Higher magnesium levels are associated with better glycaemic control and diabetes remission post-bariatric surgery

Abstract Background Low Magnesium (Mg) dietary intake has been associated with increased risk of type 2 diabetes mellitus (T2DM). Furthermore, in patients with T2DM, hypomagnesemia is associated with worst glycaemic control. Bariatric surgery (BS) remains the most effective treatment in severe obesity and also provides resolution/improvement of T2DM. Our aim is to evaluate the association between Mg supplementation post-BS and Mg serum levels with diabetes status after BS. Methods We performed an observational study on patients with obesity and T2DM who underwent BS. Data was assessed preoperatively and one-year after surgery. Results We included a total of 403 patients with T2DM. At baseline, 43.4% of the patients had Mg deficiency. Pre-operatively, patients with Mg deficiency had poorer glycaemic control – HbA1c 7.2 ± 1.6% vs 6.4 ± 1.0% (p < 0.001), fasting plasma glucose 146.2 ± 58.8mg/dL vs 117.5 ± 36.6 mg/dL (p < 0.01) and were under a greater number of anti-diabetic drugs 1.20 ± 0.99 vs 0.82 ± 0.82 (p = 0.001). These findings persisted post-operatively. Post-operatively, patients that were under Mg supplementation had similar serum Mg values but better HbA1c – HbA1c 5.5 ± 0.5% vs 5.7 ± 0.9 (p = 0.007). At the first year post-surgery, 58.4% of the patients had total remission of T2DM and 4.1% had partial remission. Patients without Mg deficiency at 1-year post-surgery had higher rates of total and partial remission. Higher serum Mg levels at baseline is an independent predictor of T2DM remission (p < 0.0001). Conclusion Higher serum Mg levels in patients with T2DM submitted to BS are associated with better glycaemic control and higher rates of T2DM remission at the first year post-surgery.