The value of cystatin C in early diagnosis of acute kidney injury and predicting prognosis after radical nephrectomy / 中华泌尿外科杂志

ABSTRACT

Objective:To investigate the value of cystatin C (Cys-C) in the early diagnosis of acute kidney injury (AKI) after radical nephrectomy and the predictive value for the prognosis of Cys-C based estimated glomerular filtration rate (eGFR Cys-C) after surgery. Methods:The clinical data of 118 patients who underwent unilateral radical nephrectomy in our hospital from January 2019 to December 2020 were retrospectively analyzed. According to the diagnostic criteria of AKI, they were divided into AKI group of 75 cases and no-AKI group of 43 cases. AKI group was (62.7±10.7) years old, with 49 males and 26 females. The no-AKI group was (62.3±12.8) years old, with 21 males and 22 females. The urea nitrogen was (4.9±1.3) mmol/L, creatinine (75.7±14.5)μmol/L, Cys-C (0.85±0.22) mg/L, eGFR Cr(76.3±11.2)ml/(min·1.73m 2), and eGFR Cys-C(101.4±17.4)ml/(min·1.73m 2)in AKI group before operation.In no-AKI group, preoperative urea nitrogen was (4.9±1.5) mmol/L, creatinine (74.5±13.1)μmol/L, Cys-C (0.81±0.29) mg/L, eGFR Cr(78.6±12.5)ml/(min·1.73m 2), and eGFR Cys-C(99.3±18.8)ml/(min·1.73m 2), and there were no significant differences in the values of urea nitrogen, creatinine, Cys-C and eGFR between the two groups before surgery ( P>0.05). ROC curve was used to analyze the diagnostic value of urea nitrogen, creatinine, Cys-C, eGFR calculated based on creatinine and Cys-C at 48h after surgery, and binary Logistic regression was used to analyze the risk factors for AKI. The creatinine status of patients diagnosed with SPS was evaluated 6 months after surgery, based on the definition of Cys-C based eGFR being less than 70% of creatinine-based eGFR(SPS=eGFR Cys-C/ eGFR Cr≤0.7). Results:In AKI group, creatinine was(115.2±22.1)μumol/L, Cys-C (1.8±0.27) mg/L, eGFR Cr (51.6±9.6)ml/(min·1.73m 2), and eGFR Cys-C(43.4±8.5)ml/(min·1.73m 2)48 h after operation. The creatinine was(92.7±13.3)μmol/L, Cys-C(1.3±0.23) mg/L, eGFR Cr(62.2±11.3)ml/(min·1.73m 2), and eGFR Cys-C(61.5±9.5)ml/(min·1.73m 2) in no-AKI group, and difference were statistically significant between the two groups ( P<0.01). ROC curve was used to analyze the diagnosis of AKI. Creatinine, Cys-C, eGFR Cr and eGFR Cys-Cwere all of diagnostic value for AKI (all P<0.01), and AUC(Area under curve) were 0.809, 0.889, 0.761 and 0.925 respectively. The sensitivity, specificity and area under the curve of eGFR Cys-C were 93.3%, 74.4% and 92.5% respectively. Binary Logistic regression analysis showed that creatinine( OR=10.851, 95% CI 2.322-50.688, P=0.004), Cys-C( OR=10.016, 95% CI 2.306-43.362, P=0.001), eGFR Cr( OR=17.923, 95%CI 3.216-53.172, P=0.001) and eGFR Cys-C( OR=19.817, 95% CI 3.367-55.263, P=0.001)were all independent risk factors for AKI. The predictive accuracy of eGFR Cys-C, creatinine, Cys-C, eGFR Cr were 91.6%, 85.7%, 90.2%, 88.5%, respectively. There were 15 cases were confirmed SPS in the AKI group, and only 2 cases were confirmed SPS in the no-AKI group, indicating patients in the AKI group developed more SPS than those in the no-AKI group, with statistically significant difference(Kappa value was 5.22, P=0.02). The 6-month follow-up showed that the creatinine of confirmed SPS was (103.8±23.4)μmol/L and the creatinine of unconfirmed SPS was (86.8±27.2)μmol/L, with statistically significant difference ( P<0.01). Conclusions:eGFR Cys-C calculated based on Cys-C has high sensitivity in diagnosing AKI and has early diagnostic value. Patients diagnosed with SPS based on eGFR Cys-C had higher creatinine 6 months after surgery.