title: The impact of admission neutrophil-to-platelet ratio on in-hospital and long-term mortality in patients with infective endocarditis.
abstract: BACKGROUND
  Infective endocarditis (IE) is associated with increased neutrophil and reduced platelet counts. We assessed the relationship between the neutrophil-to-platelet ratio (NPR) on admission and adverse outcomes in patients with IE.
  
  
  METHODS
  Patients diagnosed with IE between January 2009 and July 2015 (n=1293) were enrolled, and 1046 were finally entered into the study. Study subjects were categorized into four groups according to NPR quartiles: Q1<18.9 (n=260); Q2: 18.9-27.7 (n=258); Q3: 27.7-43.3 (n=266); and Q4>43.3 (n=262). Cox proportional hazards regression was performed to identify risk factors for long-term mortality; the optimal cut-off was evaluated by receiver operating characteristic curves.
  
  
  RESULTS
  Risk of in-hospital death increased progressively with NPR group number (1.9 vs. 5.0 vs. 9.8 vs. 14.1%, p<0.001). The follow-up period was a median of 28.8 months, during which 144 subjects (14.3%) died. Long-term mortality increased from the lowest to the highest NPR quartiles (7.6, 11.8, 17.4, and 26.2%, respectively, p<0.001). Multivariate Cox proportional hazard analysis revealed that lgNPR (HR=2.22) was an independent predictor of long-term mortality. Kaplan-Meier survival curves showed that subjects in Q4 had an increased long-term mortality compared with the other groups.
  
  
  CONCLUSIONS
  Increased NPR was associated with in-hospital and long-term mortality in patients with IE. As a simple and inexpensive index, NPR may be a useful and rapid screening tool to identify IE patients at high risk of mortality.
authors.affiliation: Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, P.R.
authors.forename: Xue-Biao
authors.initials: XB
authors.lastname: Wei
authors.affiliation: Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, P.R.
authors.forename: Yuan-Hui
authors.initials: YH
authors.lastname: Liu
authors.affiliation: Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, P.R.
authors.forename: Peng-Cheng
authors.initials: PC
authors.lastname: He
authors.affiliation: Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, P.R.
authors.forename: Dan-Qing
authors.initials: DQ
authors.lastname: Yu
authors.affiliation: Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, P.R.
authors.forename: Ning
authors.initials: N
authors.lastname: Tan
authors.affiliation: Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, P.R.
authors.forename: Ying-Ling
authors.initials: YL
authors.lastname: Zhou
authors.affiliation: Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, P.R.
authors.forename: Ji-Yan
authors.initials: JY
authors.lastname: Chen
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000166:cytology*; D004696:Endocarditis / Q000097:blood* / Q000401:mortality* / Q000628:therapy; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D009504:Neutrophils / Q000166:cytology*; D010343:Patient Admission; D011237:Predictive Value of Tests; D013997:Time Factors
keywords: infective endocarditis; neutrophil; outcome; platelet