206505 Prevalence of nonadherence to multiple drug therapies among elderly medication users

Sunday, November 8, 2009

Debra A. Heller, PhD , First Health Services/The PACE Program, Harrisburg, PA
Frank M. Ahern, PhD , Department of Biobehavioral Health, Penn State University, University Park, PA
Judith S. Samkoff, MD, ScM , First Health Services/The PACE Program, Harrisburg, PA
Jian Ding, MS , Department of Biobehavioral Health, Penn State University, University Park, PA
Leroy Latty, BA , First Health Services/The PACE Program, Harrisburg, PA
Theresa V. Brown, MPA , The PACE Program, Pennsylvania Department of Aging, Harrisburg, PA
Although medication nonadherence is recognized as an important barrier to effective disease treatment, relatively few studies have examined dimensions of nonadherence across multiple drug classes. Because the elderly are more likely than younger groups to be prescribed multiple medications, it is important to understand the prevalence of multiple drug nonadherence among older patients.

Using prescription claims from Pennsylvania's Pharmaceutical Assistance Contract for the Elderly (PACE) program, we examined refill patterns within 15 therapeutic classes. For cardholders who filled prescriptions in January 2001, refill frequencies over the subsequent 365 days were evaluated using the Medication Possession Ratio (MPR), which represents the proportion of days that medication was available within the cumulative prescribing interval. The sample included 67,801 community-dwelling elderly who remained non-hospitalized and enrolled in PACE throughout the one-year study. Multivariate logistic regression was used to examine factors associated with nonadherence.

Mean MPRs ranged from 0.860 for osteoporosis drugs to 0.958 for thyroid agents. Polypharmacy increased the likelihood of nonadherence. While 74% of persons taking two classes were fully adherent, only 59% of individuals using five classes had MPR>0.80 for all classes. Among elderly using four or more classes, African-Americans were more likely than whites to experience multiple nonadherence (OR=2.08, p<.0001). Users of diuretics (OR=1.26, p<.0001), osteoporosis drugs (OR=1.33, p<.0001), or overactive bladder treatments (OR=1.35, p=.0005) were also more likely to be nonadherent across multiple classes. These results highlight the importance of examining adherence within the context of all prescribed therapies. Additional results regarding specific nonadherence patterns will also be presented.

Learning Objectives:
1. Describe the prevalence of non-adherence to specific drug therapies, including therapies for depression, cardiovascular diseases, diabetes, and other chronic diseases. 2. Evaluate the prevalence of non-adherence across multiple drug therapies among elderly taking drugs in multiple therapeutic classes. 3. Identify factors associated with multiple drug nonadherence in the elderly.

Keywords: Treatment Adherence, Prescription Drug Use Patterns

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have a Ph.D. and have conducted gerontological and epidemiological research for over 20 years. Presentations resulting from our research team's activities have been previously presented at APHA and other conferences, and prior studies from our team have been published in peer-reviewed journals.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.