Table 1.
Subject characteristics and significant differences in plasma metabolites and metabolite ratios by CKD cohort (median and interquartile range)
| Variables | CKD stage 2 (n=20) | CKD stage 3b (n=20) | P | ||
|---|---|---|---|---|---|
| mGFR (ml/min per 1.73 m2) | 74.3 (67.4, 82.9) | 32.8 (24.3, 35.5) | < 0.001a | ||
| Age, yr | 15.0 (12.7, 15.7) | 14.8 (11.7, 16.1) | 0.59 | ||
| Body mass index (BMI) Z | 0.95 (-0.07, 1.63) | 0.34 (-0.10, 0.82) | 0.79 | ||
| Serum PTH (pg/ml) | 33.0 (26.0, 50.2) | 60.0 (37.3, 197.0) | 0.03a | ||
| Urine Pro/Cr ratio | 0.34 (0.14, 1.76) | 0.63 (0.16, 1.58) | 0.56 | ||
| Metabolites | CKD stage 2 | CKD stage 3b | T statistic | P | FDR |
| SDMA | ↑ | −5.6057 | 1.98E-06 | 3.09E-04 | |
| PC ae (C32:1) | ↑ | 4.4398 | 7.50E-05 | 5.85E-03 | |
| Kynurenine | ↑ | −4.2039 | 1.54E-04 | 7.98E-03 | |
| Creatinine | ↑ | −3.9549 | 3.23E-04 | 1.26E-02 | |
| C4:1 | ↑ | 3.5496 | 1.05E-03 | 3.27E-02 | |
| Metabolite ratios | |||||
| Tyr/Cr | ↑ | 5.3733 | 4.12E-06 | 2.47E-05 | |
| Orn/Cit | ↑ | 4.2933 | 1.17E-04 | 3.52E-04 | |
| Kyn/Trp | ↑ | −4.112 | 2.02E-04 | 4.05E-04 | |
| Pro/Cit | ↑ | 3.7856 | 5.30E-04 | 7.96E-04 | |
| SDMA/ADMA | ↑ | −3.5173 | 1.15E-03 | 1.38E-03 |
Body mass index (weight in kg/height in meters2) corrected for gender and age. The arrows indicate which metabolites and ratios were higher in CKD Stage 2 or 3b cohort.
ADMA, asymmetric dimethylarginine; Cit, citrulline; CKD, chronic kidney disease; Cr, creatinine; C4:1, butenoylcarnitine (fatty acylcarnitine); FDR, false discovery rate (5% of significant tests will result in false positives); Kyn, kynurenine; mGFR, measured glomerular filtration rate; Orn, ornithine; PCae (C32:1), phosphatidylcholine with acyl-akyl residue; Pro, proline; PTH, parathyroid hormone; SDMA, symmetric dimethylarginine; Trp, tryptophan; Tyr, tyrosine.
Differences between the CKD cohorts were considered to be significant when P < 0.001.