C-reactive protein and procalcitonin as markers of mortality in hemodialysis patients: A 2-year prospective study

Objective: We have previously shown in a transversal study that PCT combined to CRP is associated to an altered nutritional status in hemodialysis patients. In a 2-year prospective study, we have assessed the relationship between markers of inflammation or nutrition and mortality. Design: Two-year prospective study, in 61 patients dialyzed in our unit (29 M/32 F, age 63 15 years, on dialysis for 76 94 months, 12 hrs/wk, on high-flux (HF) membrane for 25 patients and low-flux (LF) for 36 patients, without reuse). Kt/V was 1.53 +/- 0.30. Setting: Hospital-based dialysis unit. Main Outcome Measure: CRP, PCT, ferritin, albumin, and prealbumin, were measured in 04/99 (TO) and every 6 months thereafter. Interleukin-6 (11-6) and fibrinogen were measured at the start of study. The outcome and the causes of death of patients were noted in 58 patients, 3 patients were lost of follow-up. Results: The mortality (24 deaths) was 42% at 2 years in this hospital based unit. The main causes of mortality were cardiovascular diseases (71%) and infection (17%). Patients were classified according to their CRP (CRP+ if CRP greater than or equal to 5 mg/L; n = 40), and PCT values (PCT + if PCT greater than or equal to 0.5 ng/mL; n = 25). IL6 level was 10 pg/mL for 95% of the patients. Mortality was higher in the CRP+ group (Kaplan-Meier test P less than or equal to .01) but not in the PCT or IL6 positive patients. All patients of the CRP+ group at TO remained CRP+. Only 56% of patients of PCT+ remained positive at 6 months. When patients were grouped according to CRP quartile the difference on survival remained significant (P = .03), patients who were classified in the third and fourth quartile (upper than 9.9 mg/L), exhibited a higher rate of mortality than the lower quartile. The concomitant presence of a high level of PCT and CRP was associated with a worsened nutritional status at TO but PCT level had no influence on 2-year mortality. Conclusion: In this 2-year prospective study in a hospital-based cohort of high-risk hernodialysis patients, elevated CRP, but not raised PCT, was associated with increased mortality. Inflammation remained present throughout a 2-year follow-up in patients with an initial CRP higher than 5 mg/L. An upper value of CRP above 9.9 mg/L is independly predictive of mortality, mainly from cardiovascular causes. The association of high PCT and CRP was no more predictive of mortality than high CRP. (C) 2003 by the National Kidney Foundation, Inc.