Predicting Renal Outcomes in Patients With DKD

Worldwide, the most common cause of end-stage kidney disease (ESKD) is diabetic kidney disease (DKD). Results of studies have suggested that urinary podocyte stress biomarker (podocin:nephrin mRNA ratio), is a surrogate marker of podocyte injury in patients with nondiabetic kidney disease. 

Researchers, led by Lingfeng Zeng, PhD, conducted a study of 118 patients with biopsy-proven DKD and 13 nondiabetic controls. Participants’ urinary mRNA levels of nephrin, podocin, and aquaporin-2 (AQP2) were quantified. The outcome of interest was a renal event at 12 months, defined as death, the need for dialysis, or a 40% reduction in glomerular filtration rate. 

In the group with DKD, urinary podocin:nephrin mRNA ratio was significantly higher than in the control group (P=.0019). There were no differences between the two groups in urinary nephrin:AQP2 or podicin:AQP2 mRNA ratios. 

In the DKD group, there was a correlation between urinary podocin:nephrin mRNA ratio and the severity of tubulointerstitial fibrosis (r=0.254; P=.006). Urinary podocin:nephrin mRNA ratio was also associated with renal event-free survival (EFS) at 12 months (unadjusted hazard ratio [HR], 1.523; 95% CI, 1.157-2.006; P=.003). Following adjustment for clinical and pathological factors, there was a trend for urinary podocin:nephrin mRNA ratio as a predictor of renal EFS; however, the result did not reach statistical significance (adjusted HR, 1.327; 95% CI, 0.980-1.797; P=.067). 

In conclusion, the authors said, “Urinary podocin:nephrin mRNA ratio has a marginal prognostic value in biopsy-proven DKD. Further validation is required for DKD patients without kidney biopsy.” 

Source: BMC Nephrology