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This study compared the measurement properties of the Moorehead-Ardelt quality of life questionnaire-II (MAQOL-II) and the BODY-Q, to determine which was more suitable for measuring patient-reported outcome (PRO) in Danish bariatric surgery (BS) and body contouring surgery (BC) patients. We examined content validity against the COSMIN guidelines and compared psychometric performance using Rasch measurement theory methods and criteria. MAQOL-II data were obtained from the Danish Bariatric Surgery Database from September 2010 to November 2017, and BODY-Q data were collected from June 2015 to March 2018. The MAQOL-II failed to meet recommended standards for content validity, while all criteria were met for the BODY-Q. A total of 16 965 MAQOL-II and 2259 BODY-Q assessments were obtained. A random sample was selected from the MAQOL-II dataset to match the BODY-Q sample. Psychometrically, the BODY-Q performed better than the MAQOL-II. For example, Cronbach's α was 0.82 for the MAQOL-II vs ≥0.90 for all BODY-Q scales. Fifty percent (3/6) of MAQOL-II items had disordered thresholds, while all BODY-Q items had ordered thresholds (123/123). Poor item fit was revealed for 17% (1/6) of MAQOL-II and 8% (10/123) of BODY-Q items. For scale reliability, person separation index was 0.79 for the MAQOL-II and 0.88 (0.81-0.93) for the BODY-Q. In conclusion, the MAQOL-II does not meet today's standards for a rigorously developed PRO measure. The BODY-Q, on the other hand, gives substantial, accurate and interpretable measurement and should be recommended for use in PRO in BS and BC patients., (© 2020 World Obesity Federation.)

Background: Stretch marks are common permanent dermal lesions that can cause psychosocial distress. A number of treatment modalities are available, with the majority targeted towards collagen production., Objectives: To develop and field test a new BODY-Q scale to measure appearance of stretch marks in order to provide a means to incorporate the patient perspective into future treatment studies., Methods: We previously described the development of the BODY-Q conceptual framework, which involved a literature review, 63 patient interviews, 22 cognitive interviews and input from 9 experts, and the international field-test study that involved 403 weight loss and 331 body contouring patients. To develop the Stretch Marks scale, we reexamined appearance codes from the original interviews. The scale was field tested in an international study. Rasch measurement theory (RMT) analysis was used to refine the scale and examine measurement properties., Results: The Stretch Marks scale was completed by 630 participants, who provided 774 assessments. After dropping 3 items, the data fit the Rasch model (P = 0.56). Items (eg, length, width, amount, location, up close) mapped out a well-targeted clinical hierarchy. All items had ordered thresholds and good item fit. There was no evidence of differential item functioning (bias) by gender, age group or language (English vs Danish). The scale evidenced high reliability (ie, person separation index = 0.94, Cronbach's alpha = 0.97). For construct validity, the mean score correlated with the total number of body areas with stretch marks, higher BMI before bariatric surgery, and other BODY-Q scales., Conclusions: This scale could be used to measure the impact of innovative treatments for stretch marks.