Dataset Information

Estimated net endogenous acid production and serum bicarbonate in African Americans with chronic kidney disease.

ABSTRACT:

Background and objectives

Metabolic acidosis may contribute to morbidity and disease progression in patients with chronic kidney disease (CKD). The ratio of dietary protein, the major source of nonvolatile acid, to dietary potassium, which is naturally bound to alkali precursors, can be used to estimate net endogenous acid production (NEAP). We tested the association between estimated NEAP and serum bicarbonate in patients with CKD.

Design, setting, participants, & measurements

NEAP was estimated among 462 African American adults with hypertensive CKD using published equations: NEAP (mEq/d) = -10.2 + 54.5 (protein [g/d]/potassium [mEq/d]). Dietary protein and potassium intake were estimated from 24-hour urinary excretion of urea nitrogen and potassium, respectively. All of the eligible measurements during follow-up were modeled using generalized linear regression clustered by participant and adjusted for demographics, 24-hour urinary sodium, kidney function, and selected medications.

Results

Higher NEAP was associated with lower serum bicarbonate in a graded fashion (P trend < 0.001). Serum bicarbonate was 1.27 mEq/L lower among those in the highest compared with the lowest quartile of NEAP (P < 0.001). There was a greater difference in serum bicarbonate between the highest and lowest quartiles of NEAP among patients with stage 4/5 CKD (-2.43 mEq/L, P < 0.001) compared with those with stage 2/3 disease (-0.77 mEq/L, P = 0.01; P-interaction = 0.02).

Conclusions

Reducing NEAP, through reduction of dietary protein and increased intake of fruits and vegetables, may prevent metabolic acidosis in patients with CKD.

SUBMITTER: Scialla JJ

PROVIDER: S-EPMC3552445 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature

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Publications

Estimated net endogenous acid production and serum bicarbonate in African Americans with chronic kidney disease.

Scialla Julia J JJ Appel Lawrence J LJ Astor Brad C BC Miller Edgar R ER Beddhu Srinivasan S Woodward Mark M Parekh Rulan S RS Anderson Cheryl A M CA

Clinical journal of the American Society of Nephrology : CJASN 20110623 7

<h4>Background and objectives</h4>Metabolic acidosis may contribute to morbidity and disease progression in patients with chronic kidney disease (CKD). The ratio of dietary protein, the major source of nonvolatile acid, to dietary potassium, which is naturally bound to alkali precursors, can be used to estimate net endogenous acid production (NEAP). We tested the association between estimated NEAP and serum bicarbonate in patients with CKD.<h4>Design, setting, participants, & measurements</h4>NE ...[more]

PMID: 21700817

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Project description:BackgroundRoutine primary care visits provide an educational opportunity for African-Americans with chronic kidney disease (CKD) and CKD risk factors such as hypertension. The nature of patient-physician discussions about CKD and their impact on CKD awareness in this population have not been well explored.ObjectiveTo characterize patient CKD awareness and discussions about CKD between patients and primary care physicians (PCPs).DesignMixed methods study.PatientsAfrican-American patients with uncontrolled hypertension (≥ 140/90 mmHg) and CKD (albuminuria or eGFR < 60 ml/min/1.73 m2) recruited from an urban primary care clinic.Main measuresWe assessed patient CKD awareness with questionnaires and audio-recorded patients-PCP discussions during a routine visit. We characterized discussions and used multivariate regression analysis to identify independent patient and visit predictors of CKD awareness or CKD discussions.ResultsAmong 48 African-American patients with uncontrolled hypertension and CKD, 29% were aware of their CKD. After adjustment, CKD awareness was associated with moderate-severe CKD (stages 3-4) (vs. mild CKD [stages 1-2]) (prevalence ratio [PR] 2.82; 95% CI 1.18-6.78) and inversely associated with diabetes (vs. without diabetes) (PR 0.28; 95% CI 0.10-0.75). CKD discussions occurred in 30 (63%) visits; most focused on laboratory assessment (n = 23, 77%) or risk factor management to delay CKD progression (n = 19, 63%). CKD discussions were associated with moderate-severe CKD (vs. mild CKD) (PR 1.57; 95% CI 1.04-2.36) and diabetes (vs. without diabetes) (PR 1.42; 95% CI 1.09-1.85), and inversely associated with uncontrolled hypertension (vs. controlled) (PR 0.58; 95% CI 0.92-0.89). In subgroup analysis, follow-up CKD awareness did not change by presence or absence of CKD discussion (10.5% vs. 7.7%, p = 0.8).ConclusionsIn patients at risk of CKD progression, few were aware of CKD, and CKD discussions were not associated with CKD awareness. More resources may be needed to enhance the clarity of clinical messages regarding CKD and its significance for patients' health.Trial registrationClinicalTrials.gov Identifier: NCT01902719.

Project description:Background and objectivesHigh 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.Design, setting, participants, & measurementsWe 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.ResultsThe 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, P=0.001 and hazard ratio, 1.44; 95% confidence interval, 1.24 to 1.69, P<0.001, respectively). Baseline venous bicarbonate mediated 20% of the association between net endogenous acid production using food frequency questionnaires and the kidney end point. Baseline venous bicarbonate, urinary ammonium excretion, and net acid excretion mediated 25%, -14%, and -18%, respectively, of the association between net endogenous acid production using urinary excretion and the kidney end point.ConclusionsHigher 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.

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Project description:BackgroundHigh diet quality is associated with a lower risk of chronic diseases. Metabolomics can be used to identify objective biomarkers of diet quality.ObjectivesWe used metabolomics to identify serum metabolites associated with 4 diet indices and the components within these indices in 2 samples from African Americans and European Americans.MethodsWe studied cross-sectional associations between known metabolites and Healthy Eating Index (HEI)-2015, Alternative Healthy Eating Index (AHEI)-2010, the Dietary Approaches to Stop Hypertension Trial (DASH) diet, alternate Mediterranean diet (aMED), and their components using untargeted metabolomics in 2 samples (n1 = 1,806, n2 = 2,056) of the Atherosclerosis Risk in Communities study (aged 45-64 y at baseline). Dietary intakes were assessed using an FFQ. We used multivariable linear regression models to examine associations between diet indices and serum metabolites in each sample, adjusting for participant characteristics. Metabolites significantly associated with diet indices were meta-analyzed across 2 samples. C-statistics were calculated to examine if these candidate biomarkers improved prediction of individuals in the highest compared with lowest quintile of diet scores beyond participant characteristics.ResultsSeventeen unique metabolites (HEI: n = 6; AHEI: n = 5; DASH: n = 14; aMED: n = 2) were significantly associated with higher diet scores after Bonferroni correction in sample 1 and sample 2. Six of 17 significant metabolites [glycerate, N-methylproline, stachydrine, threonate, pyridoxate, 3-(4-hydroxyphenyl)lactate)] were associated with ≥1 dietary pattern. Candidate biomarkers of HEI, AHEI, and DASH distinguished individuals with highest compared with lowest quintile of diet scores beyond participant characteristics in samples 1 and 2 (P value for difference in C-statistics <0.02 for all 3 diet indices). Candidate biomarkers of aMED did not improve C-statistics beyond participant characteristics (P value = 0.930).ConclusionsA considerable overlap of metabolites associated with HEI, AHEI, DASH, and aMED reflects the similar food components and similar metabolic pathways involved in the metabolism of healthy diets in African Americans and European Americans.

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Dataset Information

Estimated net endogenous acid production and serum bicarbonate in African Americans with chronic kidney disease.

Background and objectives

Design, setting, participants, & measurements

Results

Conclusions

Publications

Estimated net endogenous acid production and serum bicarbonate in African Americans with chronic kidney disease.

Similar Datasets

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