Validation of a 5-Year Prognostic Model for Parkinson's Disease.

Background: A simple prognostic model was previously developed to predict the probability of recently-diagnosed patients reaching negative outcomes (postural instability, dementia or death) in a 5-year period.

Objectives: To validate this model in an independent cohort and establish utility at later time points.

Methods: Validation was performed using data collected in an incident cohort at baseline, 2 and 4 years. Predicted negative outcome probabilities were compared to actual 5-year outcomes.

Results: The model, based on age, MDS-UPDRS axial score and 60-second animal fluency, predicted poor 5-year outcome when applied at baseline, (area under the curve (AUC) 0.80), 2 years (AUC 0.82) and 4 years (AUC 0.71). Power calculations showed that selecting a subgroup with prognostic score >0.5 reduced the sample size required for a disease-modifying trial.

Conclusions: This 5-year prognostic model has good accuracy when employed up to 4 years from diagnosis and may help stratification for disease-modifying trials.