Association of 24-Hour Urinary Citrate with Cardiovascular Disease in Kidney Transplant Recipients

Background: Hypocitraturia is a risk factor for kidney stones in kidney transplant recipients (KTR), but whether hypocitraturia is associated with cardiovascular or allograft disease in KTR is unclear. We examined whether 24-hour urinary citrate excretion was associated with estimated GFR and cardiovascular disease (CVD) in KTR. Methods: We studied 54 stable KTR with a functioning allograft ≥1 year. Urinary citrate excretion was determined from a 24-hour urine collection. Finger reactive hyperemic index (RHI) and aortic pulse wave velocity (PWV), both of which are predictors of CVD outcomes, were determined using EndoPAT (peripheral artery tonometry) and Sphygmocor, respectively. Linear regression was used to evaluate the association between urinary citrate excretion with RHI, PWV and estimated GFR. Results: The mean (SD) age and eGFR were 50.0 (14.8) years and 66.5 (16.8) ml/min/1.73m2. 75.9% were men and 25.9% had diabetes. Mean (SD) 24-hour urinary citrate was 285.2 (208.2) mg/day. 24-hour urinary citrate excretion was not significantly associated with RHI, PWV or EGFR in unadjusted or fully adjusted analyses (Table 1). A trend towards significance was seen in the association between urinary citrate with PWV and eGFR. Conclusion: 24-hour urinary citrate excretion was not associated with PWV, RHI or eGFR. Whether urinary citrate excretion predicts CVD or allograft outcomes in KTR needs to be determined in larger studies. Funding: NIDDK Support - Unadjusted β-estimate (95% CI) Fully Adjusted* β-estimate (95% CI) RHI -0.003 (-0.001 to 0.0001), p=0.13 -0.0003 (-0.001 to 0.0001), p=0.17 PWV 0.002 (-0.00 to 0.005), p=0.06 0.002 (-0.00 to 0.003), p=0.08 eGFR 0.025 (-0.00 to 0.05), p=0.06 0.025 (-0.00 to 0.05), p=0.06 *Adjusted for age, sex, race/ethnicity, diabetes and hypertension