# The association between the extracellular water-to-total body water ratio and albuminuria in Chinese type 2 diabetes mellitus patients

## TL;DR

This study shows that a body water ratio measured by BIA is linked to kidney damage in Chinese type 2 diabetes patients and could help detect early kidney disease.

## Contribution

The study introduces ECW/TBW as a potential early diagnostic marker for macroalbuminuria in T2DM patients with normal or mildly impaired kidney function.

## Key findings

- ECW/TBW increased significantly with higher urine albumin-creatinine ratio (UACR) levels in T2DM patients.
- ECW/TBW was significantly associated with macroalbuminuria in patients with eGFR ≥ 60 mL/min/1.73 m2.
- Nomograms with good predictive accuracy were developed to identify macroalbuminuria from normoalbuminuria and microalbuminuria.

## Abstract

Diabetic kidney disease (DKD) is a common complication in patients with type 2 diabetes (T2DM), and early screening and diagnosis are crucial for preventing end-stage renal disease (ESRD). The extracellular water/total body water (ECW/TBW), as measured by bioelectrical impedance analysis (BIA), may be closely associated with the development of DKD. This study aimed to evaluate the relationship between ECW/TBW and albuminuria in T2DM patients and to explore its potential as an early diagnostic tool.

This study included 1,034 T2DM patients. Demographic information, medical history, medication use, and laboratory test results were collected, including glycated hemoglobin (HbA1c), creatinine, lipid profile, and the urine albumin-creatinine ratio (UACR). BIA was used to measure parameters such as ECW/TBW. Multivariate logistic regression analysis explored the correlation between ECW/TBW and UACR. Ultimately, two simple nomograms were established to predict macroalbuminuria from patients with normoalbuminuria and microalbuminuria, respectively.

The ECW/TBW increased significantly with rising UACR levels. Multivariate logistic regression analysis showed that ECW/TBW was significantly associated with macroalbuminuria compared to both normo-albuminuria and microalbuminuria (OR = 2.082, 95% CI [1.476–2.937], P < 0.001; and OR = 1.642, 95% CI [1.129–2.386], P = 0.009, respectively). In the analysis stratified by renal function, a similar relationship was found only in patients with eGFR ≥ 60 mL/min/1.73 m2 (OR = 2.108, 95% CI [1.479–3.004], P < 0.001) but not in patients with eGFR < 60 mL/min/1.73 m2. Finally, two nomograms for predicting macroalbuminuria were established. The C-index of the nomogram model for predicting the macroalbuminuria in patients with normoalbuminuria was 0.795 (95% CI [0.752–0.838]), and the C-index of the nomogram model for predicting the macroalbuminuria in patients with microalbuminuria was 0.761 (95% CI [0.711–0.812]).

This study demonstrated a significant correlation between the ECW/TBW and UACR levels in Chinese T2DM patients. In patients with normal or mildly impaired renal function (eGFR ≥ 60 mL/min/1.73 m2), ECW/TBW was significantly associated with macroalbuminuria, potentially serving as a diagnostic marker for macroalbuminuria.