P and R-values for Spearman correlations between the solute concentrations and the different patient characteristics.

Crea: creatinine, ADMA: asymmetric dimethylarginine, SDMA: symmetric dimethylarginine, UA: uric acid, β2M: beta-2-microglobulin, HA: hippuric acid, IS: indoxyl sulfate, IAA: indole acetic acid, PCS: p-cresylsulfate, PCG: p-cresylglucuronide, CMPF: 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid. BW: body weight, PNA: protein equivalent of nitrogen appearance, RRF: residual renal function. P<0.05 is indicated in bold. R values only shown in case of significant P.