Correlation of Magnesium Levels and Retinopathy in Patients with Type 2 Diabetes Mellitus

Abstract Background Diabetes mellitus is a set of metabolic diseases characterized by chronic hyperglycemia as a consequence of lack in insulin action, secretion, or both. All of which lead to long-term damage and dysfunction of different organs predominantly the eyes, kidneys, nerves, heart, and blood vessels. Diabetic retinopathy (DR) is a chronic inflammatory neurovascular complication linked to DM, and it is known to be the leading cause of preventable blindness, affecting more than 415 million people worldwide. Recent studies showed that Magnesium deficiency has been correlated to type 2 diabetes mellitus and diabetic retinopathy (DR). Objective To investigate the correlation of magnesium levels and retinopathy in patients with type 2 diabetes mellitus and magnesium status in type 2 diabetes mellitus in comparison to healthy population. Methods The study was a case-control study conducted on 180 cases attending diabetes outpatient clinic at Ain Shams university hospital: 38 males, 62 females divided into 3 groups, Group Ι: 60 type 2 diabetic patient without diabetic retinopathy, Group ΙΙ: 60 type 2 diabetic patients with diabetic retinopathy & Group ΙΙΙ: 60 cases as a control group of non-diabetic patients. Results In our study results, serum magnesium (Mg) levels remarkably lower in type 2 diabetes patients (groups Ι & ΙΙ) compared to controls (group ΙΙΙ). On comparing groups I & II serum Mg levels were significantly lower in group II (type 2 diabetes patients with diabetic retinopathy) compared to group I (type 2 diabetes patients without diabetic retinopathy). This study showed that serum Mg levels had a (PPV) Positive predictive value for diabetic retinopathy 80 % when their levels are ≤ 1.5 mg/dl, with sensitivity 46.67% and specificity 88.33% (this means that serum Mg levels can predict diabetic retinopathy among patients with type 2 diabetes mellitus when their levels are below or equal 1.5 mg/dl). In a multivariate analysis magnesium is considered an independent risk factor for diabetic retinopathy in type 2 diabetes mellitus after adjustment of Age, SBP, cholesterol and eGFR. Conclusion Magnesium level is lower among patients with type 2 diabetes compared to normal population. Magnesium is considered an independent risk factor for diabetic retinopathy in type 2 diabetes mellitus. Magnesium level ≤ 1.5 mg/dl has a PPV for DR with sensitivity 46.67% and specificity 88.33%.