Clinical evaluation of assisted diagnosis of early diabetic kidney disease by serum C1q, NGAL and CysC

Objective To investigate the diagnostic value of serum complement component 1 q (C1q), cystatin C (CysC), neutrophil gelatinase-associated lipocalin (NGAL), creatinine (SCr) and urea (SUr) for early diabetic kidney disease. Methods A retrospective study was conducted in 530 subjects who visited or received physical examination in Mianyang Central Hospital from March 2017 to November 2017. Of these, 229 patients with diabetes mellitus (DM group) were divided into simple diabetes mellitus group (SDM group, n=100) and early diabetic kidney disease group (EDKD group, n=129) respectively, and 301 subjects were selected as the healthy control (HC group). The levels of serum C1q, CysC, NGAL, SCr and SUr were detected in all subjects. Then, the diagnostic values of single and combined detection of these indexes for early diabetic kidney disease were evaluated. The statistical difference among the observed indexes of each group were compared by one-way ANOVA, and the diagnostic performance of those indexes were evaluated by receiver operating characteristic curve(ROC) analysis. Results The median of serum C1q, CysC, NGAL and SCr in early diabetic kidney disease group were 187.80 mg/L, 1.02 mg/L, 148.70 μg/L and 72.00 μmol/L. The simple diabetes mellitus group were 177.00 mg/L, 0.80 mg/L, 116.20 μg/L and 55.35 μmol/L. The healthy control group were 163.60 mg/L, 0.75 mg/L, 104.20 μg/L and 59.40 μmol/L. Compared with simple diabetes group (t1 values were 6.50, 9.44, 3.87, 9.19 and 4.34, P 0.05) or NGAL+ SCr (z=1.806, P>0.05) did not further improve the diagnosis performance of early diabetic kidney disease . Conclusions C1q, CysC and NGAL with equal diagnostic performances are superior to SCr and SUr in diagnosis of early diabetic kidney disease. Among them, the combined detection of C1q and CysC has better diagnostic performance for early diabetic kidney disease.(Chin J Lab Med, 2018, 41: 847-852) Key words: Early diabetic kidney disease; Complement component 1q; Cystatin C; Neutrophil gelatinase-associated lipocalin; Creatinine