title: YKL-40, CCL18 and SP-D predict mortality in patients hospitalized with community-acquired pneumonia.
abstract: The aim of this study was to investigate the prognostic value of four biomarkers, YKL-40, chemokine (C-C motif) ligand 18 (CCL18), surfactant protein-D (SP-D) and CA 15-3, in patients admitted with community-acquired pneumonia (CAP). These markers have been studied extensively in chronic pulmonary disease, but in acute pulmonary disease their prognostic value is unknown.
  
  
  
  A total of 289 adult patients who were hospitalized with CAP and participated in a randomized controlled trial were enrolled. Biomarker levels were measured on the day of admission. Intensive care unit admission, 30-day, 1-year and long-term mortality (median follow-up of 5.4 years, interquartile range (IQR): 4.7-6.1) were recorded as outcomes.
  
  
  
  Median YKL-40 and CCL18 levels were significantly higher and levels of SP-D were significantly lower in CAP patients compared to healthy controls. Significantly higher YKL-40, CCL18 and SP-D levels were found in patients classified in pneumonia severity index classes 4-5 and with a CURB-65 score ≥2 compared to patients with less severe pneumonia. Furthermore, these three markers were significant predictors for long-term mortality in multivariate analysis and compared with C-reactive protein and procalcitonin level on admission, area under the curves were higher for 30-day, 1-year and long-term mortality. CA 15-3 levels were less predictive.
  
  
  
  YKL-40, CCL18 and SP-D levels were higher in patients with more severe pneumonia, possibly reflecting the extent of pulmonary inflammation. Of these, YKL-40 most significantly predicts mortality for CAP.
authors: Department of Internal Medicine, St Antonius Hospital, Nieuwegein, The Netherlands.
authors: Simone M C
authors: SM
authors: Spoorenberg
authors: Department of Internal Medicine, St Antonius Hospital, Nieuwegein, The Netherlands.
authors: Stefan M T
authors: SM
authors: Vestjens
authors: Department of Medical Microbiology and Immunology, St Antonius Hospital, Nieuwegein, The Netherlands.|Department of Sciences, University College Roosevelt, Middelburg, The Netherlands.
authors: Ger T
authors: GT
authors: Rijkers
authors: Department of Medical Microbiology and Immunology, St Antonius Hospital, Nieuwegein, The Netherlands.
authors: Bob
authors: B
authors: Meek
authors: Department of Pulmonology, St Antonius Hospital, Nieuwegein, The Netherlands.|Division of Heart and Lungs, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors: Coline H M
authors: CH
authors: van Moorsel
authors: Department of Pulmonology, St Antonius Hospital, Nieuwegein, The Netherlands.|Division of Heart and Lungs, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors: Jan C
authors: JC
authors: Grutters
authors: Department of Internal Medicine, St Antonius Hospital, Nieuwegein, The Netherlands.
authors: Willem Jan W
authors: WJ
authors: Bos
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein; D002116:Calcitonin / Q000097:blood; D019742:Chemokines, CC / Q000097:blood*; D000071451:Chitinase-3-Like Protein 1 / Q000097:blood*; D017714:Community-Acquired Infections / Q000097:blood* / Q000401:mortality; D005260:Female; D006760:Hospitalization; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D018396:Mucin-1 / Q000097:blood*; D011014:Pneumonia / Q000097:blood* / Q000401:mortality; D011379:Prognosis; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood*; D012372:ROC Curve; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; C111792:CCL18 protein, human; D019742:Chemokines, CC; D000071451:Chitinase-3-Like Protein 1; D018396:Mucin-1; D037663:Pulmonary Surfactant-Associated Protein D; D002116:Calcitonin; D002097:C-Reactive Protein
keywords: 
  YKL-40 protein, human; biomarkers; chemokine (C-C motif) ligand 18 protein, human; mortality; pneumonia