Content validity of self-reports of excess skin after bariatric surgery: protocol for a Dutch cross-sectional study

Body contouring surgery (BCS) can be applied to reduce the physical and mental burden of excess skin after massive weight loss. Self-reported outcomes of patients are used to assess this burden and to evaluate the effectiveness of BCS. The aim of this study is to clarify what is reflected in self-reports of excess skin after bariatric surgery. We hypothesise that the self-reported burden of excess skin is associated with both objectively assessed excess skin and the disposition to experience negative emotions.

This cross-sectional study will include 68 outpatients presenting at a plastic surgery clinic with a request for BCS. Patients fill out two questionnaires (the BODY-Q and the Sahlgrenska Excess Skin Questionnaire (SESQ)) to measure the size and burden of excess skin as well as the Big Five Inventory (BFI) to measure the disposition towards negative emotionality. Anonymised photographs of excess skin will be rated independently by four plastic surgeons using the Pittsburgh Rating Scale (PRS) Rainbow Classification to establish the objective amount of excess skin. Multiple linear regression analyses will be performed to identify the association of BODY-Q and SESQ scores with objective appraisals of excess skin by plastic surgeons, negative emotionality and demographics. Interobserver agreement for PRS Rainbow Classification will be established by Fleiss' kappa.

Ethical approval was obtained from the regional medical ethics committee (METC; W20.258) and the institutional review board (Lokale Toetsing, St. Antonius Hospital in Nieuwegein, no. Z23.035). Informed consent of participants will be obtained. The results of this study will be submitted for publication in a peer-reviewed journal.