Intersection of smoking, e-cigarette use, obesity, and metabolic and bariatric surgery: a systematic review of the current state of evidence.

BACKGROUND: Millions of Americans qualify for metabolic and bariatric surgery (MBS) based on the proportion of the population with severe obesity. Simultaneously, the use of electronic nicotine/non-nicotine delivery systems (ENDS) has become epidemic. OBJECTIVE: We conducted a timely systematic review to examine the impact of tobacco and ENDS use on post-operative health outcomes among MBS patients. METHODS: PRISMA guidelines were used as the search framework. Keyword combinations of either "smoking," "tobacco," "e-cigarette," "vaping," or "ENDS" and "bariatric surgery," "RYGB," or "sleeve gastrectomy" were used as search terms in PUBMED, Science Direct, and EMBASE. Studies published in English between January 1990 and June 2020 were screened. RESULTS: From the 3251 articles found, a total of 48 articles were included in the review. No articles described a relationship between ENDS and post-operative health outcomes in MBS patients. Seven studies reported smokers had greater post-MBS weight loss, six studies suggested no relationship between smoking and post-MBS weight loss, and one study reported smoking cessation pre-MBS was related to post-MBS weight gain. Perioperative use of tobacco is positively associated with several post-surgery complications and mortality in MBS patients. CONCLUSIONS: Combustible tobacco use among MBS patients is significantly related to higher mortality risk and complication rates, but not weight loss. No data currently is available on the impact of ENDS use in these patients. With ENDS use at epidemic levels, it is imperative to determine any potential health effects among patients with severe obesity, and who complete MBS.