Evaluation of the psychometric properties of self‐reported weight stigma measures: A systematic literature review

Objective Conceptualisation and measurement of weight stigma varies across available studies assessing those affected. This paper aims to systematically review the psychometric properties of available self-reported measures of weight stigma. Method Studies exploring the development and/or validation of weight stigma measures were identified through systematically searching Medline, CINAHL, PsycINFO, Embase, Web of Science, and Scopus databases. The Consensus-based Standards of Health Measurement Instruments (COSMIN) checklist was used to assess the psychometric properties of measures. Results Thirty-six articles, reporting 18 different weight stigma measures, were included. For most included measures, measure development and content validity have not been assessed/reported. Structural validity, internal consistency, and hypothesis testing were the most commonly assessed/reported psychometric properties. High-quality ratings were given only for these properties. Most measures were rated as “indeterminate” and received an overall quality rating of “Very Low” as results were based on limited evidence. Conclusions Psychometric properties for published weight stigma measures have rarely been assessed/reported. The observed poor methodological quality for measure development, and limited content validity evidence, negatively impact the quality of evidence for the measures. There is a need for studies assessing the psychometric properties of existing weight stigma measures using COSMIN guidelines, and for a well-designed weight stigma measure informed by both theory and research

Psychometric evaluation of the IWQOL-Lite (Spanish version) when applied to a sample of obese patients awaiting bariatric surgery

Background Obesity may have an impact on key aspects of health-related quality of life (HRQOL). In this context, the Impact of Weight Quality of Life (IWQOL) questionnaire was the first scale designed to assess HRQOL. The aim of the present study was twofold: to assess HRQOL in a sample of Spanish patients awaiting bariatric surgery and to determine the psychometric properties of the IWQOL-Lite and its sensitivity to detect differences in HRQOL across groups. Methods Participants were 109 obese adult patients (BMI¿ 35 kg/m2) from Barcelona, to whom the following measurement instruments were applied: IWQOL-Lite, Depression Anxiety Stress Scales, Brief Symptom Inventory, and self-perception items. Results Descriptive data regarding the IWQOL-Lite scores obtained by these patients are reported. Principal components analysis revealed a five-factor model accounting for 72.05% of the total variance, with factor loadings being adequate for all items. Corrected itemtotal correlations were acceptable for all items. Cronbach"s alpha coefficients were excellent both for the subscales (0.880.93) and the total scale (0.95). The relationship between the IWQOLLite and other variables supports the construct validity of the scale. Finally, sensitivity analysis revealed large effect sizes when comparing scores obtained by extreme BMI groups. Conclusions This is the first study to report the application of the IWQOL-Lite to a sample of Spanish patients awaiting bariatric surgery and to confirm that the Spanish version of the instrument has adequate psychometric properties