Changes in Urinary Angiotensinogen Associated with Deterioration of Kidney Function in Patients with Type 2 Diabetes Mellitus

Urinary angiotensinogen (AGT) is potentially a specific biomarker for the status of the intrarenal renin-angiotensin system (RAS) in patients with diabetes mellitus. We explored whether changes in urinary AGT excretion levels were associated with the deterioration of kidney function in type 2 diabetes patients with preserved kidney function. Urinary baseline AGT levels were measured in 118 type 2 diabetic patients who were not taking RAS blockers and who had estimated glomerular filtration rates (eGFRs) >= 60 mL/min/1.73 m(2). A total of 91 patients were followed-up for 52 months. Changes in urinary levels of AGT (Delta AGT) were calculated by subtracting urinary AGT/creatinine (Cr) at baseline from urinary AGT/Cr after 1 year. Delta AGT was significantly inversely correlated with annual eGFR change (beta= -0.29, P = 0.006; beta = -0.37, P = 0.001 after adjusting for clinical factors). RAS blockers were prescribed in 36.3% of patients (n = 33) during follow-up. The Delta AGT values were lower in the RAS blockers users than in the non-RAS blockers users, but the differences were not statistically significant (7.37 +/- 75.88 vs. 22.55 +/- 57.45 mu g/g Cr, P = 0.081). The Delta AGT values remained significantly correlated with the annual rate of eGFR change (beta = -0.41, P = 0.001) in the patients who did not use RAS blockers, but no such correlation was evident in the patients who did Delta AGT is inversely correlated with annual changes in eGFR in type 2 diabetes patients with preserved kidney function, particularly in RAS blocker-naive patients.