title: A novel structural risk index for primary spontaneous pneumothorax: Ankara Numune Risk Index.
abstract: BACKGROUND
  In this study, we aimed to reveal a novel risk index as a structural risk marker for primary spontanoeus pneumothorax using body mass index and chest height, structural risk factors for pneumothorax development.
  
  
  METHODS
  Records of 86 cases admitted between February 2014 and January 2015 with or without primary spontaneous pneumothorax were analysed retrospectively. The patients were allocated to two groups as Group I and Group II. The patients were evaluated with regard to age, gender, pneumothorax side, duration of hospital stay, treatment type, recurrence, chest height and transverse diameter on posteroanterior chest graphy and body mass index. Body mass index ratio per cm of chest height was calculated by dividing body mass index with chest height. We named this risk index ratio which is defined first as 'Ankara Numune Risk Index'. Diagnostic value of Ankara Numune Risk Index value for prediction of primary spontaneous pneumothorax development was analysed with Receiver Operating Characteristics curver.
  
  
  RESULTS
  Of 86 patients, 69 (80.2%) were male and 17 (19.8%) were female. Each group was composed of 43 (50%) patients. When Receiver Operating Characteristics curve analysis was done for optimal limit value 0.74 of Ankara Numune Risk Index determined for prediction of pneumothorax development risk, area under the curve was 0.925 (95% Cl, 0.872-0.977, p < 0.001).
  
  
  CONCLUSIONS
  Ankara Numune Risk Index is one of the structural risk factors for prediction of primary spontaneous pneumothorax development however it is insufficient for determining recurrence.
authors.affiliation: Department of Thoracic Surgery, Ankara Numune Research and Training Hospital, Ankara, Turkey. Electronic address: y.akkas@yahoo.com.
authors.forename: Yucel
authors.initials: Y
authors.lastname: Akkas
authors.affiliation: Department of Thoracic Surgery, Ankara Numune Research and Training Hospital, Ankara, Turkey.
authors.forename: Neslihan Gulay
authors.initials: NG
authors.lastname: Peri
authors.affiliation: Department of Thoracic Surgery, Ankara Numune Research and Training Hospital, Ankara, Turkey.
authors.forename: Bulent
authors.initials: B
authors.lastname: Kocer
authors.affiliation: Department of Thoracic Surgery, Ufuk University Faculty of Medicine, Ankara, Turkey.
authors.forename: Tevfik
authors.initials: T
authors.lastname: Kaplan
authors.affiliation: Department of Statistics, Ufuk University Faculty of Arts and Science, Ankara, Turkey.
authors.forename: Aslihan
authors.initials: A
authors.lastname: Alhan
mesh_terms: D000293:Adolescent; D000328:Adult; D001827:Body Height; D015992:Body Mass Index; D003661:Decision Support Techniques; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D011030:Pneumothorax / Q000175:diagnosis* / Q000209:etiology; D012372:ROC Curve; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Ankara Numune Risk Index; body mass index; chest height; primary spontaneous pneumothorax; structural factors