The usual calculation of body mass index (BMI) can be misleading in patients with advanced chronic kidney disease (CKD) because their altered fluid balances may not be reflected. We obtained corrected BMI (cBMI) and corrected geriatric nutritional risk index (cGNRI) values and investigated whether the 200/5 kHz impedance ratio (IR), measured using bioimpedance spectroscopy, was associated with cGNRI in older patients with non-dialysis CKD stage 5 (CKD5-ND).
Patients over 65 years old (n = 118) were divided into groups by cGNRI tertiles. The differences between the correlations were tested using Steiger’s Z test. The IR and cBMI were used as both continuous and categorical variables in the regression analyses to determine the factors that were independently associated with the cGNRI.
Patients in the third cGNRI tertile had a significantly lower mean IR than those in the other two tertiles (P < 0.001). Across the three cGNRI tertile groups, the IR was incrementally lower in the higher cGNRI tertiles (P for trend < 0.001). The Steiger's Z test showed that the IR had a significantly stronger correlation with cGNRI than the correlation between cBMI and cGNRI. In the multivariable linear regression analyses, the IR was independently associated with the cGNRI, after adjusting for various confounders.
The current results revealed that the IR was a more sensitive indicator of nutritional risk than BMI and was independently associated with cGNRI in older patients with CKD5-ND. Our study suggests that the IR is an appropriate tool for nutritional risk screening. This article is protected by copyright. All rights reserved.