Two Randomized Controlled Pilot Trials of Social Forces to Improve Statin Adherence among Patients with Diabetes

Medication nonadherence is an important obstacle to cardiovascular disease management. To improve adherence through real-time feedback based on theories of how social forces influence behavior. Two randomized controlled pilot trials called PROMOTE and SUPPORT. Participants stored statin medication in wireless-enabled pill bottles that transmitted adherence data to researchers. Adults with diabetes and a history of low statin adherence based on pharmacy refills (i.e., Medication Possession Ratio [MPR] < 80 % in the pre-randomization screening period). In PROMOTE, each participant was randomized to 1) weekly messages in which that participant's statin adherence was compared to that of other participants (comparison), 2) weekly summaries of that participant's statin adherence (summary), or 3) control. In SUPPORT, each participant identified another person (the Medication Adherence Partner [MAP]) to receive reports about that participant's adherence, and was randomized to 1) daily reports to MAP, 2) weekly reports to MAP, 3) reports to MAP only if dose was missed, or 4) control. Adherence measured by pill bottle. Among 45,000 health plan members contacted by mail, < 1 % joined the trial. Participants had low baseline MPRs (median = 60 %, IQR 41-72 %) but high pill-bottle adherence (90 % in PROMOTE, 92 % in SUPPORT) during the trial. In PROMOTE (n = 201) and SUPPORT (n = 200), no intervention demonstrated significantly better adherence vs. control. In a subgroup of PROMOTE participants with the lowest pre-study MPR, pill-bottle-measured adherence in the comparison arm (89 %) was higher than the control (86 %) and summary (76 %) arms, but differences were non-significant (p = 0.10). Interventions based on social forces did not improve medication adherence vs. control over a 3-month period. Given the low percentage of invited individuals who enrolled, the studies may have attracted participants who required little encouragement to improve adherence other than study participation.