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A major concern of acute and critical care nurses is
improving outcomes in patients with heart failure (HF). Despite advances in treatment of HF, rehospitalization rates
and mortality remain high.
Recently, depression has been
identified as an independent risk factor for poor outcomes,
particularly rehospitalization and mortality. Before
appropriate interventions for depression in HF can be
designed, it is imperative that we understand the mechanisms
whereby depression results in poor outcomes. Few
investigators have examined these mechanisms, but two
explanations have been proposed. Physiologically,
depression might contribute to poorer outcomes by increasing
sympathetic nervous system (SNS) activation. Behaviorally,
depression might contribute to poorer outcomes by reducing
adherence to the prescribed treatment regimen.
The purpose of this study is to
explore these mechanisms for the known association between
depression, and increased morbidity and mortality. The
specific aim of this study is to determine whether SNS
arousal and nonadherence mediate the association between
depression and poorer HF outcomes.
This aim will be examined in a
longitudinal correlational study. Three hundred patients
with a confirmed diagnosis of HF will be followed. At
baseline, depression (assessed by the Beck Depression
Inventory), SNS arousal (assessed by heart rate
variability), and adherence (assessed by both self-report
[Medical Outcomes Study Specific Adherence Scale] and
objective evidence [24-hour urine sodium and electronic
medication monitoring device] of adherence) will be
measured. Six months later, the combined end-point of HF
rehospitalization or cardiac mortality will be determined. Data will be analyzed using regression techniques to
determine whether SNS arousal, adherence or both mediate the
relationship between depression and HF outcomes.
Results of this study will
provide vital information about mechanisms linking
depression and poor outcomes that clinicians and researchers
can use in the design of effective interventions.
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