INS and diabetes mellitus: Logistic models showed that increasing FCP was a risk factor for DKD (OR 1.350, 95% CI 1.189-1.532; P < 0.05), and increasing C2/C0 was a protective factor for both DKD (OR 0.894, 95% CI 0.833-0.959; P < 0.05) and DR (OR 0.851, 95% CI 0.787-0.919; P < 0.05), even after adjusting for all potential confounders (age, sex, SBP, HbA1c, TC, TG, LDL, HDL, smoking history, education, duration of diabetes, ever insulin use, and BMI).