Early diagnostic value of urinary insulin-like growth factor binding protein-7 in patients with sepsis-induced acute kidney injury

Abstract

Objective To evaluate the early diagnostic value of urinary insulin-like growth factor binding protein-7 (IGFBP-7) in sepsis-induced acute kidney injury (AKI), and to compare the effects of urinary IGFBP-7 to that of serum cystatin-C (sCys-C) and serum creatinine (sCr) on predicting the severity of sepsis-induced AKI patients. Methods A total of 105 patients with sepsis admitted to ICU in Tianjin First Hospital from September 2015 to August 2016 were divided into AKI group (n=48) and non-AKI group (n=57) according to the AKI diagnostic criteria. The samples of blood and urine of the patients were collected at 0, 3, 6, 12, 24 and 48 h, to measure the levels of urinary IGFBP-7, and serum Cys-C and sCr. Based on the receiver operating characteristic curve (ROC) and the area under the curve (AUC), the early diagnostic value of urinary IGFBP-7, and serum sCys-C and sCr in sepsis-induced AKI patients was determined. Results With the increase in length of ICU stay, the levels of urinary IGFBP-7, and serum sCys-C and sCr in AKI patients increased gradually. There was a significant difference between the two groups in the level of IGFBP-7 at 3 h[2.34(2.03, 4.19) ng/mL vs.1.79(1.51, 2.62) ng/mL, P<0.05]. At 6 h, the difference in sCys-C between two groups was statistically significant [(1.63±0.42) ng/mL vs.(1.20±0.46) ng/mL, P<0.05]. At 12 h, the difference in sCr between two groups was statistically significant [80.5(74.3, 88.0) ng/mL vs.77.0(67.0, 84.0) ng/mL, P<0.05]. The AUCs of urinary IGFBP-7 and sCys-C of sepsis-induced AKI patients were 0.881(95%CI: 0.813-0.949) and 0.782(95%CI: 0.692-0.872), which were superior to those in AUC of sCr 0.629(95%CI: 0.522-0.737). When the cutoff value of urinary IGFBP-7 was 1.82 ng/mL, the sensitivity was 93.8% and the specificity was 77.2%. Conclusions Urine IGFBP-7 and sCys-C have higher predictive value in sepsis-induced AKI than sCr, whereas urine IGFBP-7 is more sensitive and specific than sCys-C, suggesting that IGFBP-7 may be used as sepsis signs of early diagnosis of AKI. Key words: Urinary insulin-like growth factor binding protein-7; Acute kidney injury; Sepsis; Serum cystatin-C; Serum creatinine