Enlarged Kidney Parenchymal Volume Predicts Poor Kidney Outcomes in Advanced Stage Diabetic Nephropathy

Background: Early diabetic nephropathy (DN) is characterized by enlarged kidneys, but its clinical significance in advanced stages is not well understood. This study aimed to determine whether total kidney parenchymal volume (VTKP) is associated with renal outcomes in advanced stage DN patients with overt proteinuria. Methods: VTKP was estimated in biopsy-proven DN patients using unenhanced computed tomography imaging. Clinicopathological findings, kidney morphometric parameters and renal outcomes were compared among tertile groups based on VTKP. The end point was defined as a 50% reduction in eGFR or ESKD. Results: A total 81 patients were included in this study (84% male, median 55 years, eGFR 38 [24-52] ml/min/1.73m2,urinary protein 4.4 [2.2-7.0] g/day and median 1.8-year follow-up). Median values of VTKP were 111 [98-121], 156 [149-164], and 214 [191-243] cm3/kidney in the low, intermediate, and high VTKP groups. There were no differences in sex, hypertension, HbA1c and BMI among groups. Age showed a decreasing trend, while eGFR and proteinuria showed an increasing trend with VTKP. In the log-rank trend test, greater VTKP was significantly associated with poor renal outcomes (Figure). Interestingly, the associations between VTKP and renal outcomes were independent of age, eGFR and proteinuria levels at presentation (Table). Conclusion: In patients with advanced stage DN, greater VTKP at presentation is associated with poor renal outcomes, independent of kidney function and proteinuria levels.eGFR ≥50% decline or ESKD Cox proportional hazard model - Variable Hazard ratio 95% confidence interval P value Age, per year 1.01 0.99-1.04 0.2 Urinary protein, per g/day 1.10 1.04-1.16 <0.001 eGFR, per mL/min/1.73m2 0.97 0.95-0.98 0.001 VTKP, per 10cm3 1.09 1.01-1.18 0.001