Early impact of bariatric surgery on type II diabetes, hypertension, and hyperlipidemia: a systematic review, meta-analysis and meta-regression on 6,587 patients.

Background: This study aims to evaluate the 12-24-month impact of bariatric surgery on the foremost modifiable traditional risk factors of cardiovascular disease.

Methods: A systematic review and meta-analysis of prospective interventional studies reporting the most commonly performed laparoscopic surgical procedures, i.e., Roux-en-Y gastric bypass (RYGB), adjustable gastric banding (AGB), and cardiovascular risk reduction after surgery.

Results: The bibliographic research conducted independently by two authors yielded 18 records. When looking at RYGB and AGB separately, we observed a relevant heterogeneity (I (2) index ≥87 %) when BMI reduction was considered as the main outcome. When hypertension, type II diabetes, and hyperlipidemia risk reduction was estimated, a highly significant beneficial effect was found. The risk reduction was 0.33 [0.26; 0.42] for type II diabetes, 0.52 [0.42; 0.64] for hypertension, and 0.39[0.27; 0.56] for hyperlipidemia (P < 0.0001 for all outcomes considered). When looking at surgical technique separately, a higher but not statistically significant risk reduction for all outcomes considered was found. Results from the meta-regression approach showed an inverse relation between cardiovascular risks and BMI reduction.

Conclusions: The present study showed an overall reduction of cardiovascular risk after bariatric surgery. According to our analysis a BMI reduction of 5 after surgery corresponds to a type II diabetes reduction of 33 % (as reported by Peluso and Vanek (Nutr Clin Pract 22(1):22-28, 2007); SAS Institute Inc., (2000-2004)), a hypertension reduction of 27 % (as reported by Buchwald and Oien (Obes Surg 23(4):427-436, 2013); Valera-Mora et al. (Am J Clin Nutr 81(6):1292-1297, 2005)), and a hyperlipidemia reduction of 20 %(as reported by Adams et al. (JAMA 308(11):1122-31, 2012)); Alexandrides et al. (Obes Surg 17(2):176-184, 2007). In summary, our study showed that laparoscopic bariatric surgery is an effective therapeutic option to reduce the cardiovascular risk in severe obese patients.