Associations between iron status and diabetic kidney disease: A nationwide study.

Background and aim: Iron status plays a crucial role in various physiological processes, and its dysregulation is associated with numerous health conditions. However, research on the relationship between iron status and diabetic kidney disease (DKD) is quite limited. Therefore, this study aims to investigate the connection between iron status and DKD.

Methods and results: This population-based cross-sectional survey included adult diabetes patients from five National Health and Nutrition Examination Survey (NHANES) cycles spanning 1999 to 2006 and 2017 to 2018. Regression models were used to assess the impact of iron status on the prevalence of diabetic nephropathy. Restricted cubic spline models further explored potential nonlinear dose-response relationships. Subgroup analyses clarified the effects of other covariates on these associations. Iron and TIBC were negatively correlated with DKD, albuminuria, and low estimated glomerular filtration rate (eGFR). TSAT was negatively correlated with DKD and showed an "L"-shaped nonlinear correlation with albuminuria and low-eGFR. Ferritin exhibited a "J"-shaped nonlinear correlation with DKD, albuminuria, and low-eGFR. Subgroup analysis revealed that the association between TIBC and reduced risk of low eGFR was more pronounced in individuals with hypertension. The associations between iron and TSAT with a reduced risk of DKD were more significant in smokers, while the association between ferritin and an increased risk of albuminuria was also more pronounced in smokers.

Conclusions: In diabetic patients, iron status is closely associated with DKD. Monitoring these iron status markers can help improve the prevention and management of kidney health in diabetic patients.