Serum albumin in continuous peritoneal dialysis: Its predictors and relationship to urea clearance

Serum albumin in continuous peritoneal dialysis: Its predictors and relationship to urea clearance. We investigated the predictors of serum albumin and the relationship between serum albumin and urea kinetic indices in continuous peritoneal dialysis (CPD). In a training set (TS) of 143 urea kinetic studies performed in 92CPD patients, stepwise logistic regression identified high/high-average peritoneal solute transport, diabetes, advanced age and high daily drain volume normalized by body water as predictors of low serum albumin ( 61 years) to 6.792 (high/high-average transport). The RR with two risk factors present ranged from 5.200 to 9.729. The RR with all three risk factors present was 9.100 (95%CI, range 3.923 to 21.111). A subset of 37CPD patients had a second urea kinetic study 8 ± 5 months after an increase in the amount of dialysis due to low urea clearance and/or uremic symptoms. The weekly KT/V urea increased from 1.40 ± 0.24 to 2.10 ± 0.31 after the increase in the CPD dose. With the increase in dialysis, the protein catabolic rate increased substantially; however, the mean serum albumin remained stable (from 33.9 ± 4.6 to 33.3 ± 6.2 g/liter; decrease 18; increase 15; same 4). In comparison to the subjects who had a decrease in serum albumin after the increase in KT/V, those with the increase in serum albumin were younger (44.2 ± 11.2 vs. 54.3 ± 16.2 years, P = 0.044) and had a higher serum urea after the increase in the dose of CPD (22.4 ± 7.8 vs. 17.0 ± 6.0 mmol/liter, P = 0.037). We conclude that the major predictors of low serum albumin in CPD are advanced age, diabetes, and high/high-average peritoneal solute transport, but not urea kinetic studies. An increase in the dose of dialysis does not cause a consistent rise in serum albumin in underdialyzed CPD subjects. However, a subset of younger patients may be able to increase their serum albumin in response to the increase in KT/V.