Search

High dietary acid load may accelerate a decline in kidney function. We prospectively investigated whether dietary acid load is associated with graft outcomes in kidney transplant recipients, and whether venous bicarbonate mediates this association.We used data from 642 kidney transplant recipients with a functioning graft ≥1 year after transplantation. Net endogenous acid production was estimated using food frequency questionnaires and, alternatively, 24-hour urinary urea and potassium excretion to estimate net endogenous acid production. We defined the composite kidney end point as a doubling of plasma creatinine or graft failure. Multivariable Cox regression analyses, adjusted for potential confounders, were used to study the associations of dietary acid load with the kidney end point. We evaluated potential mediation effects of venous bicarbonate, urinary bicarbonate excretion, urinary ammonium excretion, titratable acid excretion, and net acid excretion on the association between net endogenous acid production and the kidney end point.The median net endogenous acid production using food frequency questionnaires and net endogenous acid production using urinary excretion were 40 (interquartile range, 35-45) and 54 (interquartile range, 44-66) mEq/day, respectively. During a median follow-up of 5.3 years (interquartile range, 4.1-6.0), 121 (19%) participants reached the kidney end point. After multivariable adjustment, net endogenous acid production using food frequency questionnaires and net endogenous acid production using urinary excretion (per SD higher) were independently associated with higher risk for kidney end point (hazard ratio, 1.33; 95% confidence interval, 1.12 to 1.57,Higher dietary acid load was associated with a higher risk of doubling of plasma creatinine or graft failure, and this association was partly mediated by venous bicarbonate, urinary ammonium, and net acid excretion.

Background and objectives We examined the effect of alkali replacement for metabolic acidosis on vascular endothelial function in patients with CKD. Methods We performed a pilot, prospective, open-label 14-week crossover study examining the effect of oral sodium bicarbonate treatment on vascular function in 20 patients with an eGFR of 15–44 ml/min per 1.73 m 2 with low serum bicarbonate levels (16–21 mEq/L). Each period was 6 weeks in duration with a 2-week washout period in between. Patients were treated to goal serum bicarbonate of ≥23 mEq/L. The primary end point was change in brachial artery flow-mediated dilation (FMD) between treatment and control conditions. Secondary end points included changes in markers of inflammation, bone turnover, mineral metabolism, and calcification. Results Eighteen patients completed the study and were included in the primary efficacy analysis. The mean (SD) age and eGFR were 59 (12) years and 26 (8) ml/min per 1.73 m 2 , respectively. Serum bicarbonate increased significantly with sodium bicarbonate treatment (+2.7±2.9 mEq/L, P ≤0.001), whereas there was no change in bicarbonate levels in the control group. FMD significantly improved after sodium bicarbonate therapy (mean±SD, FMD baseline: 4.1%±4.1%; 6 weeks: 5.2%±2.9%; P =0.04) There was no significant change in FMD in the control group (mean±SD, FMD baseline: 4.6%±3.1%; 6 weeks: 4.1%±3.4%; P =0.20). Compared with control, sodium bicarbonate treatment resulted in a significant increase in FMD (mean, 1.8%; 95% confidence interval, 0.3 to 3.3; P =0.02). There was no significant change in bone markers or serum calcification propensity with treatment. Serum phosphorus and intact fibroblast growth factor 23 increased significantly during treatment. Conclusions Treatment of metabolic acidosis with sodium bicarbonate significantly improved vascular endothelial function in patients with stages 3b and 4 CKD.

Neuromuscular complications are almost universal in CKD by the time that a patient commences dialysis. Recent studies have indicated that chronic hyperkalemia may contribute to the development of neuropathy in CKD. This study was undertaken to determine whether dietary restriction of potassium intake may be a neuroprotective factor in CKD.A 24-month prospective, single-blind, randomized, controlled trial was undertaken in 47 consecutively recruited patients with stages 3 and 4 CKD. The intervention arm (There was a greater increase in total neuropathy score from baseline to final assessment in the control arm compared with the intervention arm (6.1±6.2-8.6±7.9 controls; 7.8±7.4-8.2±7.5 intervention; change 2.8±3.3-0.4±2.2, respectively;Our results provide important preliminary evidence that dietary potassium restriction confers neuroprotection in CKD and should be confirmed in a larger multicenter trial.