title: Inter-practice variation in polypharmacy prevalence amongst older patients in primary care.
abstract: Complex medication management in older people with multiple chronic conditions can introduce practice variation in polypharmacy prevalence. This study aimed to determine the inter-practice variation in polypharmacy prevalence and examine how this variation was influenced by patient and practice characteristics.
  
  
  
  This cohort study included 45,731 patients aged 55 years and older with at least one prescribed medication from 126 general practices that participated in NIVEL Primary Care Database in the Netherlands. Medication dispensing data of the year 2012 were used to determine polypharmacy. Polypharmacy was defined as the chronic and simultaneous use of at least five different medications. Multilevel logistic regression models were constructed to quantify the polypharmacy prevalence variation between practices. Patient characteristics (age, gender, socioeconomic status, number, and type of chronic conditions) and practice characteristics (practice location and practice population) were added to the models.
  
  
  
  After accounting for differences in patient and practice characteristics, polypharmacy rates varied with a factor of 2.4 between practices (from 12.4% to 30.1%) and an overall mean of 19.8%. Age and type of conditions were highly positively associated with polypharmacy, and to a lesser extent a lower socioeconomic status.
  
  
  
  Considerable variation in polypharmacy rates existed between general practices, even after accounting for patient and practice characteristics, which suggests that there is not much agreement concerning medication management in this complex patient group. Initiatives that could reduce inappropriate heterogeneity in medication management can add value to the care delivered to these patients. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands.|Radboud University Medical Center, Radboud Institute for Health Sciences, IQ Healthcare, Nijmegen, The Netherlands.
authors.forename: Judith
authors.initials: J
authors.lastname: Sinnige
authors.affiliation: Radboud University Medical Center, Radboud Institute for Health Sciences, IQ Healthcare, Nijmegen, The Netherlands.
authors.forename: Jozé C
authors.initials: JC
authors.lastname: Braspenning
authors.affiliation: NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands.|Department of General Practice and Elderly Care Medicine, EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: François G
authors.initials: FG
authors.lastname: Schellevis
authors.affiliation: NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands.
authors.forename: Karin
authors.initials: K
authors.lastname: Hek
authors.affiliation: NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands.
authors.forename: Irina
authors.initials: I
authors.lastname: Stirbu
authors.affiliation: Radboud University Medical Center, Radboud Institute for Health Sciences, IQ Healthcare, Nijmegen, The Netherlands.
authors.forename: Gert P
authors.initials: GP
authors.lastname: Westert
authors.affiliation: NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands.
authors.forename: Joke C
authors.initials: JC
authors.lastname: Korevaar
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D057970:Inappropriate Prescribing / Q000706:statistics & numerical data*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D019338:Polypharmacy; D010818:Practice Patterns, Physicians' / Q000592:standards / Q000706:statistics & numerical data*; D055553:Prescription Drugs / Q000008:administration & dosage*; D015995:Prevalence; D011320:Primary Health Care / Q000458:organization & administration / Q000706:statistics & numerical data*; D012959:Socioeconomic Factors
chemical_list: D055553:Prescription Drugs
keywords: aged; drug utilization; medical practice variation; pharmacoepidemiology; polypharmacy; primary care