Elsevier

Heart & Lung

Volume 41, Issue 2, March–April 2012, Pages 107-114
Heart & Lung

Care of Patients with Cardiovascular Disorders
Medication adherence mediates the relationship between marital status and cardiac event-free survival in patients with heart failure

https://doi.org/10.1016/j.hrtlng.2011.09.009Get rights and content

Abstract

Objective

Prognosis is worse in unmarried patients compared with married patients with heart failure (HF). The reasons for differences in outcomes are unclear, but variations in medication adherence may play a role, because medication adherence is essential to achieving better outcomes. The study objective was to determine whether medication adherence mediated the relationship between marital status and cardiac event-free survival in patients with HF.

Methods

Demographic, clinical, and psychosocial data were collected by questionnaires and medical record review for 136 patients with HF (aged 61 ± 11 years, 70% were male, 60% were in New York Heart Association class III/IV). Medication adherence was monitored objectively for 3 months using the Medication Event Monitoring System. Cardiac event-free survival data were obtained by patient/family interview, hospital database, and death certificate review. A series of regression and Cox survival analyses were performed to determine whether medication adherence mediated the relationship between marital status and event-free survival.

Results

Cardiac event-free survival was worse in unmarried patients than in married patients. Unmarried patients were more likely to be nonadherent and 2 times more likely to experience an event than married patients (P = .017). Marital status was not a significant predictor of event-free survival after entering medication adherence in the model, demonstrating a mediation effect of adherence on the relationship of marital status to survival.

Conclusion

Medication adherence mediated the relationship between marital status and event-free survival. It is important to design interventions to increase medication adherence that take into account subgroups, such as unmarried patients, who are at higher risk for nonadherence.

Section snippets

Study Design

This was a secondary data analysis from a prospective, longitudinal study8, 20, 29, 30 in which we examined whether the relationship between marital status and event-free survival was explained by medication adherence in patients with HF.

Samples and Setting

Detailed eligibility criteria and recruitment methods have been published.8, 20, 21, 29, 30 In short, patients were recruited from outpatient cardiology clinics and inpatient cardiology wards in one Southern state. Patients with a confirmed diagnosis of chronic

Patient Characteristics

A total of 136 patients with HF and complete MEMS data were included in the analysis. The mean age of patients in the sample was 61 ± 11 years, and approximately two thirds of patients had advanced HF (NYHA class III or IV) with an average LVEF of 35% ± 14%. The majority of the patients were male (70%) and white (90%). One quarter of the patients did not complete high school.

The majority of participants were married (62%). Significantly more male patients were married (78.6%) than female

Discussion

This is the first study to examine mediation between marital status and outcomes in patients with HF. Unmarried patients with HF had a higher risk of cardiac events21 than married patients. Nonadherent patients had greater risk for having an event compared with adherent patients.20, 30 Our study extends these findings by demonstrating that medication adherence mediates the relationship between marital status and outcomes in patients with HF.

Our results are consistent with other studies in which

Limitations

A few limitations might compromise the generalizability of the findings. First, we did not measure quality of the marital relationship. A poor-quality marital relationship might cause more stress in daily life and exacerbate HF.14, 15 Further research is needed to examine quality of marriage, medication adherence, and outcomes in patients with HF. It is also possible that married patients more closely followed a low-salt diet or engaged in more physical activity compared with unmarried

Conclusions

The major finding of this study was that medication adherence was a mediator of the relationship between marital status and cardiac event-free survival in this sample. Thus, determining patient marital status can help to identify those who are at higher risk of worse medication adherence and poorer outcomes. It is important to design interventions to improve medication adherence and outcomes that take into account subgroups, such as unmarried patients, who are at higher risk for nonadherence

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    This study was supported by funding from the Philips Medical-American Association of Critical Care Nurses Outcomes Grant, American Heart Association Great River Affiliate Post-doctoral Fellowship to Jia-Rong Wu, University of Kentucky General Clinical Research Center (M01RR02602), Grant R01 NR008567 from the National Institute of Nursing Research, and a Center grant to the University of Kentucky, College of Nursing from the National Institutes of Health, National Institute of Nursing Research, 1P20NR010679. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Nursing Research or the National Institutes of Health.

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