Diabetic peripheral neuropathy as an independent predictor of renal function decline in type 2 diabetes: a propensity score-matched retrospective cohort study using DPN-Check®.

BACKGROUND

Diabetic peripheral neuropathy (DPN) is highly prevalent in type 2 diabetes, but its specific impact on long-term renal outcomes remains unclear. We aimed to determine whether DPN, objectively assessed using the DPN-Check® device, independently predicts accelerated renal function decline.

METHODS

This retrospective cohort study evaluated 323 Japanese patients with type 2 diabetes who underwent neuropathy assessment using DPN-Check® between 2015 and 2017. Propensity score matching for baseline covariates (including age, HbA1c, estimated glomerular filtration rate [eGFR], and albuminuria) yielded 174 well-matched patients (87 with DPN, 87 without DPN). The primary outcome was a composite of renal events (≥ 30% eGFR decline, renal replacement therapy, or renal or cardiovascular death) over a five-year follow-up. Secondary outcomes included annual eGFR slopes and sensitivity analyses stratified by baseline albuminuria categories.

RESULTS

Over five years, renal events occurred significantly more frequently in the DPN group (19 versus 6 events; log-rank P < 0.01). Multivariate Cox regression confirmed DPN as an independent predictor of renal events (adjusted hazard ratio 3.18, 95% CI 1.34 to 8.77, P < 0.01). The DPN group exhibited a steeper annual eGFR decline (-1.9 vs. -1.1 mL/min/1.73 m2/year, P < 0.01). Stratified analysis revealed that DPN significantly predicted renal events even in patients with normoalbuminuria.

CONCLUSIONS

DPN measured by DPN-Check® independently predicts subsequent renal deterioration in type 2 diabetes. Routine objective neuropathy screening can enhance renal risk stratification and guide clinical management.