Background: A single elevated C-reactive protein (CRP) value predicts mortality in haemodialysis (HD) patients, but the relative importance of repeated vs occasional positive systemic inflammatory response findings is not known.
Methods: To assess the influence on survival of occasional inflammation, CRP, serum albumin (S-Alb) and fibrinogen were analysed bimonthly in 180 HD patients (54% male, 49+/-14 years). Clinically significant inflammation was defined as CRP >5.1 mg/l, based on the receiver operating characteristics curve for CRP as predictor of death. Based on four consecutive measurements of CRP, patients were assigned into three groups: group 1 (n = 74; 41%), no inflammation (CRP < or = 5.1 mg/l in all measurements); group 2 (n = 65; 36%), occasional inflammation (1-3 measurements of CRP > 5.1 mg/l); and group 3 (n = 41; 23%), persistent inflammation (all measurements of CRP >5.1 mg/l). The nutritional status was evaluated by subjective global assessment (SGA) and body mass index (BMI), and the survival (21 months of follow-up) by Kaplan-Meier curve and Cox model.
Results: The median and range of CRP values (mg/l) for group 1, 2 and 3 were: 3.2 (3.2-5.1), 3.6 (3.2-54.9) and 13.8 (5.2-82), respectively (P<0.001), whereas the prevalence of malnutrition, assessed by SGA and BMI, did not differ significantly between the groups. The survival rate by Kaplan-Meier analysis was significantly different among the groups (chi2 = 12.34; P = 0.0004). Patients in group 3 showed the highest mortality (34%; P = 0.001), compared with group 1 (8%) and group 2 (14%; P = 0.01), respectively, whereas there was no significant difference in mortality between groups 1 and 2. Age, CRP, S-Alb level and SGA were independent predictors of mortality.
Conclusion: The patients with a persistent elevation of CRP had a higher mortality rate than the patients with occasional CRP elevation. Thus, persistent, rather than occasional, inflammation is an important predictor of death in HD patients.