Association between serum osmolality and chronic kidney disease prevalence: Evidence from NHANES 1999-2018

Chronic kidney disease (CKD) is a significant global public health issue, and early identification of risk factors is critical for prevention and intervention. In recent years, serum osmolality has attracted attention as a potential biomarker; however, its association with CKD remains insufficiently understood.

This study analyzed data from the National Health and Nutrition Examination Survey (NHANES) conducted between 1999 and 2018, including 49,008 participants. The association between serum osmolality levels and CKD prevalence was evaluated using multivariable logistic regression models and restricted cubic spline (RCS) analysis to explore both linear and nonlinear relationships. Subgroup and interaction analyses were performed to assess the applicability of the findings across different populations.

A total of 9,422 participants were diagnosed with CKD. The unadjusted model showed a significant positive association between serum osmolality levels and CKD prevalence (OR: 1.11, 95% CI 1.10-1.12, P < 0.001). In the fully adjusted model (Model 3), the association remained significant (OR: 1.18, 95% CI: 1.17-1.20, P < 0.001). Quartile analysis revealed that participants in the highest quartile (Q4) had a significantly higher risk of CKD compared to those in the lowest quartile (Q1) (OR: 3.97, 95% CI 3.38-4.66, P < 0.001). The trend test indicated a significant positive association between serum osmolality and CKD prevalence (P for trend < 0.001). RCS analysis further confirmed this positive association and identified a nonlinear relationship (P for non-linearity < 0.001). Subgroup analysis showed that the association remained consistent across subgroups, while interaction analysis revealed significant interaction effects for age, gender, and hypertension.

This study demonstrates a significant positive association between serum osmolality levels and CKD prevalence, with broad applicability. Serum osmolality may serve as a potential marker for CKD risk assessment. These findings provide new insights for CKD risk evaluation and management.