Dietary Behaviors and Urinary Biomarkers in a Self-Management Support Program Among Low-Income Adults with CKD.

BACKGROUND: CKD disproportionately affects socioeconomically disadvantaged populations, among whom adoption of kidney-friendly diets is often constrained by structural barriers. Self-management support (SMS) programs can improve CKD awareness and cardiovascular risk factors; however, their ability to influence dietary behaviors and diet-related physiologic markers when nutrition content is limited remains uncertain. We evaluated whether participation in a culturally tailored SMS program with modest dietary education was associated with changes in self-reported dietary behaviors and urinary biomarkers among low-income adults with CKD. METHODS: We conducted a secondary exploratory analysis of a randomized controlled trial (NCT01530958) among low-income adults with early-to-moderate CKD. Participants were randomized to an SMS program that included limited dietary education focused on reducing sodium, refined sugar, and fast-food consumption. Outcomes included self-reported intake of soda, fruit-flavored drinks, and fast food, as well as urinary biomarkers reflecting sodium-potassium balance and inflammation, including sodium-to-potassium ratio (Na/K), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and transforming growth factor-β1 (TGF-β1). Multivariable linear regression models adjusted for sociodemographic characteristics and body mass index were used to assess associations at intervention completion and 6-month follow-up. RESULTS: Among 266 participants (mean age 57.5 years; 51% men; 34% African American, 36% Hispanic, 19% Asian/Pacific Islander, and 9% non-Hispanic White), 97% reported annual household income below $50,000. The intervention was not associated with significant changes in self-reported dietary behaviors, urinary Na/K ratio (β [95% CI]: 0.24 [ -0.61, 1.09]), urinary IL-6 (-1.86 [-4.96, 1.25]), or urinary TGF-β1 (5.41 [-1.08, 11.54]). A modest reduction in urinary TNF-α was observed (-0.24 [-0.43, -0.02]). CONCLUSIONS: In this low-income CKD population, an SMS program with limited dietary content was not sufficient to produce measurable changes in dietary behaviors or most diet-related urinary biomarkers. These findings underscore the need for more intensive, nutrition-focused, and structurally supported interventions to achieve meaningful dietary and physiologic change in CKD.