Validation of a new measure of quality of life in obesity trials: Impact of Weight on Quality of Life‐Lite Clinical Trials Version

• Published in: Clinical obesity Vol. 9; no. 3; pp. e12310 - n/a
• Main Authors: Kolotkin, Ronette L., Williams, Valerie S. L., Ervin, Claire M., Williams, Nicole, Meincke, Henrik H., Qin, Shanshan, Huth Smith, Lisa, Fehnel, Sheri E.
• Format: Journal Article
• Language: English
• Published: Chichester, UK Blackwell Publishing Ltd 01.06.2019; Wiley Subscription Services, Inc
• Subjects: Adult; Aged; Body mass; Body Mass Index; Body Weight; Body weight loss; Clinical trials; Correlation coefficients; Diabetes mellitus (non-insulin dependent); Female; Glucagon-Like Peptides - therapeutic use; health‐related quality of life; Humans; Impact of Weight on Quality of Life‐Lite (IWQOL‐Lite); Impact of Weight on Quality of Life‐Lite Clinical Trials Version (IWQOL‐Lite‐CT); Male; Middle Aged; Obesity; Obesity - drug therapy; Obesity - physiopathology; Obesity - psychology; Original; Original s; patient functioning; psychometric validation; Psychometrics - methods; Quality of Life; Regulatory agencies; Social interactions; Surveys and Questionnaires; Weight Loss; Impact of Weight on Quality of Life-Lite Clinical Trials Version (IWQOL-Lite-CT); health-related quality of life; psychometric validation; patient functioning; Impact of Weight on Quality of Life-Lite (IWQOL-Lite)
• ISSN: 1758-8103; 1758-8111
• DOI: 10.1111/cob.12310

The Impact of Weight on Quality of Life‐Lite (IWQOL‐Lite) is widely used in evaluations of weight‐loss interventions, including pharmaceutical trials. Because this measure was developed using input from individuals undergoing intensive residential treatment, the IWQOL‐Lite may include concepts not relevant to clinical trial populations and may be missing concepts that are relevant to these populations. An alternative version, the IWQOL‐Lite Clinical Trials Version (IWQOL‐Lite‐CT), was developed and validated according to the US Food and Drug Administration's (FDA's) guidance on patient‐reported outcomes. Psychometric analyses were conducted to validate the IWQOL‐Lite‐CT using data from two randomized trials (NCT02453711 and NCT02906930) that included individuals with overweight/obesity, with and without type 2 diabetes. Additional measures included the SF‐36, global items, weight and body mass index. The IWQOL‐Lite‐CT is a 20‐item measure with two primary domains (Physical [seven items] and Psychosocial [13 items]). A five‐item Physical Function composite and Total score were also supported. Cronbach's alpha and intraclass correlation coefficients exceeded 0.77 at each time point; patterns of construct validity correlations were consistent with hypotheses; and scores demonstrated treatment benefit. The IWQOL‐Lite‐CT is appropriate for assessing weight‐related physical and psychosocial functioning in populations commonly targeted for obesity clinical trials. Qualification from the FDA is being sought for use of the IWQOL‐Lite‐CT in clinical trials to support product approval and labelling claims.