Inflammation in patients on peritoneal dialysis is associated with increased extracellular fluid volume.

Background: Cardiovascular disorders (CD) are the most frequent cause of death in patients on dialysis. CD have been related to increased extracellular fluid volume, peritoneal transport type (PTT), hypertension, and inflammation. Inflammation is in itself a risk factor for mortality. The aim of this study was to assess the relationship of increased extracellular fluid volume, inflammation, and PTT in patients on continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD).

Methods: A cross-sectional study was carried out with 20 healthy controls (C), 21 patients on CAPD, and nine patients on APD. Clinical and demographic variables were measured and registered. Peritoneal equilibrium test (PET) was done. Blood volume (BV), total body water (TBW), inferior vena cava diameter during inspiration (IVCDi) and expiration (IVCDe), serum albumin, and serum C-reactive protein (CRP) were measured.

Results: All patients on peritoneal dialysis (PD) had at least one sign or symptom of increased extracellular fluid volume, hypertension being the most common. Patients also had higher TBW (C, 60.7 +/- 7.2; APD, 62.6 +/- 8.7; CAPD, 66.1 +/- 8.3, as percentage of body weight, p <0.02), higher BV (C, 7.9 +/- 1.6; APD, 9.8 +/- 2.3; CAPD, 9.6 +/- 2.3, as percentage of body weight, p <0.02), higher DIVCi (C, 2.9 +/- 1.2; APD, 4.6 +/- 2.5; CAPD, 4.5 +/- 2.4 mm/m2 BSA, p <0.02), and higher DIVCe (C, 6.2 +/- 1.7; APD, 8.3 +/- 3.4; CAPD, 8.0 +/- 2.8 mm/m2 BSA, p <0.05). PD patients also had hypoalbuminemia and higher CRP levels. There was significant positive correlation between CRP and DIVCi (r=0.43, p <0.05) and IVCe (r=0.45, p <0.05) and between serum albumin and creatinine dialysate-to-plasma ratio (D/P Cr, r=0.57, p <0.01). Serum albumin and CRP were negatively correlated (r= -0.54, p <0.02).

Conclusions: Patients on PD have increased extracellular fluid volume as compared with healthy controls. Hyperhydration is related to inflammation and to higher peritoneal transport types.