ORIGINAL CONTRIBUTIONS Effects of Bariatric Surgery on HDL Cholesterol Idoia Genua 1 & Analia Ramos 1 & Francisca Caimari 1 & Carmen Balagué 2 & Jose Luis Sánchez-Quesada 3 & Antonio Pérez 1,4,5 & Inka Miñambres 1,4 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract Background Low levels of high-density lipoprotein cholesterol (HDLc) are independent predictive factors of coronary heart disease. Bariatric surgery increases HDLc concentration, but the chronology and predictors of this improvement in HDLc levels are not well-established. The aim of the present study was to analyse the changes over time in HDLc concentrations after bariatric surgery and to determine the predictors of their increase. Subjects and Methods This was a retrospective, observational study. The medical records of patients who had undergone bariatric surgery at a tertiary care hospital between January 2007 and March 2015 were reviewed. Patients who underwent revisional surgery or were treated with fibrates were excluded from the analysis. Results A total of 185 patients were included in the study. Follow-up rates were as follows: 87% (year 2) and 28% (year 5). At postoperative month 3, HDLc levels decreased significantly versus baseline (- 11.1%; p = 0.000), at which point they began to rise, reaching their maximum level 2 years after bariatric surgery (26.2% increase from baseline; p = 0.000). The increase in HDLc concentration 2 years after surgery correlated with the preoperative HDLc level (r = - 0.292, p = 0.001), and it was greater in patients who underwent sleeve gastrectomy versus gastric bypass (0.36 ± 0.4 vs. 0.18 ± 0.4 mmol/L, respectively; p = 0.018). Conclusion Bariatric surgery has a beneficial effect on HDLc levels. The maximum increase in postoperative HDLc concentra- tions is observed 2 years after surgery. Preoperative HDLc and the type of surgery are both significant predictors of the maximum increase in HDLc levels. Keywords Bariatric surgery . Lipid profile . HDL cholesterol Introduction Obesity is associated with an increased risk of cardiovascular mortality [1]. Bariatric surgery lowers this risk [2–6] by re- ducing the inflammatory milieu that is characteristic of obesity and by improving the metabolic comorbidities—including quantitative and functional changes in the lipoprotein profile [7]—associated with obesity, among others. Atherogenic dyslipidaemia in patients with obesity is char- acterized by increased serum concentrations of triglycerides, decreased high-density lipoprotein cholesterol (HDLc) levels and by the presence of small, dense low-density lipoprotein cholesterol (LDLc) particles [8]. Low HDLc levels are an independent predictor of the risk of coronary heart disease and there is a strong, inverse association between HDLc levels and the rates of incident coronary heart disease events [9] . Bariatric surgery has a beneficial effect on lipid profile [10], including an increase in HDLc concentrations [11–14]. Antonio Pérez and Inka Miñambres contributed equally to this work * Inka Miñambres iminambres@santpau.cat Antonio Pérez aperez@santpau.cat 1 Endocrinology and Nutrition Service, Hospital de la Santa Creu i Sant Pau, Sant Antoni Maria Claret, 167, 08025 Barcelona, Spain 2 General Surgery Service, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain 3 Biomedical Research Institute IIB Sant Pau, Barcelona, Spain 4 Universitat Autònoma de Barcelona, Sant Antoni Maria Claret, 167, 08025 Barcelona, Spain 5 Diabetes and Metabolic Diseases CIBER (CIBERDEM), Sant Antoni Maria Claret, 167, 08025 Barcelona, Spain Obesity Surgery https://doi.org/10.1007/s11695-020-04385-8