202169 Health outcomes associated with multiple drug nonadherence in the elderly

Sunday, November 8, 2009

Frank M. Ahern, PhD , Department of Biobehavioral Health, Penn State University, University Park, PA
Debra A. Heller, PhD , First Health Services/The PACE Program, Harrisburg, PA
Jian Ding, MS , Department of Biobehavioral Health, Penn State University, University Park, PA
Judith S. Samkoff, MD, ScM , First Health Services/The PACE Program, Harrisburg, PA
Aimee Read, BS , Department of Biobehavioral Health, Penn State University, University Park, PA
Theresa V. Brown, MPA , The PACE Program, Pennsylvania Department of Aging, Harrisburg, PA
Medication adherence is essential for effective pharmacotherapy. Although a number of studies have examined outcomes associated with nonadherence within individual drug classes, few studies have incorporated concomitant measures of adherence across multiple classes. The goal of this study was to examine associations between nonadherence and subsequent hospitalization risk in a sample of elderly medication users.

We examined prescription refill patterns within 15 therapeutic classes for 67,801 community-dwelling elderly enrolled in Pennsylvania's Pharmaceutical Assistance Contract for the Elderly during 2001-2002. The therapeutic classes included eight cardiovascular categories, antidepressants, anti-ulcer agents, thyroid medications, Alzheimer's medications, overactive bladder treatments, oral hypoglycemics, and osteoporosis medications. For cardholders who filled prescriptions in January 2001, one-year class-specific Medication Possession Ratio (MPR) measures were computed. The MPR represents the proportion of days that medication was available during the cumulative prescribing interval. For each therapeutic class used, cardholders were categorized as adherent or nonadherent using a 0.80 MPR threshold. Multivariate logistic regression was used to examine associations between nonadherence and likelihood of hospital admission during the six months following the initial one-year MPR assessment.

Controlling for demographics, the numbers of classes used adherently (MPR>0.80) and nonadherently (MPR<=.80) independently predicted hospitalization risk. While each adherently-used class increased hospitalization risk by 16% (OR=1.16, p<.0001), each nonadherently-used class increased risk by 27% (OR=1.27, p<.0001). These results suggest that, aside from expected risks associated with polypharmacy and comorbidity, multiple drug nonadherence is independently associated with increased likelihood of hospitalization. Additional details regarding nonadherence patterns, hospitalizations, and other outcomes will also be presented.

Learning Objectives:
1. Describe how administrative pharmacy claims data can be used to assess medication adherence through refill frequency measures. 2. Evaluate the assocation between measures of medication non-adherence and health outcomes in an elderly sample. 3. Assess the impact of nonadherence in multiple drug classes, and discuss how examining multiple drug nonadherence can provide new information about pharmacotherapy effectiveness.

Keywords: Prescription Drug Use Patterns, Outcomes Research

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have training (Ph.D.) and experience (35 years) in research on gerontological health. Other research conducted by my colleagues and myself has been previously presented at APHA as well as other conferences, and has 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.