Banner -- Identifying Strategies to Collect Drug Usage and Driving Functioning Among Older Drivers


The goal of this project is to determine if there are practical means to obtain information about drug usage by older drivers under everyday, “real-world” conditions that are valid and reliable, and to measure the consequences of multiple drug use for safe driving. Further goals are to identify candidate methodologies for carrying out such studies that are both cost-effective and likely to be successful in obtaining a diverse and representative sample of older drivers.

Project tasks are geared toward accomplishing these four main objectives:

  1. A literature review that updates the findings in the unpublished NHTSA Task Order report “Polypharmacy and Older Drivers” (Wilkinson and Moskowitz, 2001).
  2. A critical literature review of methods currently used to measure the use of prescription medications and over-the-counter drugs by older adults.
  3. Identification of potential cost-effective and practical ways to obtain valid information about prescription medications and over-the-counter drug usage by older drivers.
  4. Identification of potential cost-effective and valid methods to assess the impacts on seniors’ everyday driving performance of the use of prescription medications and over-the-counter drugs.

This literature review updates the Wilkinson and Moskowitz (2001) unpublished report Polypharmacy & Older Drivers ‑- Literature Review . As such, it is limited to literature published since 2001 addressing polypharmacy, drugs, and older drivers. The review has been divided into three major sections to address the information needs of the current project: 1) Medication/Polypharmacy Effects on Older People; 2) Methods of Measuring/Monitoring Medication Usage; and 3) Methods to Measure Driving Performance.

Although prescription medications are the major focus of this review, over-the-counter medication use by older people is included where it was reliably documented in the literature. Additional areas that received attention in the literature review on polypharmacy include:

  • Older people’s use of alcohol in combination with other medications—as alcohol use per se is not the focus of this project.
  • Medication management (compliance and persistence) by older people—these aspects of a patient’s behavior have an impact on functional ability and safe driving, in addition to whether the medications provide the intended therapy for the presenting medical conditions.
  • How polypharmacy among older adults impacts areas other than driving (such as falls).
  • Techniques used to measure/test driving skills and their application to medication studies.

Searches were conducted in Embase (which includes MedLine), PsycINFO, TRIS, and SafetyLit Weekly for current literature (2001 to 2004) combining the following keywords:

  • Polypharmacy
  • Multiple medication use
  • Prescription drugs
  • Over-the-counter drugs
  • Drug use
  • Older drivers
  • Older adults
  • Elderly persons
  • Community-dwelling elderly
  • Medication review
  • Brown-bag method
  • Medication management
  • Medication compliance
  • Medication adherence
  • Medication persistence
  • Medication event monitoring
  • Self-medication
  • Medication side effects
  • Driver impairing medications
  • Driver impairing medical conditions
  • Inappropriate prescribing
  • Contraindicated drugs/medications
  • Geriatrics
  • Gerontology
  • Medicaid/Medicare pharmacy claims
  • Veterans administration pharmacy benefits management database
  • Pharmaceutical claims
  • Prescription database
  • Medication usage/tracking
  • Medication dispensing technology
  • Motor vehicle crashes
  • Motor vehicle accidents
  • Dose administration aids
  • Driving skills
  • Driving ability
  • Driving performance
  • Falls or falling

Approximately 1,600 abstracts were identified in the original searches. A review of titles indicated that many reports focused on medications for resistant conditions. Eliminating the terms “resistance” and “resistant” and limiting the search to human subjects 65 and older, and abstracts to those in English reduced the results to 365 potentially relevant articles. In selecting articles for review, we included research only on populations of likely drivers (i.e., to “community-dwelling” populations, as opposed to residents of nursing homes or residents of group homes who suffer from developmental disabilities or conditions such as schizophrenia). Systematic differences in prescribing and in monitoring compliance in controlled settings such as nursing homes and hospitals limit the generalizability of information from such populations of older people to the population of community-dwelling older people. In addition, research on multiple medication effects was primary over research on single-medication effects; however, reports presenting the effects of single medications on driving performance were included to the degree that the research focused on the effects of the drug on driving performance or falling in older community-dwelling people. The set of 365 potentially relevant abstracts was reduced through this first screen to a set of 300 articles.

The selection of reports for review underwent further refinement with the assistance of two project consultants, Dr. Robert Raleigh and Dr. Marion Anders. Dr. Robert Raleigh is the chief of the Maryland Medical Advisory Board. He reviewed the set of 300 abstracts to assist in the prioritization of candidate documents/studies for review by Dr. Anders. This screening process reduced the number of potentially relevant articles to 143 on the topics of identifying medication use and measuring medication adherence, measuring driver performance, and polypharmacy and older people.

Articles were then retrieved by the staff at the University of North Carolina Highway Safety Research Center (the prime contractor for this project), and through e-mail requests of authors, when articles were not available at UNC/HSRC. Reports received were screened according to selection criteria that include relevance and methodological soundness. Emphasis was placed on well-designed and controlled studies. The subset of articles dealing with polypharmacy effects on older people was mailed to Dr. M. W. Anders—a world renowned expert in interactions of single and multiple drugs. He is recently retired as chair of the Departments of Pharmacology & Physiology at the University of Rochester Medical School . He supported the research team in this task by performing a detailed review and interpretation of the literature with a specific focus on driving impairment (approximately 34 articles). TransAnalytics staff synthesized the literature pertaining to the measurement of driving performance (approximately 16 articles), and methods of measuring medication use/compliance (approximately 48 articles).

Dr. Richard Marottoli’s (Yale University School of Medicine) review and comment on the Medication/Polypharmacy Effects on Older People” section are gratefully appreciated.