Table 3: Multiple stepwise regression and principal component regression of Ln(ACR) and related factors.

Standard errorStandard regression coefficient

Constant1.9140.4294.466<0.001
Principal Component 1.0380.0520.59220.031<0.001
UA0.0040.0010.1646.210<0.001
BUN0.2070.0450.1254.552<0.001
Duration0.0270.0080.0913.572<0.001
eGFR−0.0080.004−0.139−5.356<0.001
TG0.1140.0320.0943.603<0.001
25(OH)VD3−0.0170.007−0.058−2.292=0.022
LDL0.1130.0500.0572.240=0.025

Since the values of HIF-1α, VEGF, vWF, and IGF-1 were correlated, their unique principal component was substituted for them in the model and the principal component = 0.803 HIF-1α + 0.864 VEGF + 0.929 IGF-1 + 0.725 vWf (HIF-1α: hypoxia-inducible factor-1α; VEGF: vascular endothelial growth factor; IGF-1: insulin-like growth factor-1; vWf: von Willebrand factor). In the formula, each variable was no longer the original variable but standardized variable and the coefficients before the standardized variables represented the correlation coefficients of principal component and the corresponding original variables. Since only one principal component was extracted among the four serum factors and the correlation coefficients were all close to 1, it showed that the four factors were highly correlated and the component could almost contain all the information of the four variables.
UA: uric acid; BUN: blood urea nitrogen; eGFR: estimated glomerular filtration rate; TG: triglyceride; 25(OH)VD3: 25-hydroxy vitamin D3; LDL: low-density lipoprotein.