Relationship of peritoneal transport rate and dialysis adequacy with inflammation in peritoneal dialysis patients

Inflammation, dialysis adequacy, and peritoneal transport rate (PTR) influence clinical outcomes in peritoneal dialysis (PD) patients. The present study examined the relationship of C-reactive protein (CRP), a marker of inflammation, to PTR and residual renal function (RRF) in PD patients. We recorded the baseline dialysate-to-plasma creatinine (D/P Cr) of 210 PD patients starting in 1986. In a subgroup of 42 patients, we serially measured high-sensitivity CRP levels and.dialysis adequacy, including weekly Kt/V urea and creatinine clearance (CCr), starting in May 2003. The patients were followed to January 2006. Mean age was 53 +/- 16 (standard deviation) years, and 70% of the patients were African American. Enrollment mean and median CRP levels were 13.53 +/- 20.8 (range: 0.2-95.8) and 7.15 mg/L respectively. Mean weekly residual CCr and Kt/V during follow-up were 7.11 +/- 15.47 L/1.73 m2 and 0.14 +/- 0.30 respectively. The mean enrollment D/P Cr was 0.649 +/- 0.12 (range: 0.429-0.954). Patients with CRP > 10 mg/L had significantly lower weekly residual CCr (0.59 L/1.73 m2 vs. 10.1 L/1.73 m2, p = 0.01), residual Kt/V (0.01 vs. 0.20, p = 0.01), total CCr (56 L/1.73 m2 vs. 62 L/1.73 m2, p= 0.047), and total Kt/V (2.09 vs. 2.49, p = 0.001) than did those with CRP < or = 10 mg/L. Levels of CRP correlated negatively with weekly residual CCr (r = -0.42, p = 0.006), residual Kt/V (r = -0.43, p = 0.006), and total Kt/V (r = -0.44, p = 0.004). Enrollment D/P Cr was inversely correlated with serum albumin (r = -0.24, p = 0.001) and directly correlated with peritoneal protein loss (r = 0.34, p = 0.028). Higher enrollment D/P Cr was associated with lower observed cumulative survival (Kaplan-Meier) in PD patients. However D/P Cr was not an independent predictor of long-term survival in PD patients. Using multivariate Cox regression analysis, and including D/P Cr and residual Kt/V in the model, enrollment CRP was an independent predictor of mortality (relative risk = 1.036, p = 0.018). We conclude that elevated CRP is associated with lower RRF As a predictor of mortality, CRP may be better than RRF and D/P Cr.