Long-Term Effects of Bariatric Surgery on Type II Diabetes, Hypertension and Hyperlipidemia: A Meta-Analysis and Meta-Regression Study with 5-Year Follow-Up

Background The first aim of the study was to estimate weight loss and major modifiable risk factors after bariatric surgery. The second aim was to investigate the relationship between the reduction in cardiovascular risk and weight loss over time. Methods A random effect of meta-analysis and dose-response meta-regression was used to evaluate weight loss and the risk of type II diabetes, hypertension and hyperlipidemia, 2-5 years after surgery. Results A search of the literature led to the selection of 22 papers. The body mass index (BMI) at the end of the observation period was 31.7 (95 % CI=29.7-33.7; I-2=6 %). The risk of type II diabetes, hypertension and hyperlipidemia decreased after bariatric surgery, with relative risks of, respectively, 0.33 (95 % CI=0.26-0.41; I-2=42 %), 0.54 (95 % CI=0.46-0.64; I-2=68 %) and 0.33 (95 % CI=0.22-0.46; I-2=74 %). Nonlinear meta-regression revealed different patterns of risk: Hypertension risk reached a minimum when the BMI fell 10 units. The risks of all cardiovascular outcomes reached a plateau, 20-40 months after surgery. Conclusions The reduction in arterial hypertension reached a nadir earlier than the risk of diabetes and hyperlipidemia, thus indicating a possible link between weight reduction and positive hemodynamic effects.