Intrarenal Resistive Index and Kidney Volume: Key Indicators of Early Diabetic Kidney Disease in Youth-Onset, Long-Duration Type 1 Diabetes

Abstract

Background: The aim of this study is to explore the potential of non-invasive, ultrasound-based markers—kidney volume (KV) and intrarenal resistive index (RI)—for predicting early onset ofdiabetic kidney disease (DKD). Additionally, we intend to assess the correlation between these ultrasound markers and specific serum inflammatory cytokines in patients with youth-onset and long-duration type 1 diabetes (T1D). Methods: A cross-sectional study was conducted from May 2020 to October 2021 on adolescents and young adults with T1D (50 males and 59 females) for over 10 years. The cohort was divided into Group 1 (N=96, normoalbuminuria: UACR < 30 mg/g) and Group 2 (N=13, hyperalbuminuria: UACR ≥30 mg/g). Renal and Doppler ultrasound examinations were performed by a senior pediatric nephrologist. We also analyzed eight proinflammatory cytokines/chemokines (e.g., sCD40L, Fractalkine, IL-1β, IL-6, IP-10, TNF-α, VEGF-A and RANTES) in serum. Patient demographic and clinical data were retrospectively collected. Results: We enrolled 109 diabetic patients with a median age of 24.4 years, a median T1D duration of 17.0 years, and a median age of onset at 7.7 years. T1D patients with hyperalbuminuria demonstrated significantly higher intrarenal RI and larger KV than those with normoalbuminuria (Mann-Whitney U test, P< 0.05). Serum concentrations of sCD40L and IL-1β showed a positive correlation with left KV. Moreover, increased serum IL-6 and VEGF-A concentrations were associated with a rise in the average RI in both kidneys Conclusions: Non-invasive ultrasound biomarkers, specifically intrarenal RI and KV, show their potential for improving early detection of preclinical DKD in the patients living with long-duration T1D.