Single-Subject Analysis of an Occupational Therapy Intervention to Promote Medication Adherence

HYPOTHESIS: We hypothesized that a manualized occupational therapy intervention could improve the medication adherence of adults with chronic health conditions.

BACKGROUND: Half of all Americans do not take their medications as prescribed, resulting in declines in health and function. Current interventions for medication adherence are not very effective. New interventions are needed to improve performance in this instrumental activity of daily living.

DESIGN: We used an AB single-subject design with naturally occurring multiple baselines and intersubject replication. This study was conducted within a pre–post, two-group, experimental, blinded randomized controlled trial.

PARTICIPANTS: We recruited a convenience sample of community-dwelling adults with chronic health conditions. Participants were required to independently manage their own medications and demonstrate poor medication adherence evidenced by a score of ≤6 on the Morisky Medication Adherence Scale (MMAS).

METHOD: All participants recorded their medication adherence in a diary for a 2-wk baseline phase. The participants were then randomized to receive a 30-min occupational therapy intervention or a 30-min standard of care.

The manualized occupational therapy intervention encouraged participants to reflect on their medication management behaviors and past performance, set a goal, and develop strategies to reach their goal. The session was client centered and prompted participants to consider strategies related to the activity, advocacy, education, assistive technology, and environmental modifications.

Standard-care participants worked with the study staff to review “Managing Your Medicines,” an educational pamphlet developed by the American Heart Association and American Stroke Association.

Participants were blinded to their assignment. Following the intervention, participants continued to record their medication adherence for 4 wk. Medication diaries were verified with two pill counts and the MMAS (an 8-item yes–no questionnaire).

ANALYSIS: The daily medication adherence calendars provided the data for single-subject analysis. We analyzed the data visually for changes in slope, level, variability, immediacy of the effect, overlap, and consistency of data patterns across similar phases. We also analyzed the data using simulation modeling analysis to determine if changes in slope and level were statically significant.

RESULTS: Simulation modeling analyses revealed that 50% of occupational therapy participants and 14% of standard-care participants demonstrated significant improvements in their medication adherence rates (i.e., level) following their intervention (p < .01).

Visual analyses revealed that the occupational therapy intervention was effective immediately and ameliorated both overdosing and underdosing. For example, 1 occupational therapy participant’s medication adherence ranged from 71% to 129% at baseline and then stabilized at 100% during follow-up. The occupational therapy intervention was effective across persons of different health conditions, race, and age.

DISCUSSION: We recruited 11 adults, ages 18–80 yr, mostly women, with multiple physical and mental health conditions. Higher proportions of occupational therapy participants experienced significant improvements in their ability to take their medication as prescribed compared with persons who received standard care.

IMPACT STATEMENT: These findings provide the proof of concept that medication adherence can be responsive to occupational therapy intervention. This research (1) demonstrates the power and potential of occupational therapy in medication adherence, (2) provides the basis for future research in this area, and (3) begins to give practitioners much needed resources in this area of practice.