Objective  To explore the predictive value of liver fibrosis index in contrast-induced nephropathy（CIN） of diabetics with normal renal function after percutaneous coronary angioplasty and interventional therapy（PCI）.

Methods  From January 2020 to June 2022, 155 diabetics of coronary heart disease（CHD） with normal renal function were selected as research subjects. There were 109 males（70.3%） and 46 females（29.7%） with an average age of （53.2 ± 6.5）（37-65） years. PCI was performed as needed. The occurrence of CIN within 72h post-PCI was recorded. According to the presence or absence of CIN, they were assigned into two groups of CIN and N-CIN. General profiles and liver fibrosis related parameters of two groups were compared. Multivariate logistic regression analysis was employed for evaluating the value of liver fibrosis index in predicting CIN of diabetics post-PCI. Receiver operating characteristic（ROC） curve of liver fibrosis index was plotted in predicting CIN of diabetics post-PCI and decision curve for predicting the net benefit of CIN.

Results  Univariate analysis indicated that erythrocyte distribution width（13.3 ± 1.6）% vs （10.1 ± 1.7）%, t = 2.667, P = 0.028, average platelet volume （12.9 ± 2.3） vs （10.2 ± 1.8） fL, t = 2.458, P = 0.034, C-reactive protein（CRP）（7.4 ± 1.4） mg/L vs （5.7 ± 1.2） mg/L, t = 2.896, P = 0.021, type Ⅳ collagen（C-IV）（65.5 ± 7.4） μg/L vs （52.3 ± 6.9） μg/L, t = 6.778, P＜0.001, hyaluronic acid（HA）（89.4 ± 7.7） μg/L vs （78.2 ± 7.2） μg/L, t = 4.332, P＜0.001 and laminin （LN）（93.3 ± 8.2） μg/L vs （81.2 ± 8.9） μg/L, t = 3.778, P＜0.001 were significintly higher in CIN group than those in N-CIN group. After adjusting for confounding factors, multivariable logistic regression analysis revealed that C-Ⅳ（OR = 2.717, 95%CI:1.237-4.347, P = 0.004）, HA（OR = 2.695, 95%CI:1.932-4.989,P = 0.008） and LN（OR = 2.588, 95%CI:1.654-4.935, P = 0.011） were independent predictors of diabetics post-PCI（P＜0.05）. ROC analysis showed that C-Ⅳ, HA and LN had some predictive values for CIN of diabetics post-PCI（P＜0.05）. The area under the curve（AUC） of C-Ⅳpredicting CIN of diabetics post-PCI was 0.932（0.887-0.966） with an optimal diagnostic cut-off point of 63.3 μg/L, AUC of HA 0.846（0.774-0.889） with an optimal diagnostic cut-off point of 85.4 μg/L and AUC of LN 0.812（0.745-0.857） with an optimal diagnostic cut-off point of 90.2 μg/L. The value of joint prediction of three indicators was the highest with AUC of 0.963（0.921-0.992）. The results of decision curve analysis indicated that within the most reasonable range of threshold probability, these three independent predictors had an excellent net benefit in predicting the occurrence of CIN and the net benefit of joint prediction was higher than that of a single indicator.

Conclusion  Preoperative levels of C-Ⅳ, HA and LN are independent predictors of CIN in diabetics post-PCI. And the combined prediction efficiency and net benefit of three indicators are higher than that of a single index.