Background:
Adherence to risk factor management (RFM) instructions after AMI can promote recovery. The prognostic importance of social support for adherence is not well understood. We examined the relationship between baseline social support and post-AMI RFM adherence, and tested whether depression moderates this association.
Methods:
Using data from 2202 AMI patients enrolled in the 19-site PREMIER study, we longitudinally examined whether low baseline social support (index hospitalization; score <=18 on 5 items from ENRICHD Social Support Inventory) is associated with poor adherence to 13 RFM instructions (medication adherence, warfarin use, follow-up plan/appointments, whom to call, cholesterol monitoring and therapy, diabetes management, weight monitoring and loss, smoking cessation, diet, exercise, cardiac rehabilitation) within the first year of recovery. Patients were asked at 1, 6, and 12 months if they received any of the RFM instructions since their last interview. Poor adherence was defined
a priori
as adhering “very carefully” to less than 50% of the patient-appropriate instructions. Hierarchical repeated-measures Poisson regression evaluated the association between support and adherence, with adjustment for site, sociodemographics, clinical history and presentation, hospital and outpatient care, and depression. Whether depression (PHQ-9 score >=10) modified the association was evaluated by stratifying the risk-adjusted model by depression status and including a support*depression interaction term.
Results:
Patients with low social support had greater unadjusted risk of poor adherence than patients with high social support (RR 1.46, 95% CI 1.27-1.67). This association did not vary with time and remained significant after full risk adjustment (RR 1.24, 95% CI 1.05-1.47). In depression-stratified analyses, the risk-adjusted association of low support with poor adherence was significant among nondepressed (RR 1.44, 95% CI 1.26-1.66) but not depressed (RR 1.03, 95% CI 0.79-1.33) patients (p<0.001 for support*depression interaction).
Conclusion:
Good social support may improve adherence among nondepressed AMI patients, but more research is needed to understand the role of social support among depressed patients.