['The prognostic role of C-reactive protein (CRP) in acute heart failure (HF) is not fully understood, and the impact of an infectious process in its risk-stratification power was not previously evaluated.', 'As CRP is an inflammatory marker, its prognostic value in acute HF is probably different in patients with and without concurrent infection.', 'We recruited patients admitted to our hospital due to acute HF from October 2006 to October 2007. All patients were given treatment at the discretion of the attending physician. Serum CRP was measured at discharge in 225 patients. We followed patients for 3 months after discharge to assess occurrence of all-cause death or readmission due to HF. Infection was defined according to diagnoses registered on the discharge record. Patients were classified according to CRP tertiles, in the entire sample and in groups according to infection occurrence.', ': An infectious condition occurred in 109 patients (first and second CRP tertiles: 8.8 and 27.4 mg/L, respectively). No infection was detected in 116 patients (5.0 and 12.3 mg/L, respectively). In the group with infection, CRP was not a good predictor of adverse outcome. In the noninfected group, the hazard ratio of those with CRP > 12.3 mg/L was 2.46 (95% confidence interval: 1.29-4.70) in comparison with those with lower CRP. Adjusted hazard ratio for ischemic heart disease and diabetes was 2.03 (95% confidence interval: 1.06-3.91).'] Does higher C-reactive protein predict worse prognosis in acute heart failure only in noninfected patients?