Stages of change for adherence with medication regimens for chronic disease: Development and validation of a measure

Background: The stages-of-change (SOC) model has been used to explain and p redict how behavior change occurs, but it is new as an approach to understa nding why patients fail to take their medications as prescribed. Objective: This study validated a 2-item measure of SOC for adherence with medication regimens in 2 groups of patients prescribed pharmacologic therap y for chronic conditions. Methods: Two cross-sectional studies of attitudes toward medication adheren ce included the same measure of SOC for medication adherence. One was a sam ple of 161 HIV-positive patients in the United States, and the other was an international sample of 731 patients with hypertension. The validity of th e measure of SOC for medication adherence was examined in both convenience samples using previously validated self-reported measures of adherence (the Medication Adherence Scale and a measure of adherence from the Medical Out comes Study), and in the HIV sample using electronic monitoring of adherenc e behavior in 85 patients. Results: Construct validity was demonstrated in both samples by association s between SOC and the previously validated measures of adherence (P < 0.001 ), and predictive validity was supported by significant associations betwee n SOC for medication adherence and electronically monitored medication-taki ng behavior during the next 30 days (P < 0.03). Conclusions: Behavior-change theory suggests that stage-tailored communicat ion strategies are more effective than uniform health-promotion messages. O ur results provide a foundation for the development of interventions for me dication adherence that are tailored to patients' readiness for change. Our validated 2-item measure of SOC for medication adherence can be used to ma tch communication strategies to individual motivation and readiness for adh erence with chronic disease medication regimens.