# Associations of Skin Autofluorescence with Diabetic Kidney Disease in Type 2 Diabetes

## TL;DR

This study shows that skin autofluorescence is a better indicator of diabetic kidney disease than blood sugar levels in type 2 diabetes patients.

## Contribution

Demonstrates that skin autofluorescence is independently linked to kidney disease in type 2 diabetes, beyond traditional blood markers.

## Key findings

- Skin autofluorescence strongly correlates with diabetic kidney disease prevalence.
- Each unit increase in skin autofluorescence raises kidney disease risk by 1.6%.
- Skin autofluorescence is linearly associated with worsening kidney function markers.

## Abstract

Background: Diabetic kidney disease (DKD), a severe chronic complication of diabetes, significantly impacts the quality of life and life expectancy of affected individuals. Meanwhile, advanced glycation end products (AGEs) are believed to play a central role in the pathogenesis of DKD. Skin autofluorescence (SAF) is a well-validated, noninvasive technique for the estimation of AGE levels in the dermis. Aims: This study aims to evaluate the correlation between SAF and DKD prevalence, as well as the association between SAF and renal function parameters, in patients with Type 2 Diabetes Mellitus (T2DM). Methods: This cross-sectional analysis included 1259 hospitalized T2DM patients. SAF was measured using a spectroscopy device. Logistic regression analysis, p-trend analysis, and restricted cubic spline were performed with the prevalence of DKD as the dependent variable. Multiple linear regression analyses were conducted to investigate the associations of SAF with renal function parameters, specifically the estimated glomerular filtration rate (eGFR) and the log-transformed albumin-to-creatinine ratio (ln(ACR)). Results: The prevalence of DKD was strongly associated with SAF rather than with glycosylated hemoglobin (HbA1c). For each arbitrary unit (AU) increase in SAF, DKD incidence rose by 1.6%. A significant stepwise increase in the odds ratio (OR) of DKD was observed across SAF quartiles. A dose-response relationship existed between SAF and the OR value of DKD. Additionally, SAF showed a linear correlation with eGFR and ln(UACR). For each AU increase in SAF, eGFR decreased by 0.14 mL/min/1.73 m2, while UACR increased by 1.2%. Conclusions: Elevated SAF, rather than HbA1c, is independently associated with increased DKD prevalence and impaired renal function.