title: External validation of a nomogram that predicts the pathological diagnosis of thyroid nodules in a Chinese population.
abstract: BACKGROUND
  Nomograms are statistical predictive models that can provide the probability of a clinical event. Nomograms have better performance for the estimation of individual risks because of their increased accuracy and objectivity relative to physicians' personal experiences. Recently, a nomogram for predicting the likelihood that a thyroid nodule is malignant was introduced by Nixon. The aim of this study was to determine whether Nixon's nomogram can be validated in a Chinese population.
  
  
  METHODS
  All consecutive patients with thyroid nodules who underwent surgery between January and June 2012 in our hospital were enrolled to validate Nixon's nomogram. Univariate and multivariate analyses were used to identify the risk factors for thyroid carcinoma. Discrimination and calibration were employed to evaluate the performance of Nixon's model in our population.
  
  
  RESULTS
  A total of 348 consecutive patients with 409 thyroid nodules were enrolled. Thyroid ultrasonographic characteristics, including shape, echo texture, calcification, margins, vascularity and number (solitary vs. multiple nodules), were associated with malignance in the multivariate analysis. The discrimination of all nodules group, the group with a low risk of malignancy (predictive proportion <50%) and the group with a high risk of malignancy (predictive proportion ≥50%) using Nixon's nomogram was satisfactory, and the area under the receiver operating characteristic curve of the three groups were 0.87, 0.75 and 0.72, respectively. However, the calibration was significant (p = 0.55) only in the high-risk group.
  
  
  CONCLUSIONS
  Nixon's nomogram is a valuable predictive model for the Chinese population and has been externally validated. It has good performance for patients with a high risk of malignancy and may be more suitable for use with these patients in China.
authors.affiliation: Department of Vascular and Thyroid Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, PR China.
authors.forename: Ridong
authors.initials: R
authors.lastname: Wu
authors.forename: Liling
authors.initials: L
authors.lastname: Zhu
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.forename: Qing
authors.initials: Q
authors.lastname: Tang
authors.forename: Fushun
authors.initials: F
authors.lastname: Pan
authors.forename: Weibin
authors.initials: W
authors.lastname: Wu
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Chen
authors.initials: C
authors.lastname: Yao
authors.forename: Shenming
authors.initials: S
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D002138:Calibration; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D049451:Nomograms; D012372:ROC Curve; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000473:pathology*; D055815:Young Adult