title: Validation of a prediction algorithm for progression to advanced macular degeneration subtypes.
abstract: OBJECTIVE
  Risk score models predicting the progression of age-related macular degeneration (AMD) to its advanced forms may be useful for targeting high-risk individuals for lifestyle changes that reduce risk for AMD progression, helping with differential diagnosis of AMD and its subtypes, identifying high-risk subjects for participation in clinical trials, and selecting appropriate therapies.
  
  
  OBJECTIVE
  To develop and validate a predictive model for progression to advanced stages of AMD in 2 independent cohorts. DESIGN Participants in a validation cohort and an independent derivation population were classified into 5 stages of AMD based on ocular examination and fundus photographs at baseline. Progression was defined as either eye progressing from stage 1, 2, or 3 to either stage 4 or stage 5 at any follow-up visit to the end of the study. Cox proportional hazards models were used for progression analyses. Covariates included demographic and environmental factors, 6 variants in 5 genes, and baseline AMD grades in both eyes. The algorithm developed with the derivation sample was assessed for calibration and discrimination in the validation data set.
  
  
  METHODS
  Clinic populations and referrals.
  
  
  METHODS
  The derivation population comprised 2914 subjects with 809 progressors. The independent validation cohort comprised 980 individuals with no, early, or intermediate AMD in at least one eye at baseline, of whom 294 progressed to advanced stages of geographic atrophy or neovascular disease.
  
  
  METHODS
  Progression to advanced AMD. RESULTS For the model with all nongenetic and genetic factors, the respective C statistics for progression to advanced AMD in the derivation and validation samples were 0.858 and 0.750 at 5 years and 0.884 and 0.809 at 10 years, and models also discriminated risk for progression to geographic atrophy and neovascular disease separately. For unilateral or bilateral intermediate AMD, 5-year cumulative incidence rates of progression to advanced AMD were 10% with the low-risk score and 50% with the high-risk score; for unilateral advanced disease, the progression rates were 22% and 80% for the fellow eye.
  
  
  CONCLUSIONS
  The risk prediction model was validated in an independent study of progression from no, early, or intermediate stages to advanced subtypes of AMD and will be useful for research, clinical trials, and personalized medicine.
authors: Ophthalmic Epidemiology and Genetics Service, New England Eye Center, Tufts Medical Center, Boston, MA 02111, USA. jseddon@tuftsmedicalcenter.org
authors: Johanna M
authors: JM
authors: Seddon
authors: Robyn
authors: R
authors: Reynolds
authors: Yi
authors: Y
authors: Yu
authors: Bernard
authors: B
authors: Rosner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D019540:Area Under Curve; D003175:Complement C2 / Q000235:genetics; D003176:Complement C3 / Q000235:genetics; D011415:Complement Factor B / Q000235:genetics; D017242:Complement Factor H / Q000235:genetics; D018450:Disease Progression; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D060005:Genotyping Techniques; D000074289:High-Temperature Requirement A Serine Peptidase 1; D006801:Humans; D008268:Macular Degeneration / Q000145:classification / Q000175:diagnosis* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011506:Proteins / Q000235:genetics; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012697:Serine Endopeptidases / Q000235:genetics; D014792:Visual Acuity / Q000502:physiology
chemical_list: C514392:ARMS2 protein, human; C493495:CFH protein, human; D003175:Complement C2; D003176:Complement C3; D011506:Proteins; D017242:Complement Factor H; D000074289:High-Temperature Requirement A Serine Peptidase 1; C474012:HTRA1 protein, human; D012697:Serine Endopeptidases; D011415:Complement Factor B