Combined efficacy of C-reactive protein and red blood cell distribution width in prognosis of patients with culture-negative infective endocarditis

OBJECTIVE: To evaluate the combined effect of C-reactive protein (CRP) and red blood cell distribution width (RDW) on the prediction of in-hospital and long-term poor outcomes in patients with blood culture-negative infective endocarditis (BCNE). RESULTS: Patients with high CRP and high RDW has the highest incidence of in-hospital death (2.3% vs. 7.8% vs. 5.6% vs. 17.5%, P < 0.001). CRP > 17.8 mg/L (odds ratio [OR]=2.41, 95% confidence interval [CI], 1.06–5.51, P = 0.037), RDW >16.3 (OR = 2.29, 95% CI, 1.10–4.77, P = 0.027), and these two values in combination (OR = 3.15, 95% CI, 1.46–6.78, P=0.003) were independently associated with in-hospital death. Patients with RDW > 16.3 had higher long-term mortality (P = 0.003), while no significant correlation was observed for CRP (P = 0.151). MATERIALS AND METHODS: In total, 572 participants with BCNE were consecutively enrolled. They were classified into four groups based on the optimal CRP and RDW cut-off values (which were determined using a receiver operating characteristic analysis): low CRP and low RDW (n = 216), high CRP and low RDW (n = 129), low CRP and high RDW (n = 107), and high CRP and high RDW (n = 120). CONCLUSIONS: Increased CRP and RDW, especially in combination, are independently associated with in-hospital death in BCNE. RDW, but not CRP, has long-term prognostic value.