184419 Is it possible to identify specific subgroups with poor adherence to antihypertensive drugs? Evaluation of factors associated with suboptimal adherence

Sunday, October 26, 2008

Michelle Ulmer, BA , Research and Development Service, VA New York Harbor Healthcare System, New York Campus, New York, NY
Donald Robinaugh, MA , Research & Development Service, VA New York Harbor Healthcare System, New York Campus, New York, NY
Muhammad Dhanani, BA , Research and Development Service, VA New York Harbor Healthcare System, New York Campus, New York, NY
Marilena Antonopoulos, PharmD , Long Island University, Brooklyn, NY
Ashley Regazzi , Research & Development Service, VA New York Harbor Healthcare System, New York Campus, New York, NY
Sundar Natarajan, MD, MSc , Research and Development Service, VA New York Harbor Healthcare System, New York Campus & New York University, New York, NY
Despite the effectiveness of pharmacological treatments for uncontrolled hypertension, adherence to antihypertensive drugs remains low. To better inform interventions that promote medication adherence, it is critical to understand the factors that affect adherence. We evaluated several factors that could influence adherence to antihypertensive drugs in a closed medical system.

Medication adherence was assessed using an algorithm based on refill dates gathered from a computerized pharmacy system. Using the algorithm rather than relying on self-report, which is more commonly used for measuring adherence, allows for a less biased assessment. Using linear and logistic regression analyses, we examined the association between medication adherence and sociodemographics, medication characteristics, co-morbidities, behavioral constructs and instrumental social support.

We evaluated data from 265 hypertensive veterans (96.7 % male, mean age 65.8). On linear regression, poorer adherence was found in adults who were widowed (-13%, p<.05) or divorced (-9%, p<.05) compared to married participants. Other predictors [Odds Ratios, (95% CI)] of optimal adherence were: age [1.03 (1.00-1.06)], number of medications [0.73, (0.56-0.96)], and higher self-efficacy [1.11 (1.02-1.21)]. Lastly, there seems to be an inverse association between instrumental social support and medication adherence [0.97 (0.93-1.0)].

Our results suggest that we can identify subgroups that are associated with poor adherence, such as younger adults and widowed or divorced individuals who no longer have the support of their spouse, and tailor intensive approaches to improve adherence. Furthermore, increasing self-efficacy, decreasing reliance on social support geared toward medication adherence, and reducing the number of prescribed hypertensive medications should also improve adherence.

Learning Objectives:
1) Understand the factors that influence medication adherence for asymptomatic chronic conditions among veterans 2) With hypertension as the example, articulate how individual, social and environmental factors affect medication adherence 3) Discuss how simple, easily obtainable information can be used to focus efforts on those who are likely to be less adherent to their medication

Keywords: Adherence, Hypertension

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have received my BA from NYU in psychology. I recently submitted an original manuscript, which is under review. I have also done a round table presentation at APHA last year and poster presentation at SGIM last year as well.
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.

See more of: Cardiovascular Disease Epidemiology Poster Session
See more of: Epidemiology