ObjectiveTo explore the clinical value of serum kidney injury molecule-1(KIM-1) in the prediction of lupus nephritis(LN) in patients with systemic lupus erythematosus(SLE).

MethodsA total of 78 SLE patients were selected.The median follow-up time was 5.9 years(1-9.5 years).Enzyme-linked immunosorbent assay was used to detect the levels of serum KIM-1 at baseline.ROC curve was drawn to analyze the value of KIM-1 in predicting LN, calculate AUC, 95% confidence interval(CI), sensitivity and specificity under ROC curve.Kaplan-Meier method was used to draw survival curve of SLE patients with different KIM-1 expression levels, and compare with log-Rank test; Cox regression analysis was used to determine the factors of LN.

ResultsDuring the follow-up period, LN occurred in 38 patients(48.72%).The serum KIM-1 concentration in LN group was(46.02±6.28) ng/L, which was significantly higher than that in non-LN group(23.56±5.29) ng/L(P < 0.01).With 42.35 ng/L as the cutoff value, KIM-1 had a better effect on predicting LN in SLE patients(AUC: 0.715, 95%CI: 0.589-0.841;sensitivity and specificity 82.01% and 56.33%, respectively).LN occurred in 37 cases(71.15%) in high KIM-1 group.LN occurred in 8 cases(30.77%) in low KIM-1 group.The median time from SLE diagnosis to LN in high KIM-1 group was 6.7 years(4.8-8.5 years), significantly shorter than that in low KIM-1 groupmedian time was 8.8 years(7.7-9.7 years)(P < 0.05).KIM-1 is an independent influencing factor of LN(HR=2.301, 95%CI: 1.235-3.964, P < 0.01).

ConclusionsThe level of serum KIM-1 was significantly increased in patients with SLE complicated with LN, which may be an effective biomarker for the prediction of LN.