To the Editor:

We read with great interest the article by Dr. Duprée A et al. [1]. This retrospective study identified that super-super-obesity should not be considered as a limiting factor for bariatric surgery outcome; however, the patients’ age, surgeries prior to the bariatric procedure, and comorbidities must be considered prior to bariatric surgical treatment. Herein, we would like to raise the following comments:

In this study, among three groups of patients, significant differences existed in patients’ characteristics, including age, sex ratio, steatosis hepatis, et al. (all P < 0.05). These confounding variables among the three groups suggested an unbalanced enrollment. Besides, despite a couple of confounding variables among the three groups, only the univariable analyses are used to draw the conclusion. In fact, propensity score matching (PSM) analysis has been generally applied in observational studies, which could better balance the potential risk factors between groups and evaluates the extent of balanced match in a measurable approach [2, 3]. This method could be used in further studies based on the valuable data in the present study.

In addition, the number of variables of characteristics investigated in this study seemed insufficient. Perioperative transfusion and loss, ECOG performance status, ASA score, tobacco abuse, and preoperative albumin level [4, 5], which could exert an impact upon surgeons’ decisions on the type of surgery as well as perioperative short-term outcome in patients undergoing bariatric surgery, have not been listed as variables. Therefore, the reliability and accuracy of the conclusions of this study need further evaluation.

In summary, we deeply appreciate the authors’ work and believe that the study has a great quality; that is, being derived from a large-scale retrospective study. We suggested that PSM analysis be used in this study for the further confirmation of the real association between super-super-obesity and perioperative short-term outcome in patients undergoing bariatric surgery. Meanwhile, some potentially important variables on patients’ baseline characteristics need to be investigated in this study. Clarification regarding the abovementioned omission would greatly solidify the conclusions of the study by Dr. Duprée A et al. [1].