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Confirmatory psychometric evaluations of the Impact of Weight on Quality of Life–Lite Clinical Trials Version ( IWQOL‐Lite‐CT )
Author(s) -
Kolotkin Ronette L.,
Williams Valerie S. L.,
von Huth Smith Lisa,
Meincke Henrik Hjorth,
Qin Shanshan,
Williams Nicole,
Fehnel Sheri E.
Publication year - 2021
Publication title -
clinical obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 12
eISSN - 1758-8111
pISSN - 1758-8103
DOI - 10.1111/cob.12477
Subject(s) - medicine , psychosocial , cronbach's alpha , intraclass correlation , context (archaeology) , physical therapy , clinical trial , quality of life (healthcare) , construct validity , overweight , clinical psychology , psychometrics , obesity , psychiatry , paleontology , nursing , biology
Summary The Impact of Weight on Quality of Life–Lite Clinical Trials Version (IWQOL‐Lite‐CT) was developed to assess weight‐related physical and psychosocial functioning in the context of clinical trials. Data from two pivotal trials of once‐weekly subcutaneous semaglutide for the purpose of weight management (NCT03548935 and NCT03552757) were analysed to confirm the structure, reliability, validity, and responsiveness of the IWQOL‐Lite‐CT and evaluate the magnitude of meaningful within‐patient change in patients with overweight or obesity, with and without type 2 diabetes. Factor analyses and inter‐item correlations confirmed the IWQOL‐Lite‐CT structure and scoring algorithm. Each composite score (physical, physical function, psychosocial, and total) demonstrated excellent internal consistency (Cronbach's alphas ≥ 0.82) and test–retest reliability (intraclass correlation coefficients ≥ 0.85) in both trials. Patterns of cross‐sectional and longitudinal construct validity correlations were generally consistent with hypotheses. Each of the IWQOL‐Lite‐CT composites was able to discriminate between known groups. Effect sizes and paired t tests comparing IWQOL‐Lite‐CT scores at baseline and Week 68 were statistically significant for all composites in both trials ( P < 0.0001), providing strong support for the ability to detect change. Results of anchor‐based analyses supported responder thresholds ranging from 13.5 to 16.6 across composite scores. The IWQOL‐Lite‐CT, a comprehensive assessment of weight‐related functioning from the patient perspective, is appropriate for use in clinical trials evaluating the efficacy of new treatments for weight management.