title: Prognostic model for HIV-1 disease progression in patients starting antiretroviral therapy was validated using independent data.
abstract: OBJECTIVE
  The Antiretroviral Therapy (ART) Cohort Collaboration published models predicting progression to AIDS or death (the complement of AIDS-free survival) and death (the complement of absolute survival). The objective is to validate the model on independent data from CASCADE.
  
  
  METHODS
  Discrimination was assessed using concordance statistics, and calibration was examined by comparing predicted survival curves with the corresponding Kaplan-Meier estimates. Accuracy was assessed by comparing predicted percentage probability of survival with the Kaplan-Meier estimate at yearly intervals after start of therapy.
  
  
  RESULTS
  There was little loss of model discrimination when applying the model to CASCADE. Overall predicted calibration curves agreed with Kaplan-Meier survival curves. Predicted probabilities of AIDS or death at 3 years after starting HAART ranged from 4.3% in the low-risk group to 20.5% in high-risk patients, with corresponding Kaplan-Meier estimates ranging from 4.0% to 18.3%; for death predictions, the probabilities ranged from 1.2% to 7.3% and estimates from 1.1% to 8.6%.
  
  
  CONCLUSIONS
  The predictions from the model agree with observed outcomes in CASCADE to within the 95% upper and lower Kaplan-Meier estimates. The prognostic model appears to be accurate in terms of discrimination and calibration, giving reliable and transportable predictions up to 3 years after the start of HAART.
authors.affiliation: Antiretroviral Therapy (ART) Cohort Collaboration; Department of Social Medicine, University of Bristol, Bristol BS8 2PR, UK. m.t.may@bristol.ac.uk
authors.forename: Margaret
authors.initials: M
authors.lastname: May
authors.forename: Kholoud
authors.initials: K
authors.lastname: Porter
authors.forename: Jonathan A C
authors.initials: JA
authors.lastname: Sterne
authors.forename: Patrick
authors.initials: P
authors.lastname: Royston
authors.forename: Matthias
authors.initials: M
authors.lastname: Egger
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D018450:Disease Progression; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011379:Prognosis; D012367:RNA, Viral / Q000097:blood; D012307:Risk Factors; D016019:Survival Analysis; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: D012367:RNA, Viral