Table 2.
Intradialytic changes of plasma concentrations of arginine, guanidinoacetate, creatine and creatinine
| Metabolite | Total cohort | Males | Females | P-value |
|---|---|---|---|---|
| Arginine | ||||
| Predialysis concentration, μmol/L | 77 ± 22*** | 80 ± 24*** | 72 ± 18*** | 0.2 |
| Postdialysis concentration, μmol/L | 60 ± 19*** | 63 ± 21*** | 55 ± 14*** | 0.08 |
| Absolute decrease, μmol/L | 17 ± 23*** | 17 ± 25*** | 16 ± 19*** | 0.9 |
| Proportional decrease, % | 18 ± 25*** | 17 ± 28*** | 20 ± 21*** | 0.7 |
| Guanidinoacetate | ||||
| Predialysis concentration, μmol/L | 1.8 ± 0.6*** | 1.9 ± 0.6*** | 1.6 ± 0.5 | 0.1 |
| Postdialysis concentration, μmol/L | 1.0 ± 0.3*** | 1.1 ± 0.3*** | 0.9 ± 0.4 | 0.07 |
| Absolute decrease, μmol/L | 0.8 ± 0.4*** | 0.8 ± 0.5*** | 0.7 ± 0.4*** | 0.4 |
| Proportional decrease, % | 40 ± 17*** | 38 ± 17*** | 43 ± 15*** | 0.3 |
| Creatine | ||||
| Predialysis concentration, μmol/L | 26 [16–41] *** | 19 [15–33] * | 33 [24–56] *** | 0.01 |
| Postdialysis concentration, μmol/L | 21 [15–30] *** | 20 [15–25] * | 24 [15–37] *** | 0.01 |
| Absolute decrease, μmol/L | 5 [1–14] *** | 3 [0–8] * | 10 [3–18] *** | 0.02 |
| Proportional decrease, % | 13 ± 39* | 5 ± 43 | 27 ± 26*** | 0.02 |
| Creatinine | ||||
| Predialysis concentration, μmol/L | 689 ± 207*** | 706 ± 224*** | 660 ± 175*** | 0.4 |
| Postdialysis concentration, μmol/L | 257 ± 92*** | 274 ± 97*** | 228 ± 78*** | 0.07 |
| Absolute decrease, μmol/L | 432 ± 146*** | 432 ± 156*** | 432 ± 130*** | 0.9 |
| Proportional decrease, % | 63 ± 8*** | 61 ± 9*** | 65 ± 7*** | 0.05 |
Differences between males and females are tested using an independent sample t-test. Differences between predialysis and postdialysis plasma concentrations are tested using paired sample t-test or the paired samples Wilcoxon test. Absolute decrease and proportional decrease are test against no decrease by t-test or Wilcoxon test. Statistical significance is indicated with asterixis (* P < 0.05; ** P < 0.01; *** P < 0.001)