The Time Course of Serum C-Reactive Protein is More Predictive of Mortality than its Baseline Level in Peritoneal Dialysis Patients

Abstract

Background Several recent studies reported that a high baseline serum C-reactive protein (CRP) is a powerful predictor of mortality in dialysis patients. However, the acute-phase response is intermittent and not a continuous feature in an individual patient. The aim of this prospective study was to determine whether serial analysis of serum CRP during follow-up allows better prediction of mortality and echocardiographic cardiac disease than a single baseline measurement in peritoneal dialysis (PD) patients. Methods 97 PD patients were monitored for 3 years from the beginning of the treatment. We evaluated the effect of demographic features, comorbidity, blood pressure, blood biochemistry, including CRP, residual renal function, and indices of dialysis adequacy, on mortality and left ventricular hypertrophy (LVH). Cox regression analysis using both the baseline and the averaged values of the study parameters was carried out to determine factors predicting mortality. Logistic regression analysis was performed to determine which factors were independently predictive for LVH and the type of time course of serum CRP. Results Baseline serum CRP was elevated in 29 patients (29.9%). While serum CRP exhibited a stable course (normal or high) in 55 patients (56.7%), it varied considerably over time in 42 patients (43.2%). In the Cox models, both the averaged serum CRP and the type of variability of CRP were predictors of mortality. On the contrary, baseline CRP did not affect adjusted survival. The averaged CRP was also an independent factor affecting LVH, but baseline CRP was not. Age, comorbidity index, instilled dialysate glucose concentration, and Kt/V urea were independently associated with the type of time course of serum CRP. Conclusion The averaged value of serum CRP is more predictive of prognosis compared to the baseline value in PD patients. Determining serum CRP on a regular basis may be helpful to detect early signs of tissue damage or asymptomatic inflammation.

The impact of peritoneal dialysis-related peritonitis on mortality in peritoneal dialysis patients

“…On the one hand, the impaired host defence due to the long-term exposure of the conventional glucose dialysate and malnutrition [ 26 – 29 ] may be the main contributor to the poor outcomes in long-term PD patients when exposed to an episode of peritonitis, although this notion needs to be clarified. On the other hand, a longer duration of PD may also be associated with chronic inflammation [ 30 – 32 ] and cardiovascular calcification [ 33 , 34 ], which are risk factors for overall and CV mortality in PD patients. In addition, ESRD patients on dialysis for a number of years were associated with higher levels of alkaline phosphatase [ 35 , 36 ], which is traditionally a marker of high-turnover bone disease in ESRD patients but was recently found to be an independent predictor of adverse outcomes of peritonitis in PD patients [ 35 ].…”

The value of time-averaged serum high-sensitivity C-reactive protein in prediction of mortality and dropout in peritoneal dialysis patients

“…A similar finding was also reported by Ateş et al, showing variation in CRP levels during regular follow-up. 29 In the present study, the result of the multivariable Cox regression mode analysis revealed that the time-average serum HS-CRP level, instead of the baseline HS-CRP level, was an independent predictor of mortality and dropout in patients on PD. The ROC curve analysis also demonstrated that the mortality predictability of serum time-averaged HS-CRP level was superior to that of the serum baseline HS-CRP level.…”

“…This study demonstrated that 164 patients on PD (49.0%) had elevated time-averaged serum HS-CRP levels (>5 mg/L), similar to the Turkish report (47.4%). 29 In this study, patients in the high time-averaged serum HS-CRP tertile had a higher mortality and dropout rate during the 60-month follow-up. Correspondingly, the multivariate Cox regression analysis also demonstrated that the time-averaged serum HS-CRP level is superior to a single baseline measurement as an independent predictor of mortality and dropout.…”

“…The relationship between serum HS-CRP and subsequent mortality in patients on PD remains inconclusive ( Table 6 ). Although many studies have demonstrated that serum CRP is a powerful predictor of cardiovascular events and mortality, 29 , 35 – 38 some studies have reported that serum CRP is not associated with all-cause mortality significantly. 39 , 40 Moreover, membrane transporter status and residual urine have been reported as factors that affect serum CRP levels.…”

Association of baseline, longitudinal serum high-sensitive C-reactive protein and its change with mortality in peritoneal dialysis patients

“…Additionally, biological inter-individual and intra-individual variability of CRP levels in dialysis patients might be greater than the variability in health individuals [ 1 ]. Nevertheless, only a few small studies have assessed the consequences of longitudinal conventional CRP, but not hs-CRP, fluctuation on mortality among peritoneal dialysis (PD) patients [ 19 , 20 ].…”