REN and diabetic kidney disease: However, on comparing TP to the renin–angiotensin system (RAS) inhibitors in DKD treatment, there was no marked difference in ameliorating albuminuria (3 studies; SMD: –0.35 [–0.72, 0.02], I2 = 41%), serum creatinine (3 studies; SMD: –0.07 [–0.62, 0.48], I2 = 10%), and blood urea nitrogen (2 studies; SMD: –0.35 [–0.97, 0.28], I2 = 0%).