Lean tissue index and nutritional status in dialysis patients: Insights from a large-scale observational study

Malnutrition and lean tissue loss are common in dialysis patients and are linked to increased morbidity and mortality. Lean Tissue Index (LTI), a measure of muscle mass adjusted for height, offers an objective assessment of nutritional status. However, its relationship with conventional nutritional markers remains poorly defined.

We conducted a retrospective analysis of 365 adult dialysis patients from multiple centers. Baseline data included anthropometrics, body composition (LTI), and nutritional biomarkers: albumin, prealbumin, Geriatric Nutritional Risk Index (GNRI), normalized protein catabolic rate, phosphate, and potassium. Correlation analysis (Pearson/Spearman), multivariate linear regression, and comparative analysis based on LTI classification (LTI2: low vs. high) were performed to evaluate the associations between LTI and nutritional parameters.

Mean age was 70.2 ± 13.3 y; 64.9% were male. The mean LTI was 12.29 ± 3.32 kg/m². LTI showed strong positive correlation with weight (r = 0.85) and moderate associations with albumin (r = 0.50) and GNRI (r = 0.55). Multivariate analysis revealed weight (β = 0.144, P < 0.001), serum albumin (β = 0.241, P = 0.001), prealbumin (β = 0.046, P = 0.015), and potassium (β = 0.800, P < 0.001) levels as independent predictors of LTI. GNRI was inversely associated with LTI (β = -0.170, P < 0.001). Patients in the high-LTI group had significantly higher weight, albumin, prealbumin, and GNRI (all P < 0.05), but no significant differences in normalized protein catabolic rate, phosphate, or potassium.

LTI is strongly associated with conventional nutritional markers, particularly body weight and serum proteins. While GNRI correlates with LTI, it may reflect broader nutritional reserves rather than lean mass specifically. These findings underscore the importance of integrating body composition measurements into routine nutritional assessment in dialysis care.