title: Validated prediction model for the development of primary open-angle glaucoma in individuals with ocular hypertension.
abstract: OBJECTIVE
  To test the validity and generalizability of the Ocular Hypertension Treatment Study (OHTS) prediction model for the development of primary open-angle glaucoma (POAG) in a large independent sample of untreated ocular hypertensive individuals and to develop a quantitative calculator to estimate the 5-year risk that an individual with ocular hypertension will develop POAG.
  
  
  METHODS
  A prediction model was developed from the observation group of the OHTS and then tested on the placebo group of the European Glaucoma Prevention Study (EGPS) using a z statistic to compare hazard ratios, a c statistic for discrimination, and a calibration chi2 for systematic overestimation/underestimation of predicted risk. The 2 study samples were pooled to increase precision and generalizability of a 5-year predictive model for developing POAG.
  
  
  METHODS
  The OHTS observation group (n = 819; 6.6 years' median follow-up) and EGPS placebo group (n = 500; 4.8 years' median follow-up).
  
  
  METHODS
  Data were collected on demographic characteristics, medical history, ocular examination visual fields (VFs), and optic disc photographs.
  
  
  METHODS
  Development of reproducible VF abnormality or optic disc progression as determined by masked readers and attributed to POAG by a masked end point committee.
  
  
  RESULTS
  The same predictors for the development of POAG were identified independently in both the OHTS observation group and the EGPS placebo group-baseline age, intraocular pressure, central corneal thickness, vertical cup-to-disc ratio, and Humphrey VF pattern standard deviation. The pooled multivariate model for the development of POAG had good discrimination (c statistic, 0.74) and accurate estimation of POAG risk (calibration chi2, 7.05).
  
  
  CONCLUSIONS
  The OHTS prediction model was validated in the EGPS placebo group. A calculator to estimate the 5-year risk of developing POAG, based on the pooled OHTS-EGPS predictive model, has high precision and will be useful for clinicians and patients in deciding the frequency of tests and examinations during follow-up and advisability of initiating preventive treatment.
authors.affiliation: OHTS Coordinating Center, Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Box 8203, 660 South Euclid, St. Louis, MO 63110, USA. mae@vrcc.wustl.edu
authors.forename: Mae O
authors.initials: MO
authors.lastname: Gordon
authors.forename: Valter
authors.initials: V
authors.lastname: Torri
authors.forename: Stefano
authors.initials: S
authors.lastname: Miglior
authors.forename: Julia A
authors.initials: JA
authors.lastname: Beiser
authors.forename: Irene
authors.initials: I
authors.lastname: Floriani
authors.forename: J Philip
authors.initials: JP
authors.lastname: Miller
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Ingrid
authors.initials: I
authors.lastname: Adamsons
authors.forename: Davide
authors.initials: D
authors.lastname: Poli
authors.forename: Ralph B
authors.initials: RB
authors.lastname: D'Agostino
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kass
mesh_terms: D003315:Cornea / Q000473:pathology; D005260:Female; D005902:Glaucoma, Open-Angle / Q000209:etiology*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000150:complications*; D009898:Optic Disk / Q000473:pathology; D009901:Optic Nerve Diseases / Q000175:diagnosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D014786:Vision Disorders / Q000175:diagnosis; D014794:Visual Fields