Effects of SGLT2 inhibitors on renal function and serum electrolytes in diabetic chronic kidney disease patients

Objective: We aimed to investigate the effects of SGLT2 inhibitors on blood test parameters in patients with diabetic nephropathy (Stage 3–4 CKD) who were prescribed SGLT2 inhibitors in the outpatient and inpatient clinics of the Department of Internal Medicine at Dicle University. Methods: Patients diagnosed with Type 2 Diabetes Mellitus and Stage 3–4 Chronic Kidney Disease (GFR 20–60 mL/min/1.73 m²), who had laboratory data between January 1, 2017, and March 31, 2025, in Dicle University Faculty of Medicine Internal Medicine Outpatient and Inpatient Clinics, were retrospectively analyzed. Patients who were started on SGLT2 inhibitors formed the study group, and their lab parameters at baseline, 6 months, and 12 months were compared with those of the control group (patients not using SGLT2 inhibitors) at the same time intervals. Data were collected retrospectively from the hospital information management system. The study included 71 patients in the treatment group and 71 patients in the control group. Complete blood count, biochemistry, CRP, procalcitonin, HbA1c, C-peptide, ferritin, folate, vitamin B12, total iron, spot urine protein and creatinine, and blood gas parameters were evaluated at 0, 6, and 12 months. Results: When examining the demographic characteristics of the patient and control groups included in the study, the mean ages of both groups were found to be similar. The mean age of the patient group was 62.14 ± 10.41 years, while the control group had a mean age of 63.69 ± 13.84 years. Regarding gender distribution, 31% of the patient group were male and 69% were female; in the control group, 46.5% were male and 53.5% were female. The laboratory parameters of the patient group using SGLT-2 inhibitors and the control group were compared at the 0th, 6th, and 12th months. In the patient group, there was a statistically significant increase in e-GFR levels (p<0.001) and a significant decrease in creatinine levels (p<0.001) over time. In contrast, the control group showed a significant decrease in e-GFR (p<0.001) and a significant increase in creatinine levels (p<0.05). Serum uric acid levels significantly decreased in the patient group at 12 months (p<0.001), while no significant change was observed in the control group. ix In terms of electrolytes, the patient group showed a significant increase in magnesium levels over time (p<0.001) and a significant decrease in potassium and chloride levels (p<0.001 and p<0.05, respectively). No significant changes were observed in phosphorus and sodium levels. Calcium levels significantly increased at the 6th month and then declined at the 12th month in the patient group (p<0.05). In the evaluation of the lipid profile, the patient group showed significant decreases in LDL, total cholesterol, and triglyceride levels by the 12th month (p<0.001), while HDL levels increased significantly (p<0.05). In terms of glycemic control, significant improvements were observed in HbA1c and fasting glucose levels in the patient group (p<0.001). Additionally, hemoglobin and hematocrit levels were found to be higher in the patient group at the 6th and 12th months compared to the control group. Conclusion: Our study demonstrated that SGLT-2 inhibitors improve kidney function (increase in eGFR, reduction in proteinuria), enhance glycemic control (decrease in HbA1c), and induce significant positive changes in biochemical parameters in patients with diabetic chronic kidney disease. Our findings are consistent with large-scale studies in the literature, supporting the notion that SGLT-2 inhibitors not only provide glycemic control in diabetic patients but also exert a renoprotective effect in diabetic nephropathy. Keywords: Diabetes mellitus, Type 2 diabetes, SGLT2 inhibitors, Dapagliflozin, Empagliflozin, Canagliflozin, CKD, Diabetic nephropathy, Blood tests, Proteinuria, HbA1c, Urea, Creatinine, eGFR.