title: Defining polypharmacy in the elderly: a systematic review protocol.
abstract: BACKGROUND
  Ageing--along with its associated physiological and pathological changes--places individuals at a higher risk of multimorbidity and treatment-related complications. Today, polypharmacy, a common and important problem related to drug use, occurs subsequent to this multimorbidity in the elderly in all populations. In recent decades, several scientific investigations have studied polypharmacy and its correlates, using different approaches and definitions, and their results have been inconclusive. Differences in definitions and approaches in these studies form a barrier against reaching a conclusion regarding the risk factors and consequences of polypharmacy. It is therefore imperative to establish an appropriate definition of polypharmacy.
  
  
  METHODS
  A systematic review will be conducted using PubMed, Scopus, Web of Science, EMBASE, PsycINFO and AgeLine bibliographic databases, as well as the grey literature on polypharmacy in older adults to answer these two questions: What definitions in the literature are being used for polypharmacy in older people?, and Which definitions are more comprehensive and applicable? 2 independent reviewers will conduct the primary screening of the articles and data extraction, and eligible sources will be selected after discussing non-conformities. All extracted data from selected articles will be categorised based on the type of study participants, study design and setting, the methodological quality of primary studies and any other potential source of heterogeneity, and results will be summarised in a table, which will contain the levels of evidence and methodological quality of the included studies. The most comprehensive definition of polypharmacy will be selected from the final list of definitions through an international expert webinar.
  
  
  BACKGROUND
  This research is exempt from ethics approval because the work is carried out on published documents. We will disseminate this protocol in a related peer-reviewed journal.
authors.affiliation: Mental Health Research Center, Tehran Institute of Psychiatry-School of Behavioral Sciences and Mental Health, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Seyede Salehe
authors.initials: SS
authors.lastname: Mortazavi
authors.affiliation: Department of Aging, University of Social Welfare & Rehabilitation Sciences, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Shati
authors.affiliation: Department of Health Sciences Education Development, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Abasali
authors.initials: A
authors.lastname: Keshtkar
authors.affiliation: Mental Health Research Center, Tehran Institute of Psychiatry-School of Behavioral Sciences and Mental Health, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Seyed Kazem
authors.initials: SK
authors.lastname: Malakouti
authors.affiliation: Department of Family Medicine, Charles R Drew University of Medicine and Science, Los Angeles, USA.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Bazargan
authors.affiliation: Department of Psychiatry, University of Michigan, Ann Arbor, Michigan, USA Center for Research on Ethnicity, Culture, and Health, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Shervin
authors.initials: S
authors.lastname: Assari
mesh_terms: D000368:Aged; D000375:Aging; D016206:Databases, Bibliographic; D006801:Humans; D019338:Polypharmacy; D012107:Research Design; D000078202:Systematic Reviews as Topic
keywords: Aging; Polypharmacy; definition; elderly; multimorbidity; systematic review