Efficacy of a Transtheoretical Model-Based Expert System For Antihypertensive Adherence

Blood pressure is not controlled in as many as 50%-75% of hypertensive patients, primarily because of inadequate adherence to treatment. This paper examines the efficacy of a Transtheoretical Model (TTM)-based expert system intervention designed to improve adherence with antihypertensives in a sample of 1,227 adults. Participants were proactively recruited and randomly assigned to receive usual care or three individualized expert system reports and a stage-matched manual over 6 months. Participants were surveyed at baseline, and 6, 12, and 18 months. Significantly more of the intervention group participants reported being in Action and Maintenance at follow-up time points (ie, 73.1% of the treatment group versus 57.6% of the control group at 12 months and 69.1% of the treatment group versus 59.2% of the control group at 18 months). Scores on a behavioral measure of nonadherence differed significantly at follow-up time points. TTM-based expert system interventions have the potential for a significant impact on entire populations of individuals who fail to adhere, regardless of their readiness to change.