Early detection of diabetic kidney disease (DKD) remains challenging in adolescents and young adults with type 1 diabetes mellitus (T1DM), as conventional albuminuria indices may miss early kidney injury and can regress over time. A prospective cohort study published in Pediatric Nephrology evaluated whether urinary podocyte- and tubule-derived biomarkers could identify subclinical kidney injury and predict long-term DKD risk before overt albuminuria develops.
The analysis included 109 participants with T1DM and 30 age-matched healthy controls. Baseline urinary podocalyxin-to-creatinine ratio (u-PCX/Cr), urinary nephrin-to-creatinine ratio (u-nephrin/Cr), and urinary liver-type fatty acid-binding protein-to-creatinine ratio (u-LFABP/Cr) were measured by enzyme-linked immunosorbent assay and indexed to creatinine. Albuminuria was assessed using 24-hour urinary albumin excretion rate (u-AER) and spot urinary albumin-to-creatinine ratio (u-ACR). Fifty-one participants underwent reassessment after 12 years.
Findings
- Normoalbuminuria was present in 90% of participants at baseline, yet urinary u-PCX/Cr, u-nephrin/Cr, and u-LFABP/Cr levels were higher in participants with T1DM than in healthy controls (all p≤0.001).
- Incident DKD developed in 7 of 51 participants during the 12-year follow-up period.
- Baseline u-PCX/Cr demonstrated strong discrimination for incident DKD (AUC, 0.96; 95% CI, 0.91-1.00).
- A baseline u-PCX/Cr threshold <78 ng/mgCr had a negative predictive value of 100%, while values ≥193 ng/mgCr demonstrated 95.5% specificity for incident DKD.
- Incident DKD occurred in 0% of participants with baseline u-PCX/Cr <78 ng/mgCr, 20% with values between 78–193 ng/mgCr, and 75% with values ≥193 ng/mgCr (p-trend<0.001).
- Baseline spot u-ACR also demonstrated good prognostic performance for incident DKD (AUC, 0.87; 95% CI, 0.74–1.00).
The findings suggest that urinary podocyte-derived biomarkers may provide complementary prognostic information for long-term DKD risk in adolescents and young adults with T1DM.
