SF-6D Normative Values Among Patients Undergoing Bariatric Surgery: Results Based on Real-World Evidence from the Scandinavian Obesity Surgery Registry (SOReg)

Background The SF-6D index can be used to calculate quality-adjusted life years in economic evaluations, which is required by reimbursement agencies and national advisory bodies, including the Swedish ones. However, despite that SF-36 has been largely applied among patients undergoing bariatric surgery, almost no study has accessed the short form six-dimensions (SF-6D) after bariatric surgery. Aim To establish normative values for the SF-6D index among patients undergoing bariatric surgery. Materials and Methods All patients who received bariatric surgery in Sweden between 2011–01-01 and 2019–03-31 were obtained from the Scandinavian Obesity Surgery Registry (SOReg). Information includes patients’ sociodemographic characteristics, details regarding the procedure, and postsurgical conditions. The SF-36 is applied at baseline and at follow-up years 1, 2, and 5. The multiple sequential imputation method was applied to handle missingness on SF-6D items. Based on the UK tariff, the SF-6D preference scores were calculated. The normative values for the mean (SD) SF-6D index were reported by timepoint and surgical complications for men and women, respectively. Multivariate analyses were applied to investigate how the SF-6D index is associated with timepoint, controlling for age, sex, BMI, and comorbidities in a stepwise manner. Results The SF-6D index increased at 1 year relative to baseline and was roughly maintained at the same level at 2 years. The normative value of the SF-6D index can be used in economic evaluations for bariatric surgery. Graphical Abstract