The use of medications and multiple medications becomes more prevalent with increasing age. This pilot study explored the relationship between polypharmacy and driving functioning through separate but related research activities. A patient-level administrative claims database containing prescription information as well as E-codes identifying the incidence of motor vehicle injuries was mined, yielding combinations of drugs that became inclusion criteria in a following field study of driver performance among 44 older adults (range: 57 to 89; mean: 79). Driving performance evaluations by an OT/CDRS, a brake response time measure, and functional screening measures were conducted for the study sample, whose drug profiles were documented through a 'brown bag' review by a licensed pharmacist. The relationship between medication usage and each of these outcome measures was examined in descriptive data summaries and regression analyses. The driving evaluations were carried out in a dual-brake vehicle also equipped with speed sensor (OBD-2), GPS logger, and two miniature video cameras (driver’s face and forward road views) plus digital recorder. A subsample allowed the same instrumentation package to be installed in their private cars for a week of independent driving; this supported an analysis of within-subject variability in driving behavior during a formal driving evaluation versus independent driving. Additional project activities included a current (to October 2007) review of the literature on the prevalence of prescription medications and effects on driving of specific drugs/drug classes. The feasibility of conducting future studies using large, administrative claims databases was critically examined, with an overview of candidates and evaluation of their suitability for NHTSA research. This report concludes with a discussion of project findings and recommendations for future research. (Author/publisher)
Abstract