title: Suboptimal prescribing in elderly outpatients: potentially harmful drug-drug and drug-disease combinations.
abstract: OBJECTIVE
  To assess the prevalence and correlates of potentially harmful drug-drug combinations and drug-disease combinations prescribed for elderly patients at outpatient settings.
  
  
  METHODS
  Retrospective analysis of the 1995-2000 National Ambulatory Medical Care Survey (NAMCS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS).
  
  
  METHODS
  Physician offices and hospital outpatient departments.
  
  
  METHODS
  Outpatient visits by patients aged 65 and older in the NAMCS and NHAMCS (n=70,203).
  
  
  METHODS
  Incidences of six drug-drug combinations and 50 drug-disease combinations that can place elderly patients at risk for adverse events according to expert consensus panels.
  
  
  RESULTS
  Overall, 0.74% (95% confidence interval (CI)=0.65-0.83) of visits with two or more prescriptions had at least one inappropriate drug-drug combination, and 2.58% (95% CI=2.44-2.72) of visits with at least one prescription had one or more inappropriate drug-disease combinations. Of visits with a prescription of warfarin, 6.60% (95% CI=5.46-7.74) were prescribed a drug with potentially harmful interaction. Of patients with benign prostatic hypertrophy, 4.06% (95% CI=3.06-5.06) had at least one of six drugs that should be avoided. The number of drugs prescribed is most predictive of inappropriate drug-drug and drug-disease combinations.
  
  
  CONCLUSIONS
  Potentially harmful drug-drug and drug-disease combinations occur in various degrees in outpatient care in the elderly population. Targeting combinations such as those involving warfarin that are high in prevalence and potential harm offers a practical approach to improving prescribing and patient safety.
authors.affiliation: Agency for Healthcare Research and Quality, Department of Health and Human Services, Rockville, Maryland 20850, USA. czhan@ahrq.gov <czhan@ahrq.gov>
authors.forename: Chunliu
authors.initials: C
authors.lastname: Zhan
authors.forename: Rosaly
authors.initials: R
authors.lastname: Correa-de-Araujo
authors.forename: Arlene S
authors.initials: AS
authors.lastname: Bierman
authors.forename: Judy
authors.initials: J
authors.lastname: Sangl
authors.forename: Marlene R
authors.initials: MR
authors.lastname: Miller
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Wickizer
authors.forename: Daniel
authors.initials: D
authors.lastname: Stryer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care; D000075202:Contraindications; D004347:Drug Interactions; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D005260:Female; D019538:Health Care Surveys; D006801:Humans; D008297:Male; D008508:Medication Errors / Q000706:statistics & numerical data*; D004364:Pharmaceutical Preparations; D015995:Prevalence; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology
chemical_list: D004364:Pharmaceutical Preparations