title: Predictive models of malignant transudative pleural effusions.
abstract: BACKGROUND
  There are no firm recommendations when cytology should be performed in pleural transudates, since some malignant pleural effusions (MPEs) behave biochemically as transudates. The objective was to assess when would be justified to perform cytology on pleural transudates.
  
  
  METHODS
  Consecutive patients with transudative pleural effusion (PE) were enrolled and divided in two groups: malignant and non-MPE. Logistic regression analysis was used to estimate the probability of malignancy. Two prognostic models were considered: (I) clinical-radiological variables; and (II) combination of clinical-radiological and analytical variables. Calibration and discrimination [receiver operating characteristics (ROC) curves and area under the curve (AUC)] were performed.
  
  
  RESULTS
  A total of 281 pleural transudates were included: 26 malignant and 255 non-malignant. The AUC obtained with Model 1 (left PE, radiological images compatible with malignancy, absence of dyspnea, and serosanguinous appearance of the fluid), and Model 2 (the variables of Model 1 plus CEA) were 0.973 and 0.995, respectively. Although no false negatives are found in Models 1 and 2 to probabilities of 11% and 14%, respectively, by applying bootstrapping techniques to not find false negatives in 95% of other possible samples would require lowering the cut-off points for the aforementioned probabilities to 3% (Model 1) and 4% (Model 2), respectively. The false positive results are 32 (Model 1) and 18 (Model 2), with no false negatives.
  
  
  CONCLUSIONS
  The applied models have a high discriminative ability to predict when a transudative PE may be of neoplastic origin, being superior to adding an analytical variable to the clinic-radiological variables.
authors.affiliation: Department of Pulmonology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain;; Interdisciplinary Research Group in Pulmonology, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain.
authors.forename: Lucía
authors.initials: L
authors.lastname: Ferreiro
authors.affiliation: Department of Clinical Epidemiology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain;; Department of Epidemiology of Common Diseases, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Gude
authors.affiliation: Department of Pulmonology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: María E
authors.initials: ME
authors.lastname: Toubes
authors.affiliation: Department of Pulmonology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Adriana
authors.initials: A
authors.lastname: Lama
authors.affiliation: Department of Pulmonology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Suárez-Antelo
authors.affiliation: Interdisciplinary Research Group in Pulmonology, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain;; Department of Clinical Analysis, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: San-José
authors.affiliation: Department of Pulmonology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain;; Interdisciplinary Research Group in Pulmonology, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: González-Barcala
authors.affiliation: Department of Pulmonology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain;; Interdisciplinary Research Group in Pulmonology, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Golpe
authors.affiliation: Department of Pulmonology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain;; Interdisciplinary Research Group in Pulmonology, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Álvarez-Dobaño
authors.affiliation: Department of Pulmonology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Rábade
authors.affiliation: Department of Pulmonology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: Rodríguez-Núñez
authors.affiliation: Statistics Unit, Department of Statistics and Operations Research, University of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Carla
authors.initials: C
authors.lastname: Díaz-Louzao
authors.affiliation: Department of Pulmonology, University Clinical Hospital of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Valdés
keywords: Pleural effusion (PE); cytology; malignant; thoracentesis