ABSTRACT
Objective:To investigate the correlation between serum cystatin C (CysC) and clinical and pathological features of IgA nephropathy.Methods:Four hundred and twenty-one cases of primary IgA nephropathy diagnosed by renal biopsy in Longhua Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from January 2010 to January 2021 were retrospectively analyzed. According to the serum CysC level at the time of renal biopsy, the patients were divided into high serum CysC group and normal serum CysC group, and the clinical data and pathological indices of the patients were compared. Spearman correlation analysis was used to analyze the correlation between estimated glomerular filtration rate (eGFR) and serum CysC. The clinicopathological factors related to the serum CysC level were analyzed by multiple linear regression. The area under the receiver operator characteristic curve (AUC) was used to evaluate the ability of serum CysC level to predict related pathological injury.Results:The age, prevalence of hypertension, serum creatinine, urea and uric acid levels of high serum CysC group were significantly higher than those of normal serum CysC group, while the eGFR level was significantly lower than that of normal serum CysC group ( P<0.05). Spearman correlation analysis showed that serum CysC was negatively correlated with eGFR ( r=-0.744, P<0.001). In terms of pathological injury, the degree of renal tubular atrophy and renal interstitial fibrosis (T) and renal arteriole wall thickening (A) in high serum CysC group were more serious than those in normal serum CysC group ( P<0.05). Multiple linear regression analysis showed that the prevalence of hypertension, serum creatinine, urea, uric acid, T and A were correlated with serum CysC levels (standard regression coefficient β=0.048, 0.299, 0.260, 0.134, 0.195, 0.068, respectively, P<0.05). After adding serum CysC on the basis of clinical features, the prediction efficiency of renal tubular atrophy and renal interstitial fibrosis was higher (AUC were 0.829 [95% CI 0.787-0.870], 0.847 [95% CI 0.808-0.886], P<0.05). Conclusions:Patients with older age, hypertension, poor renal function and severe pathological damage are more likely to have elevated serum CysC levels. Serum CysC was related to the prevalence of hypertension, creatinine, urea, uric acid, T and A. Combined with serum CysC level can effectively improve the ability prediction of T.