Background: Quality of life (QoL) is considered to be the true measure for the effectiveness of a surgical procedure, but there are only a few validated instruments available for bariatric surgery. Therefore, a new diseasespecific 30-item instrument was created, which was called Bariatric Quality of Life (BQL) questionnaire.
Methods: To validate the BQL, we studied 133 patients after 4 different types of bariatric surgery. Initially, mean body mass index (BMI) was 47.2 +/-7.6 kg/m2 and mean age was 38.8 +/-11.0 years. At baseline, and 1, 6, and 12 months after surgery, patients filled in the BQL, the SF-12 (Short Form of SF-36 Health Survey), the GIQLI (Gastrointestinal Quality of Life Index), and the BAROS (Bariatric Analysis and Reporting Outcome System).
Results: Internal consistency of the BQL was found to be good, with Cronbach's alpha ranging between 0.71 and 0.86. Factor analyses suggested that the BQL included a highly consistent set of QoL items and a second part on co-morbidities and gastrointestinal symptoms. At the 12 months follow-up, the BQL was closely correlated to SF 12 (Pearson's r = 0.86), GIQLI (0.68), BAROS (0.71), and excess weight loss (0.55). Standardized effect sizes over time were larger for the BQL (1.39 and 1.58) than for the other instruments.
Conclusions: The BQL questionnaire is a validated instrument ready for clinical use.