Effectiveness of a Behavior Change Wheel-Informed WeChat-Based Messaging Intervention to Improve Medication Adherence After Percutaneous Coronary Intervention: 12-Week Quasi-Experimental Study

Background: Medication nonadherence after percutaneous coronary intervention (PCI) remains a major barrier to secondary prevention. Prior SMS text messaging interventions have shown inconsistent results, often limited to reminders without addressing behavioral or psychological determinants. Objective: This study aimed to evaluate the effectiveness of a theory-informed, WeChat-based messaging intervention for improving medication adherence and patient-reported outcomes after PCI. Methods: A nonrandomized quasi-experimental parallel-group study was conducted from July 2022 to March 2023 at a tertiary hospital in Hangzhou, China. Patients were allocated by ward admission to the intervention or control group. The intervention comprised 12-week WeChat-based medication reminders and theory-informed messages mapped to capability, opportunity, and motivation-behavior model domains and behavior change techniques. The primary outcome was medication adherence measured using the 8-item Morisky Medication Adherence Scale (MMAS-8); secondary outcomes were medication beliefs, self-efficacy, and disease-specific health status measured using the Beliefs About Medicines Questionnaire (BMQ)-Specific, Self-Efficacy for Appropriate Medication Use Scale, and Seattle Angina Questionnaire (SAQ), respectively. Outcomes were assessed at baseline and 12 weeks by blinded assessors and analyzed using baseline-adjusted analysis of covariance based on the observed outcome data for all 92 participants. Sensitivity analyses included a per-protocol analysis restricted to the 87 participants who completed the full assigned care protocol and a difference-in-differences analysis comparing changes from baseline to 12 weeks between groups. Results: Of 180 patients screened, 92 (51.1%) were enrolled, of whom all completed the 12-week outcome assessment and 87 (94.6%) completed the full assigned care protocol. At 12 weeks, medication adherence was higher in the intervention group than in the control group (adjusted mean MMAS-8 score 7.40, SE 0.05 vs 6.22, SE 0.10; adjusted mean difference 1.18, 95% CI 0.96-1.40; P<.001). Secondary outcomes generally favored the intervention, including the BMQ necessity (adjusted mean difference 1.62, 95% CI 1.06-2.17) and concerns (adjusted mean difference -3.25, 95% CI -3.87 to -2.63) subscales, medication self-efficacy (adjusted mean difference 4.04, 95% CI 3.21-4.87), and the SAQ summary score (adjusted mean difference 6.13, 95% CI 4.72-7.53; P<.001 in all cases). SAQ treatment satisfaction did not differ significantly between groups (adjusted mean difference 0.40, 95% CI -2.02 to 2.82; P=.74). Both the per-protocol and difference-in-differences sensitivity analyses yielded findings consistent with the primary analysis, supporting the robustness of the results. Conclusions: A theory-informed, WeChat-based messaging intervention was associated with improvements in medication adherence, medication beliefs, self-efficacy, and disease-specific health status after PCI. Larger, adequately powered randomized trials with longer follow-up are needed to confirm these findings. ©Yong Fang, Wenxiao Wu, Dili Chen, Zhili Jiang, Mingyue Zhang, Fanghong Dong, Xinyue Xiang, Lihua Huang. Originally published in the Journal of Medical Internet Research (https://www.jmir.org).