Comparison of renal function of the patients receiving linagliptin or vildagliptin in uncontrolled type 2 diabetes mellitus: An observational study in the backdrop of the COVID-19 pandemic.

Background: Dipeptidyl peptidase 4 (DPP-4) inhibitors are primarily excreted renally. Linagliptin is an exception with excretion primarily through enterohepatic system and is expected to have a better renal profile, though real-world data are scarce. Comparative studies on the renal safety and glycaemic control with linagliptin versus popular DPP-4 inhibitors such as vildagliptin are crucial, especially in the background of COVID-19 pandemic that hugely impacted glycemic control in India's large type 2 diabetes mellitus (T2DM) population.

Materials and methods: Adult T2DM patients not controlled with metformin alone, added linagliptin (5 mg once daily) or vildagliptin (50 mg twice daily) in the tertiary care outpatient department setting were included in the study. Parameters such as glycosylated hemoglobin, fasting blood glucose, postprandial blood glucose, blood urea nitrogen, serum creatinine, estimated glomerular filtration rate (eGFR), change in renal function, glycemic control, and clinical parameters were compared at baseline, 2 months, and 6 months of treatment. All adverse events were analyzed using the WHO-UMC scale.

Results: Both groups achieved similar glycemic control, however, accompanied with impairment of renal parameters after 6 months. Compared to linagliptin, almost 300% rise in creatinine and 140% fall in eGFR were noted in the vildagliptin recipients. However, the difference in serum creatinine or eGFR could not attain statistical significance in the study.

Conclusion: Both linagliptin and vildagliptin can help to achieve glycemic control despite possible influence of the COVID-19 pandemic and are generally well tolerated. However, renal functions are better preserved with linagliptin. Further studies involving a larger sample size and longer follow-up are recommended before generalization of the findings of the present study.