TABLE 2.

Serum known metabolites significantly associated with net endogenous acid production in AASK and the MDRD study¹

			AASK			MDRD
Superpathway	Subpathway	Metabolite	β2	SE	P value	β2	SE	P value
Amino acid	Methionine, cysteine, SAM, and taurine metabolism	S-methylmethionine	−0.054	0.012	5.06 × 10−06	−0.186	0.047	8.18 × 10−05
Amino acid	Tryptophan metabolism	Indolepropionylglycine	−0.061	0.012	2.25 × 10−07	−0.144	0.032	6.90 × 10−06
Amino acid	Tryptophan metabolism	Indolepropionate	−0.061	0.011	6.65 × 10−08	−0.109	0.027	8.34 × 10−05
Amino acid	Urea cycle; arginine and proline metabolism	N-methylproline	−0.120	0.015	3.34 × 10−15	−0.172	0.032	9.15 × 10−08
Amino acid	Urea cycle; arginine and proline metabolism	N-δ-acetylornithine	−0.043	0.006	8.29 × 10−12	−0.071	0.016	1.31 × 10−05
Cofactors and vitamins	Ascorbate and aldarate metabolism	Threonate	−0.048	0.006	5.13 × 10−15	−0.044	0.013	1.12 × 10−03
Cofactors and vitamins	Ascorbate and aldarate metabolism	Oxalate (ethanedioate)	−0.041	0.005	9.72 × 10−16	−0.033	0.010	1.14 × 10−03
Lipid	Inositol metabolism	Chiro-inositol	−0.145	0.020	4.13 × 10−13	−0.127	0.035	3.38 × 10−04
Xenobiotics	Bacterial/fungal	Tartronate (hydroxymalonate)	−0.079	0.009	2.45 × 10−17	−0.038	0.012	1.19 × 10−03
Xenobiotics	Benzoate metabolism	Catechol sulfate	−0.039	0.008	3.84 × 10−06	−0.104	0.020	2.36 × 10−07
Xenobiotics	Benzoate metabolism	Hippurate	−0.042	0.010	1.33 × 10−05	−0.086	0.024	3.15 × 10−04
Xenobiotics	Food component/plant	Methyl glucopyranoside (α + β)	−0.118	0.012	8.04 × 10−22	−0.156	0.025	1.82 × 10−09
Xenobiotics	Food component/plant	Stachydrine	−0.123	0.015	6.40 × 10−16	−0.188	0.034	8.86 × 10−08

¹Statistical significance was assessed using Bonferroni method to account for multiple comparisons (AASK: P < 6.6 × 10⁻⁵; MDRD: P < 2.2 × 10⁻³). AASK, African American Study of Kidney Disease and Hypertension; MDRD, Modification of Diet in Renal Disease.

²β-coefficients are expressed per 10 mEq/d higher net endogenous acid production.