The Relationship Between C-reactive Protein(CRP)and N-terminal Brain Natriuretic Peptide(NT-proBNP) Values

Background:N-terminal brain natriuretic peptide has long been considered as the surrogate biomarker of heart failure in clinical works. However, it remains controversial if this parameter is still a valid option in patients with inflammations since a possible interaction between inflammatory response and natriuretic peptides. The objective of this study was to investigate the relationship between C-reactive protein, the labotory indicator of inflammation, and N-terminal brain natriuretic peptide levels.Methods:This research was performed on657inpatients who were hospitalized from January to June2014in the second affiliated hospital of Zhejiang University, including564patients with left ventricular ejection fraction (LVEF) more than50%measured by echocardiogram and93patients with that less than50%. We divided the patients into4groups with diferrent ranges of CRP concentrations. The relationship between CRP and NT-proBNP was then investigated. Result:657inpatients (male/female=445/212, mean age=67years) were enrolled in this rearch, including564patients with left ventricular ejection fraction (LVEF) more than50%measured by echocardiogram and93patients with that less than50%. According to CRP concentrations, patients were divided into4groups:Group1(CRP<10mg/L, n=21), Group2(10<CRP<50mg/L, n=236), Group3(50<CRP<100mg/L, n=191), Group4(CRP>100mg/L, n=209). NT-proBNP levels increase significantly with CRP elevation in patients whose LVEF were more than50%, while this trend was not significant in patients with preserved LVEF. NT-proBNP positively correlated with CRP regardless of the existence of cardiac dysfunction (r=0.507, P<0.0001; r=0.301, P<0.01, respectively).Conclusion:Our results indicate that NT-proBNP positively correlate with CRP, irrespective of LVEF level, providing further evidence to the hypothesis that there is an interaction between inflammatory response and NT-proBNP. Thus, interpretations on NT-proBNP levels should be more cautious as biomarker of heart failue in inflammatory patients.