After adjustment for the baseline age, sex, duration of diabetes, diabetic neuropathy, eGFR, serum C4, serum C3 and interstitial inflammation, glomerular C4c remained an independent risk factor for renal survival by multivariate Cox regression (HR 1.584, 95%CI [1.001, 2.508], p = 0.0497) in DKD patients. Here, C3 is linked to diabetic kidney disease.