A pharmacoepidemiologic study of community-dwelling, disabled older women: Factors associated with medication use

Background: Although disabled older adults may be among the subpopulation of adults with the highest risk for adverse drug events (ADEs), reliable data on their use of medications are limited. Objectives: The aims of this study were to describe the extent and patterns of medication use in communitydwelling, disabled older women, and to identify factors associated with medication use in this population. Methods: Cross-sectional analyses of baseline data on medication use from the Women's Health and Aging Study I (WHAS I) were performed. WHAS I was an observational study of 1002 community-dwelling women aged ≥65 years who self-reported difficulty in at least 2 of 4 domains of physical functioning (ie, upper-extremity functions, mobility, self-care, and higher functioning tasks needed for independent living in the community). After descriptive analyses of their prescription and over-the-counter (OTC) drugs, associations between participants' characteristics and medication utilization were determined, using generalized linear models. Results: Of the 975 participants, 580 (59.5%) used ≥5 medications and 115 (11.8%) used ≥10 medications (prescriptions and OTCs). The mean number of medications used was 3.9 for prescription drugs and 1.9 for OTC drugs. Cardiovascular drugs and analgesics were the most frequently used prescription and OTC drugs, respectively. Participants with complete outcome and covariate data (n = 803) were included in the multivariate analyses. Cancer was associated with a 13% increase in total medication use (95% CI, 1.00-1.27). Multimorbidity (1.08; 95% CI, 1.02-1.15), frailty (1.13; 95% CI, 1.02-1.26), high Mini-Mental State Examination score (1.03; 95% CI, 1.01-1.05), congestive heart failure (CHF) (1.39; 95% CI, 1.23-1.58), angina (1.27; 95% CI, 1.12-1.44), chronic obstructive pulmonary disease (COPD) (1.20; 95% CI, 1.05-1.37), diabetes mellitus (DM) (1.24; 95% CI, 1.07-1.43), difficulty with shopping for personal items such as medicines and toiletries (1.20; 95% CI, 1.06-1.35), and possession of health insurance (1.21; 95% CI, 1.04-1.40) or a prescription plan (1.16; 95% CI, 1.05-1.29) were independently associated with increased use of prescription drugs. A diagnosis of osteoarthritis of the hands (1.29; 95% CI, 1.12- 1.49) and having a spouse (1.19; 95% CI, 1.01-1.40) were associated with increased use of OTC drugs. Participants with DM (0.78; 95% CI, 0.65-0.94), African Americans (0.70; 95% CI, 0.60-0.82), and those who had difficulty shopping (0.85; 95% CI, 0.72-0.99) used fewer OTCs than did participants without these characteristics. Conclusions: Most of the disabled older women in this study took ≥5 medications at baseline, potentially putting them at high risk for ADEs. Those with multimorbidity, frailty, CHF, angina, DM, COPD, cancer, and difficulty with instrumental activities of daily living are target subpopulations for polypharmacy intervention.