, to assess its measurement properties, test the response format, and determine whether the measure exhibits differential item functioning (DIF) by disease (atopic dermatitis versus psoriasis), gender, or age group. The results show that there were several problems with the scale, including misfitting items, DIF by disease, age, and gender, disordered response thresholds, and inadequate measurement of patients with mild illness. As the DLQI did not benefit from the application of Rasch analysis in its development, it is argued that a new measure of disability related to dermatological disease is required. Such a measure should use a coherent measurement model and ensure that items are relevant to all potential respondents. The current use of the DLQI as a guide to treatment selection is of concern, given its inadequate measurement properties.

Background Non-alcoholic steatohepatitis (NASH) is a progressive form of non-alcoholic fatty liver disease characterized by excessive liver fat accumulation, inflammation, cell injury, and fibrosis. It is viewed as largely asymptomatic in its earlier (non-cirrhotic) stages, and information on the patient-perceived impact of NASH is scarce. Objective This study aimed to develop a NASH-specific patient-reported outcome (PRO) measure (NASH-CHECK) for use as a trial endpoint, using methods compliant with regulatory expectations. Methods A NASH conceptual model was developed based on the literature and clinical/patient expert review. The model guided concept elicitation (CE) interviews in patients with non-cirrhotic NASH recruited via a US tertiary care center. NASH-CHECK content was generated via thematic analysis of CE data and review by clinical/patient experts. Cognitive debriefing (CD) interviews with US patients evaluated content validity. Results The literature review confirmed that NASH impacts on functioning and health-related quality of life (HRQoL). Overall, 23 CE and 20 CD interviews were conducted. Key symptoms reported in CE interviews included pain in the upper-right abdomen ( n = 14), fatigue ( n = 18), poor sleep quality ( n = 12), impaired memory ( n = 13), and reduced focus ( n = 11); key HRQoL impacts included impaired physical functioning, reduced ability to conduct daily living tasks, reduced quality of relationships, low mood, anxiety, and self-consciousness. The 52-item first-draft NASH-CHECK was reduced to 31 items based on patient feedback on item relevance, acceptability, and comprehension. Conclusions The interviews revealed key symptoms and broad HRQoL impacts of NASH. As a disease-specific PRO measure assessing symptoms and HRQoL, the NASH-CHECK is relevant, comprehensive, and acceptable to patients and clinicians.

It is valid to conceptualize the functional impact of fatigue as unidimensional. The U-FIS is a reliable and valid questionnaire that will allow the measurement of this construct in clinical studies.

Clinicians and researchers can have confidence in scores obtained by respondents on the PRIMUS. The PRIMUS will aid the assessment of the impact of MS from the patient's perspective.

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BackgroundThe PRIMUS is a Multiple Sclerosis (MS)-specific suite of outcome measures including assessments of QoL (PRIMUS QoL, scored 0-22) and activity limitations (PRIMUS Activities, scored 0-30). The U-FIS is a measure of fatigue impact (scored 0-66). These measures have been fully validated previously using an MS sample with mixed diagnoses. The aim of the present study was to validate the measures further in a specifically Relapse Remitting MS (RRMS) sample and to provide preliminary evidence of the responder definitions (RD; also known as minimal important difference) for these instruments.MethodsData were derived from a multi-country efficacy trial of MS patients with assessments at baseline and 12 months. Baseline data were used to assess the internal reliability and validity of the measures. Both anchor-based and distribution-based approaches were employed for estimating RD. Anchor-based estimates were based on published RD values for the EQ-5D and were assessed for those improving and deteriorating separately. Distribution-based estimates were based on standard error of measurement (SEM), change score equivalent to 0.30, and change score equivalent to 0.50, effect sizes (ES).ResultsThe sample included 911 RRMS patients (67.3% female, age mean (SD) 36.2 (8.4) years, duration of MS mean (SD) 4.8 (5.2) years). Results showed that the PRIMUS and U-FIS had good internal consistency. Appropriate correlations were observed with comparator instruments and both measures were able to distinguish between participants based on Expanded Disability Status Scale scores and time since diagnosis. The anchor-based and distribution-based RD estimates were: PRIMUS Activities range = 1.2-2.3, PRIMUS QoL range = 1.0-2.2, and U-FIS range = 2.4-7.0.ConclusionsThe results show that the PRIMUS and U-FIS are valid instruments for use with RRMS patients. The analyses provide preliminary information on how to interpret scores on the scales. These data will be useful for assessing treatment efficacy and for powering clinical studies.Trial Reference NumberClinicalTrials.gov Identifier NCT00340834.

The CLIQ, the first CD-specific PRO, is unidimensional and has excellent psychometric properties. It should prove to be a valuable tool for evaluating the impact of CD and its treatment from the patients' perspective.

The U-FIS is a practical new measure of the impact of fatigue. It was successfully adapted into eight new languages to broaden availability for researchers. Psychometric analyses indicated that the new language versions were unidimensional and reproducible with promising construct validity.