Medication Use in Older Adult Drivers: AAA LongROAD Study

Abstract

Introduction

The AAA Longitudinal Research on Aging Drivers (LongROAD) utilized data to examine the amount and types of medications used by older drivers. Many medications – such as antihistamines, narcotic analgesics, central nervous system (CNS) drugs, muscle relaxants and tricyclic antidepressants – have been associated with increased crash risk. There was a high medication usage, with 97% of participants taking at least one medication; the median number reported taken was seven. In this study, medication usage was categorized by class and type in the cohort of older drivers enrolled in LongROAD. The most frequently used types of medication were cardiovascular medications, CNS agents, electrolyte pills, hormones and vitamins. Usage varied by age, gender and ethnicity.

Key Findings

• 2,949 of the 2,990 older drivers underwent the medication review
• 7 medications was the median number
• 73% of the study population took Cardiovascular Drugs
• 70% of the study population took Central Nervous system Agents

Methodology

This study utilized cross sectional baseline data from the AAA LongROAD study, a longitudinal study on aging drivers.3 LongROAD is a multisite (San Diego, California; Denver, Colorado; Baltimore, Maryland; Ann Arbor, Michigan; and Cooperstown, New York) prospective cohort study designed to collect data on the medical, behavioral, environmental and technological factors influencing older adults’ driving safety. Participants were eligible if they were 65-79 years old, possessed a valid driver’s license, drove at least once per week on average and had no significant cognitive impairment.

LongROAD collects self-reported and objectively measured information on health status and driving behaviors. The data for this study were based on the medications brought to the study offices for a “brown-bag review” at the baseline in-person assessment. Medication names and dosages were entered into a database and coded based on the American Hospital Foundation Service (AHFS) system.4 The AHFS classification allows the grouping of drugs with similar pharmacologic, therapeutic and/or chemical characteristics in a four-tier hierarchy. Starting with the most general groupings, each increasing tier provides greater specificity regarding drug class.

Results

Among the 2,990 older drivers in the study, 2,949 underwent the brown-bag review. For those drivers, there were 24,690 containers of medication recorded, and 22,856 (92.6%) were coded successfully using the AHFS classification system. The distribution of the number of medications taken by participants was positively skewed: The median number reported taken was seven; 10% took two or fewer; 25% took four or fewer; 25% took 11 or more; 10% took 16 or more; and 1% took 26 or more medications.

The categories with the highest number of medications reported are cardiovascular medications (n=4,700), accounting for 19.0% of all medications reported; vitamins (3,922; 15.9%); central nervous system agents (CNS) (3,921; 15.9%); electrolytic, caloric and water balance pills (2,355; 9.5%); and hormones and synthetic substitutes (2,189; 8.9%). The distribution of drug use varied for most medications by age, sex and ethnicity. For example, at least one cardiovascular medication was used by 73% of the sample, but the rate of use was 10% higher for males (79%) than for females (69%). The use of cardiovascular medication also increased significantly with age: a 68% rate of use for those 65-69 years old, 75% for those 70-74 and 81% for those 75-79. Cardiovascular medication use also varied significantly by race, with the most frequent use among African-American participants (79.7%), followed by white non-Hispanic participants (73.2%) and Hispanic participants (70.9%). Medications taken by a high percentage of the study population included cardiovascular drugs (73%); CNS agents (70%); vitamins (65%); electrolytes (52%); hormones (44%); gastrointestinal drugs (32%); ear, eye, nose and throat preparations (24%) and autonomic drugs (22%). Given the high rate of medications, physicians and pharmacists need to play a role in both cautious prescribing as well as counseling.