Association between a body shape index and diabetic kidney disease in patients with diabetes mellitus: a cross-sectional study from the 2005–2016 U.S. National Health and Nutrition Examination Survey

Uncertainty persists regarding the associations between a body shape index (ABSI) and diabetic kidney disease (DKD), albuminuria, and low estimated glomerular filtration rate (eGFR). Data from 2,770 participants in the 2005-2016 U.S. National Health and Nutrition Examination Survey (NHANES) were analyzed in this study. Multiple logistic regression models and subgroup analyses were utilized to evaluate the relationships between ABSI and DKD, albuminuria, and low eGFR. A restricted cubic spline (RCS) plot was applied to examine trends in these associations. In the fully adjusted model, each unit increase in ABSI was associated with a 33% higher risk of DKD (adjusted OR = 1.33, 95% CI: 1.09-1.61, <i>p</i> = 0.0043) and a 50% higher risk of albuminuria (adjusted OR = 1.50, 95% CI: 1.23-1.84, <i>p</i> < 0.0001). In contrast, no significant relationship was observed with low eGFR (adjusted OR = 1.13, 95% CI: 0.88-1.46, <i>p</i> = 0.3444). These relationships exhibited variation across age, sex, and comorbidity subgroups. Results based on standardized ABSI (z-score) were similar, confirming significant associations with DKD and albuminuria. RCS plots showed that ABSI was significantly and linearly associated with the risks of DKD (P-overall = 0.026, P-nonlinear = 0.577) and albuminuria (P-overall = 0.001, P-nonlinear = 0.658), indicating that the risk of DKD and albuminuria increased with higher ABSI levels. In contrast, no significant association was observed between ABSI and low eGFR (P-overall = 0.298, P-nonlinear = 0.238). Higher ABSI levels are associated with increased risks of DKD and albuminuria, particularly in specific subgroups.