title: Predicting mortality over different time horizons: which data elements are needed?
abstract: Electronic health records (EHRs) are a resource for "big data" analytics, containing a variety of data elements. We investigate how different categories of information contribute to prediction of mortality over different time horizons among patients undergoing hemodialysis treatment.
  
  
  
  We derived prediction models for mortality over 7 time horizons using EHR data on older patients from a national chain of dialysis clinics linked with administrative data using LASSO (least absolute shrinkage and selection operator) regression. We assessed how different categories of information relate to risk assessment and compared discrete models to time-to-event models.
  
  
  
  The best predictors used all the available data (c-statistic ranged from 0.72-0.76), with stronger models in the near term. While different variable groups showed different utility, exclusion of any particular group did not lead to a meaningfully different risk assessment. Discrete time models performed better than time-to-event models.
  
  
  
  Different variable groups were predictive over different time horizons, with vital signs most predictive for near-term mortality and demographic and comorbidities more important in long-term mortality.
authors.affiliation: Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina ben.goldstein@duke.edu.|Center for Predictive Medicine, Duke Clinical Research Institute, Durham, North Carolina.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Goldstein
authors.affiliation: Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina.|Center for Predictive Medicine, Duke Clinical Research Institute, Durham, North Carolina.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pencina
authors.affiliation: Division of Nephrology, Stanford University School of Medicine, Palo Alto, California.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Montez-Rath
authors.affiliation: Section of Nephrology, Baylor College of Medicine, Houston, Texas.
authors.forename: Wolfgang C
authors.initials: WC
authors.lastname: Winkelmayer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D057225:Data Mining; D057286:Electronic Health Records; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009026:Mortality; D011379:Prognosis; D006435:Renal Dialysis; D013995:Time
keywords: ESRD; Electronic Health Records; hemodialysis; predictive modeling