title: External validation of a prediction model for penile prosthesis implantation for erectile dysfunction management.
abstract: BACKGROUND
  Penile prosthesis implantation (PPI) is the definitive surgical treatment for erectile dysfunction (ED), yet it is often delayed for a variety of reasons. From commercial and Medicare claims data, we previously developed a tool for determining a patient's likelihood of eventually receiving PPI. We validated this instrument's utility by comparing cohorts receiving surgical (PPI) versus non-surgical ED management at a single institution.
  
  
  METHODS
  The prediction model was based on a logistic regression incorporating claims data on demographics, comorbidities and ED therapy. A risk score is calculated from the model as the product of relative risks for the individual variables. The current validation was a retrospective analysis of ED patients seen at this institution from January to December 2012. Inclusion criteria included ED diagnosis and either first-time PPI or non-surgical treatment (controls). Risk scores for patients receiving PPI were compared to those of non-surgical controls.
  
  
  RESULTS
  We established a cohort of 60 PPI patients (mean age 54.4 ± 9.5) and compared them with 120 non-PPI patients (mean age 53.4 ± 11.2 years). The median score of the PPI cohort was 5.7 (IQR 2.8-9.9) versus the non-PPI cohort's 1.8 (IQR 0.9-5.5) (p < 0.0001). The area under the receiver operator characteristic curve for predicting eventual PPI was 0.72 (95% CI, 0.64-0.79) (p < 0.0001).
  
  
  CONCLUSIONS
  The prediction model risk-stratified men who ultimately underwent PPI compared to non-surgically managed controls. This external validation study suggests that the prediction model may be used on an individual patient basis to support a recommendation of PPI for managing ED.
authors.affiliation: The James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Uzoma A
authors.initials: UA
authors.lastname: Anele
authors.forename: Robert L
authors.initials: RL
authors.lastname: Segal
authors.forename: Brian V
authors.initials: BV
authors.lastname: Le
authors.forename: Arthur L
authors.initials: AL
authors.lastname: Burnett
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D016208:Databases, Factual; D019468:Disease Management; D007172:Erectile Dysfunction / Q000601:surgery*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D019935:Penile Implantation / Q000706:statistics & numerical data*; D010411:Penile Induration / Q000453:epidemiology; D011317:Priapism / Q000453:epidemiology; D011471:Prostatic Neoplasms / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D055815:Young Adult