Relationship between count of urinary red blood cells and clinical manifestations and prognoses of diabetic kidney disease

Objective To explore the correlation between count of urinary red blood cells （RBCs） in urinary RBC phase and severity and prognosis of diabetic kidney disease （DKD）.Methods Baseline urinary RBC phase，clinical parameters and renal pathological data were retrospectively reviewed for 144 DKD patients diagnosed by renal biopsy.The correlations were examined between total count of urinary RBCs，count of abnormal RBCs，rate of abnormal RBCs，various clinical parameters and pathological changes.Patients with end-stage renal disease or dying from renal causes within 1 year were defined as renal endpoint events.The differences in renal prognosis between patients with different levels of urinary RBC count were compared by Kaplan-Meier method and log-rank test.Univariate COX analysis was performed for identifying the risk factors of renal outcomes.And multivariate COX analysis was employed for determining independent risk factors related to renal outcomes.Results Total count of urinary RBCs and count of urinary malformed RBCs were correlated positively with 24 h urinary protein，glomerular classes and IFTA gradeand yet negatively with superoxide dismutase，hemoglobin and albumin.And 88 of them were followed up for 1 year.With count of urinary RBCs as receiver operating characteristic curve for end-point event occurring within 1 year，optimal diagnostic threshold value was 12 750/mL for judging the prognosis.According to total count of urinary RBCs，they were divided into three levels of no hematuria （<8000/mL），mild hematuria （8000-12 750/mL） and significant hematuria （≥12 750/mL）.Significant hematuria group had the worst prognosis.No prognostic difference existed between mild hematuria and nohematuria groups.Univariate COX analysis indicated that significant hematuria was a risk factor for poor renal prognosis.And higher levels of 24 h urinary protein and blood pressure also boosted the risks of poor renal outcome.Estimated glomerular filtration rate （eGFR），hemoglobin and albumin were the protective prognostic factors.Multivariate COX analysis revealed that significant hematuria，eGFR and diastolic blood pressure remained independent risk factors of renal outcomes for DKD patients within 1 year.Conclusion Totalcount of urinary RBCs in urinary RBC phase may be utilized as an effective and convenient marker for judging the severity of disease and the prognosis of DKD patients.