Correlation of Indoleamine-2,3-Dioxygenase and Chronic Kidney Disease: A Pilot Study

OBJECTIVE: To explore the correlation of indoleamine-2,3-dioxygenase (IDO) and chronic kidney disease (CKD). METHODS: A total of 154 CKD patients and 42 non-CKD patients were recruited. Patients were grouped into ACR1~ACR3 (<30 mg/g, 30-300 mg/g, and >300 mg/g). Biomarkers in different groups were compared by ANOVA. Correlation was calculated by Pearson or Spearman analysis and binary logistic regression. The ROC curve was also performed. RESULTS: The levels of albumin, serum creatinine (sCr), and IDO in non-CKD patients were significantly different from those in CKD3-CKD5 stages (p < 0.05). IDO was correlated with age, proteinuria, ACR, and eGFR (p < 0.01). After adjusting for CKD-related indices, ln(IDO) was an independent risk factor for CKD (3.48, p < 0.05). The analysis of ROC curve revealed a best cut­off for IDO was 0.0466 and yielded a sensitivity of 83.8% and a specificity of 75%. Hemoglobin, total protein, and albumin in the ACR1 group were significantly higher than those in the ACR2 and ACR3 groups (p < 0.01), while sCr and IDO levels were significantly lower than those in the ACR2 and ACR3 groups (p < 0.01 or p < 0.05). After adjusting for CKD-related indices, ln(IDO) was still an independent risk factor for ACR (OR = 2.7, p < 0.05). The analysis of ROC curve revealed a best cut­off for IDO was 0.075 and yielded a sensitivity of 71.9% and a specificity of 72.2%. CONCLUSION: IDO may be a promising biomarker to predict CKD and assess kidney function.