Presentation description

High dietary acid load contributes to worsening kidney function by promoting kidney fibrosis in persons with established chronic kidney disease (CKD). The Dietary Acid Load Study (DETAIL) is investigating whether clinically-available measures of diet acidity are associated with measures of kidney fibrosis, kidney damage, and oxidative stress in US Veterans at risk for but do not have CKD. DETAIL is enrolling 260 US Veterans with a history of diabetes and/or hypertension but who have normal kidney function. We conducted an interim analysis of 39 participants to determine the associations between urinary ammonium (measure of diet acidity), urinary citrate (measure of diet alkalinity), and serum bicarbonate (measure of systemic acid-base balance) with kidney fibrosis, kidney tubule damage, and oxidative stress markers. Kidney fibrosis markers are urinary transforming growth factor-β1 (TGF-β1) and fibronectin; kidney tubule damage markers are urinary kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL); and oxidative stress markers are serum and urinary 8-hydroxydeoxyguanosine (8-OHdG, oxidative DNA damage marker) and 8-isoprostane (lipid peroxidation marker). Participant characteristics are mean (SD) age 56 (13) years, 95% male, 24-hour urinary ammonium 48 (26) mEq/d, 24-hour urinary citrate 788 (436) mg/d, and serum bicarbonate 24 (2) mEq/L. Using the lowest tertile of each acid-base indicator as the reference group, we identified statistically significant associations between urinary ammonium and serum bicarbonate with urinary fibronectin levels using linear regression models adjusted for age, body mass index (BMI), and urine creatinine. There were no other statistically significant associations between ammonium, citrate, and bicarbonate with the other measurements. The study is continuing to enroll participants, therefore, no definitive conclusions can be made. The study seeks to determine whether clinically-available measures can identify individuals at risk of acid-mediated kidney damage and consequently CKD.