Depression and Low Social Support Mediate the Association of Marital Stress and 12-Month Cardiac-Specific Quality of Life in Young Adults With Acute Myocardial Infarction.

Objective: This study explored whether and how depression and low social support mediate the association between marital stress and cardiac-specific quality of life (QoL) in young adults (≤55 years) with acute myocardial infarction (AMI).

Methods: Data were obtained from 1593 married/partnered AMI survivors aged 18-55 years enrolled in the VIRGO study (2008-2012). Marital stress (Stockholm Marital Stress Scale) was self-reported at 1 month post-AMI and categorized as absent/moderate or severe. Significant depressive symptoms (Patient Health Questionnaire-9 score ≥10), low social support (ENRICHD Social Support Instrument score ≤3 on ≥2 items and total score ≤18), and cardiac-specific QoL (Seattle Angina Questionnaire) were assessed at 12 months post-AMI. Natural direct effect (NDE) of marital stress and indirect effects (NIE) through depression or low social support and the proportion mediated (PM) were estimated by causal mediation methods with adjustment for baseline QoL and sociodemographic factors.

Results: There was a significant direct effect from severe marital stress to lower cardiac-specific QoL after covariate adjustment (NDE = -4.83, 95% CI = -6.98 to -2.49, p < .001). Categorized depression and low social support mediated 11.5% (NIE = -0.63, 95% CI = -1.15 to -0.10, p = .014) and 13.5% (NIE = -0.69, 95% CI = -1.10 to -0.29, p < .001) of the total effect between marital stress and QoL, respectively. When examined as continuous scores, both mediator effects were of borderline significance (PHQ-9: PM = 38.2%, p = .086; social support: PM = 46.1%, p = .051).

Conclusions: Depression and low social support partially mediated the relationship between marital stress and cardiac-specific QoL, underscoring the need for further exploration of additional mediators to inform more comprehensive secondary prevention strategies.