Chronic kidney disease and high eGFR according to body composition phenotype in adults with normal BMI

Body composition contributes to the risk of chronic kidney disease (CKD) and glomerular hyperfiltration. In adults with normal body mass index (BMI), the relationships of body composition with CKD and high estimated glomerular filtration rate (eGFR) are largely unknown.

We analyzed 10,734 adults from the Korean National Health and Nutrition Examination Survey (KNHANES), whose body mass index (BMI) was within the normal range (18.5-24.9 kg/m²). Body composition was categorized into four phenotypes (normal, sarcopenia alone, obesity alone, and sarcopenic obesity) based on appendicular lean mass index (ALMI) and total body fat percentage (TBF%) measured by dual-energy X-ray absorptiometry (DXA). We examined the relationship of CKD and high eGFR (eGFR ≥ 120 ml/min per 1.73 m²) with body composition phenotypes. Sarcopenia alone (14.3%), obesity alone (16.0%), and sarcopenic obesity (10.7%) were prevalent. The association between sarcopenia alone and eGFR was J-shaped, while that between sarcopenic obesity and eGFR was U-shaped. In multivariate logistic regression analysis compared with the normal phenotype, sarcopenic obesity had an elevated odds ratio (OR) for CKD (OR: 1.59, 95% CI: 1.16-2.19). Sarcopenia alone (OR: 1.87; 95% CI: 1.41-2.47) and sarcopenic obesity (OR: 2.37, 95% CI: 1.68-3.36) had elevated OR for high eGFR.

These findings suggest that decreased muscle mass and coexistence with excess adiposity show associations with CKD and high eGFR even in adults with normal BMI. Body composition measured by DXA could provide information on the relationship of body composition with CKD and high eGFR.