Plasma copeptin level in type 2 diabetic patients and its role in diabetic nephropathy

BackgroundCopeptin, the stable COOH-terminal portion of pre-provasopressin and a surrogate marker of vasopressin, was shown to be positively associated with the decline in kidney function in the general population. However, the impact of copeptin on renal function in diabetic patients remains unclear. This study aims to assess the clinical significance of plasma copeptin level in type 2 diabetic patients with and without nephropathy and to evaluate its relation to various clinical and laboratory parameters.MethodsThis study was carried out on 45 type 2 diabetic patients, divided according to urinary albumin/creatinine ratio into 15 with normoalbminuria, 15 with microalbminuria and 15 with macroalbminuria. Also, 15 healthy subjects were included as a control group. Plasma copeptin level, glycosylated hemoglobin percentage, urinary albumin/ creatinine ratio and serum creatinine were measured. Estimated glomerular filtration rate (eGFR) was calculated.ResultsThe mean plasma copeptin level was statistically significantly higher in patients with microalbuminuria as compared to the control and normoalbuminuric groups. It was also, higher in patients with macroalbuminuria as compared to the control, normoalbuminuric and microalbuminuric groups. Plasma copeptin level was positively correlated with glycosylated hemoglobin, urinary albumin /creatinine ratio and serum creatinine but negativey correlated with eGFR.ConclusionAn increased plasma copeptin level is considered as a good predictor for deterioration of renal function in diabetic patients, suggesting that copeptin can be used to identify diabetics at risk for diabetic kidney disease development. Clearly, further well-designed prospective studies are required to prove this hypothesis.