Glycemic variability and hypoglycemia before and after Roux-en-Y Gastric Bypass and Sleeve Gastrectomy - A cohort study of females without diabetes.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) lead to lower fasting glucose concentrations, but might cause higher glycemic variability (GV) and increased risk of hypoglycemia. However, it has been sparsely studied in patients without preoperative diabetes under normal living conditions. OBJECTIVES: To study 24-hour interstitial glucose (IG) concentrations, GV, the occurrence of hypoglycemia and dietary intake before and after laparoscopic RYGB and SG in females without diabetes. SETTING: Outpatient bariatric units at a community and a university hospital. METHODS: Continuous glucose monitoring and open-ended food recording over 4 days in 4 study periods: at baseline, during the preoperative low-energy diet (LED) regimen, and at 6 and 12 months postoperatively. RESULTS: Of 47 patients included at baseline, 83%, 81%, and 79% completed the remaining 3 study periods. The mean 24-hour IG concentration was similar during the preoperative LED regimen and after surgery and significantly lower compared to baseline in both surgical groups. GV was significantly increased 6 and 12 months after surgery compared to baseline. The self-reported carbohydrate intake was positively associated with GV after surgery. IG concentrations below 3.9 mmol/L were observed in 14/25 (56%) of RYGB- and 9/12 (75%) of SG-treated patients 12 months after surgery. About 70% of patients with low IG concentrations also reported hypoglycemic symptoms. CONCLUSIONS: The lower IG concentration in combination with the higher GV after surgery, might create a lower margin to hypoglycemia. This could help explain the increased occurrence of hypoglycemic episodes after RYGB and SG.

Circulating magnesium status is associated with type 2 diabetes remission after Roux-en-Y gastric bypass surgery: a long-term cohort study.

BACKGROUND: Low serum magnesium levels predict cardiovascular and all-cause mortality in patients with typ 2 diabetes. SETTING: Outpatient clinic of obesity and central hospital. OBJECTIVES: To assess long-term alterations in circulating magnesium status after Roux-en-Y gastric bypass (RYGB) surgery and associations with remission of type 2 diabetes (T2D). METHODS: Retrospective analysis of 5-year outcomes of plasma magnesium (p-Mg) and glucometabolic statuses in patients who underwent primary RYGB and who completed the annual follow-up program. Data were investigated from 84 patients without diabetes and 62 with T2D before RYGB, who showed either prolonged remission (n = 30), temporary remission (n = 16), or no remission (n = 16) after surgery. RESULTS: Body mass indexes before RYGB were similar in patients with and without T2D, irrespective of remission. The patients not achieving remission showed longer diabetes durations; higher circulating glucose levels; more intensive antidiabetic drug treatment, including insulin; and significantly lower p-Mg concentrations (.73 [±.08] mmol/L compared with .80-.82 [±.07] mmol/L, respectively; P < .01) than the groups showing remission or without diabetes before surgery. After RYGB, the p-Mg increased similarly, by 10-12% in the groups with T2D before surgery, irrespective of remission; however, the nonremission group did not reach the p-Mg levels registered in the other groups after follow-up. The nonremission group reached .82 (.09) mmol/L, compared with .87 (.06) and .88 (.08) mmol/L (P < .05), respectively, in patients with remission or without a history of diabetes. CONCLUSION: The p-Mg concentrations increased after RYGB, with similar increments irrespective of T2D remission; however, the nonremission group started from an inferior level and did not reach the p-Mg concentrations seen in the groups achieving remission or without a history of diabetes before surgery.

Comparison of Meal Pattern and Postprandial Glucose Response in Duodenal Switch and Gastric Bypass Patients.

BACKGROUND: Bariatric surgery improves glucose homeostasis; however, side effects such as hypoglycemia can occur. We investigated the effects of meals on interstitial glucose (IG) response in biliopancreatic diversion with duodenal switch (BPD-DS) and Roux-en-Y gastric bypass (RYGBP)-operated patients at least 1 year after surgery. METHODS: Thirty patients treated with BPD-DS or RYGBP were recruited at the outpatient Obesity Unit, Uppsala University Hospital. IG was measured by continuous glucose monitoring (CGM) for 3 consecutive days, and postprandial IG levels from 5 to 120 min were analyzed for 2 of these days. All intake of food and beverages was simultaneously registered in a food diary, which was processed using The Meal Pattern Questionnaire. RESULTS: Postprandial IG levels were significantly lower in BPD-DS (n = 14) compared to RYGBP (n = 15)-treated patients, with mean concentrations of 5.0 (± 1.0) and 6.3 (± 1.8) mmol/L respectively (p < 0.001). The mean postprandial IG increment was lower in BPD-DS than in RYGBP patients, 0.2 (± 0.6) vs. 0.4 (± 1.4) mmol/L (p < 0.001). Furthermore, the postprandial IG variability was less pronounced in BPD-DS than in RYGBP patients. The mean number of daily meals did not differ between the two groups, 7.8 (± 2.6) in BPD-DS and 7.2 (± 1.7) in the RYGBP (p = 0.56). CONCLUSION: BPD-DS patients demonstrated lower postprandial IG concentrations, with smaller postprandial IG increments and less pronounced postprandial IG variability compared to RYGBP patients. The two groups had similar meal pattern and the postprandial IG responses is probably associated with differences in postoperative physiology.

Increased circulating magnesium concentrations after Roux-en-Y gastric bypass surgery in patients with type 2 diabetes.

BACKGROUND: Low circulating magnesium concentrations predict cardiovascular and all-cause mortality in patients with type 2 diabetes (T2D). Epidemiologic and clinical studies have indicated lower extra- and intracellular magnesium concentrations in patients with diabetes. OBJECTIVE: We aimed to describe alterations, if any, in circulating magnesium concentrations after laparoscopic Roux-en-Y gastric bypass surgery (LRYGB) in patients with obesity and T2D. SETTING: Outpatient clinic of obesity and central hospital. METHODS: Retrospective analysis of 1-year outcome of plasma magnesium (p-Mg) and glucometabolic status in all consecutive patients who underwent primary LRYGBP and who completed the follow-up visits, including biochemical test panels 6 and 12 months after surgery. RESULTS: LRYGBP and complete follow-up visits were performed in 51 patients with T2D and 86 patients without T2D. All patients were given similar dietary advice and multivitamin and mineral supplementation after surgery. Before RYGB, the patients with T2D showed lower p-Mg compared with patients without T2D (.79 ± .06 mM and .82 ± .05 mM, respectively, P<.01). P-Mg was inversely correlated to fasting blood glucose and glycosylated hemoglobin levels. After surgery, mean p-Mg increased by 5.2% in the group with T2D compared with 1.4% in the patients without T2D (P<.01), ending at an equal level of .83 mM. The alterations in p-Mg were inversely related to the changes in fasting glucose and glycosylated hemoglobin concentrations. CONCLUSION: The lowered p-Mg associated with impaired glucometabolic status in patients with T2D was increased after LRYGBP, reaching similar concentrations as in patients without T2D.