Is a Single Time Point C-Reactive Protein Predictive of Outcome in Peritoneal Dialysis Patients?

Abstract

Abstract. C-reactive protein is the prototype marker of inflammation and has been shown to predict mortality in hemodialysis patients. However, it remains uncertain as to whether a single C-reactive protein level has similar prognostic significance in peritoneal dialysis patients. A single high-sensitivity C-reactive protein (hs-CRP) level was measured in 246 continuous ambulatory peritoneal dialysis patients without active infections at study baseline together with indices of dialysis adequacy, echocardiographic parameters (left ventricular mass index, left ventricular dimensions, and ejection fraction), nutrition markers (serum albumin, dietary intake, and subjective global assessment) and biochemical parameters (hemoglobin, lipids, calcium, and phosphate). The cohort was then followed-up prospectively for a median of 24 mo (range, 2 to 34 mo), and outcomes were studied in relation to these parameters. Fifty-nine patients died (36 from cardiovascular causes) during the follow-up period. The median hs-CRP level was 2.84 mg/L (range, 0.20 to 94.24 mg/L). Patients were stratified into tertiles according to baseline hs-CRP, namely those with hs-CRP Յ 1.26 mg/L, 1.27 to 5.54 mg/L, and Ն 5.55 mg/L. Those with higher hs-CRP were significantly older (P Ͻ 0.001), had greater body mass index (P Ͻ 0.001), higher prevalence of coronary artery disease (P ϭ 0.003), and greater left ventricular mass index (P Ͻ 0.001). One-year overall mortality was 3.9% (lower) versus 8.8% (middle) versus 21.3% (upper tertile) (P Ͻ 0.0001). Cardiovascular death rate was 2.7% (lower) versus 5.2% (middle) versus 16.2% (upper tertile) (P Ͻ 0.0001). Multivariable Cox regression analysis showed that every 1 mg/L increase in hs-CRP was independently predictive of higher all-cause mortality (hazard ratio [HR], 1.02; 95% CI, 1.01 to 1.04; P ϭ 0.002) and cardiovascular mortality (HR, 1.03; 95% CI, 1.01 to 1.05; P ϭ 0.001) in peritoneal dialysis patients. Other significant predictors for all-cause mortality included age (HR, 1.07; 95% CI, 1.04 to 1.10), gender (HR, 0.49; 95% CI, 0.27 to 0.90), atherosclerotic vascular disease (HR, 2.65; 95% CI, 1.46 to 4.80), left ventricular mass index (HR, 1.01; 95% CI, 1.00 to 1.01) and residual GFR (HR, 0.53; 95% CI, 0.38 to 0.75). Age (HR, 1.06; 95% CI, 1.02 to 1.10), history of heart failure (HR, 3.31; 95% CI, 1.36 to 8.08), atherosclerotic vascular disease (HR, 3.20; 95% CI, 1.43 to 7.13), and residual GFR (HR, 0.57; 95% CI, 0.38 to 0.86) were also independently predictive of cardiovascular mortality. In conclusion, a single, random hs-CRP level has significant and independent prognostic value in PD patients.

Peritoneal Albumin and Protein Losses Do Not Predict Outcome in Peritoneal Dialysis Patients

“…Our study reconfirmed that factors like age, serum CRP (31) and serum albumin levels (32) are determinants of survival. Although hypoalbuminaemia may reflect a high inflammatory status that determines outcome (6,7), high peritoneal losses are locally regulated by cytokines like IL-6 and do not correlate with the systematic condition.…”

Dialysis water treated by reverse osmosis decreases the levels of C-reactive protein in uremic patients

“…Patients with obvious clinical inflammation or with temporary vascular catheters presented high CRP levels, demonstrating that uremic patients may show persistent inflammatory activity for multiple reasons. Although this was not a cohort study aiming to evaluate prognostic factors, the finding of increased CRP in patients who eventually died supports previous studies that demonstrated the prognostic power of inflammation markers (24,25). Nevertheless, the albumin levels or nutritional evaluation of patients with higher inflammatory activity did not differ from those observed in the others.…”

“…It is interesting to note that CRP levels after the change of the water purification system correlated closely with the previous CRP levels, suggesting that the patients present a pattern of inflammatory activity dependent on other factors. This fact has been emphasized before, making this protein useful as a prognostic tool, even after single isolated measurements (24,25,35,36), despite a high intra-individual variation (37).…”

Relationship between peritoneal permeability with inflammation and subclinical atherosclerosis in peritoneal dialysis patients

“…Determination of CRP levels is currently recommended by the American Heart Association in all patients at a risk of CVD (15). Also, the decrease in RRF is connected to a stronger inflammatory response in peritoneal dialysis patients with higher concentrations of CRP (16)(17)(18). In our study, CRP was not different between the patients having RRF or not.…”

“…A modified PET using 4.25% glucose dialysate was performed and the value of the dialysate-to-plasma creatinine ratio at 4 h was calculated as previously reported (18). The patients were grouped as high (high+high average) and low (low+low average) transporters according to modified PET test.…”