title: MR-pro-atrial natriuretic peptide (MR-proANP) predicts short- and long-term outcomes in respiratory tract infections: a prospective validation study.
abstract: BACKGROUND
  Previous research found precursor levels of the atrial natriuretic peptide (MR-proANP) to be promising prognostic markers. This study aims to validate these findings and describe patterns of MR-proANP in a large cohort of patients with lower respiratory tract infections.
  
  
  METHODS
  We conducted a multicenter prospective cohort study, and measured MR-proANP in patients with lower respiratory tract infections on admission, and days 3, 5 and 7. The prognostic value of MR-proANP for predicting 30-day and 180-day mortalities was evaluated. We stratified MR-proANP levels a priori into quartiles, and compared it with severity of illness using the pneumonia severity index.
  
  
  RESULTS
  A total of 1359 patients, including 925 with community-acquired pneumonia, were enrolled. The mortality risk at days 30 and 180 significantly increased with increasing MR-proANP quartiles (<84 pmol/L, 84-158 pmol/L, >158-311 pmol/L, and >311 pmol/L). This was true for low-risk, as well as high-risk subjects (pneumonia severity index classes I-III and IV-V). In Kaplan-Meier survival curves, MR-proANP quartiles significantly separated survivors from non-survivors in the overall cohort (p log-rank<0.001), and in low-risk (p log-rank<0.03) and high-risk (p log-rank=0.007) pneumonia severity index patients at day 30. In multivariate logistic regression analysis, MR-proANP was an independent risk factor for 30-day and 180-day mortalities (odds ratio per unit increase of log transformation MR-proANP level: 5.58, 95%CI 1.97-15.82 and 5.08, 95%CI 2.44-10.60).
  
  
  CONCLUSIONS
  This study confirms the high prognostic performance of MR-proANP for short- and long-term mortality, particularly its high negative predictive value, in lower respiratory tract infections and community-acquired pneumonia, thereby complementing clinical risk assessment with the pneumonia severity index.
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Diabetes and Clinical Nutrition, University Hospital Basel, Switzerland.
authors.forename: Miriam
authors.initials: M
authors.lastname: Vazquez
authors.forename: Katharina
authors.initials: K
authors.lastname: Jockers
authors.forename: Mirjam
authors.initials: M
authors.lastname: Christ-Crain
authors.forename: Werner
authors.initials: W
authors.lastname: Zimmerli
authors.forename: Beat
authors.initials: B
authors.lastname: Müller
authors.forename: Philipp
authors.initials: P
authors.lastname: Schuetz
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D009320:Atrial Natriuretic Factor / Q000097:blood*; D017714:Community-Acquired Infections / Q000097:blood / Q000175:diagnosis / Q000401:mortality; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011014:Pneumonia / Q000097:blood* / Q000175:diagnosis / Q000401:mortality*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D012141:Respiratory Tract Infections / Q000097:blood / Q000175:diagnosis / Q000401:mortality; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: C552580:midregional pro-atrial natriuretic peptide, human; D009320:Atrial Natriuretic Factor