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 (ΔAGT) were calculated by subtracting urinary AGT/creatinine (Cr) at baseline from urinary AGT/Cr after 1 year. ΔAGT was significantly inversely correlated with annual eGFR change (β = −0.29, P = 0.006; β = −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 ΔAGT 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 μg/g Cr, P = 0.081). The ΔAGT values remained significantly correlated with the annual rate of eGFR change (β = −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. ΔAGT is inversely correlated with annual changes in eGFR in type 2 diabetes patients with preserved kidney function, particularly in RAS blocker-naïve patients.