title: Variation over time in the association between polypharmacy and mortality in the older population.
abstract: BACKGROUND
  In the older population, multimorbidity is common and 'best practice' may invite the prescription of multiple medications.
  
  
  OBJECTIVE
  To examine the association between polypharmacy, defined as the concurrent use of five or more prescription or nonprescription medications, and mortality in 12 423 participants aged ≥65 years representative of the older population of England and Wales.
  
  
  METHODS
  Data on self-reported medication use, disability and health conditions were collected at baseline in 1991-3. The cohort was followed for up to 18 years with full mortality notification. Cox proportional hazards regression adjusted for age, baseline institutionalization, smoking, disability and health conditions was used to investigate polypharmacy and mortality, stratified by sex. Various methods for modelling the time-varying effect of polypharmacy are presented.
  
  
  RESULTS
  A strong independent association between polypharmacy and mortality existed in the short-term (first 2 years) for both men and women. This association remained, although attenuated, in the medium-long term (2-18 years of follow-up) for women, but became non-significant in the longer term for men.
  
  
  CONCLUSIONS
  It remains unclear whether polypharmacy is a marker for poor health or is an independent risk factor for mortality. However, polypharmacy strongly predicts adverse outcomes, and multiple medication use should therefore be carefully monitored in the older population.
authors: Institute of Public Health, University of Cambridge, Cambridge, UK. richarkj@tcd.ie
authors: Kathryn
authors: K
authors: Richardson
authors: Alexandrine
authors: A
authors: Ananou
authors: Louise
authors: L
authors: Lafortune
authors: Carol
authors: C
authors: Brayne
authors: Fiona E
authors: FE
authors: Matthews
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D004739:England; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D009026:Mortality; D019338:Polypharmacy; D016016:Proportional Hazards Models; D011795:Surveys and Questionnaires; D013997:Time Factors; D014852:Wales