The Impact of Occasional vs Persistent Inflammation on the Survival of HD Patients

Abstract

An elevated CRP level is associated with increased mortality in dialysis pts but the impact of occasional vs persistent inflammation is not known. Objective: To assess the influence on survival of fluctuating vs persistent inflammation in HD pts. Methods: We prospectively (bimonthly) analysed: CRP, S-Alb and fibrinogen in 180 HD pts (49 ± 14 y, 54 % M, 9% DM) with a mean follow up of 21 months. The nutritional status was evaluated by SGA. According to the median of 4 consecutive measurements of CRP and by using the receiver operating characteristics to determine the criteria for inflammation, the patients were allocated into 3 groups: Group 1(n = 64), non-inflamed (CRP < 4.8 mg/l); Group 2 (n = 67), fluctuating levels of CRP (CRP 4.8–10.3 mg/l); and Group 3 (n = 49), persistently inflamed (CRP > 10.3 mg/l). Cox proportional hazard analysis was used to assess independent predictors of survival, and mortality was analyzed by Kaplan Meier analysis. Results: The median baseline CRP was 3.6 (range 3.2 to 82) mg/l. The mean ± SD concentration of fibrinogen was 42 ± 11, 50 ± 12 and 57 ± 12 g/l (p < 0.001), and of S-Alb, 35 ± 3, 35 ± 3 and 34 ± 4 g/l (p = 0.3) for Groups 1, 2 and 3, respectively. The incidence of malnutrition was 57%, 59% and 72% in Groups 1, 2 and 3, respectively (p = 0.22). The survival rate (Kaplan Meier) was significantly different among the groups (chi-square 11.65; p = 0.003). Whereas the survival in Group 3 was only 70% after 21 months, it was similar in Group 1 (91%) and Group 2 (90%). A single measurement of CRP, and age, S-Alb and malnutrition were independent predictors of mortality (Cox analysis). Conclusion: An occasional elevation of CRP in HD pts appears to be relatively benign and the mortality predictive effect of a single high CRP level is therefore mainly related to its association with a persistent increase in CRP which on the other hand is a strong predictor of outcome.