Sleep Problems, Depressive Symptoms, And Functional Status Among Patients With Heart Failure—A Serial Multiple Mediator Model

BACKGROUND Patients with heart failure (HF) are more likely to have sleep problems, such as higher levels of daytime sleepiness, poor sleep quality, as well as more depressive symptoms and worse functional status. However, how sleep problems impact depressive symptoms and functional status remain unclear. OBJECTIVE To explore inter-relationships of sleep problems (daytime sleepiness and sleep quality), depressive symptoms, and functional status among patients with HF. METHOD We performed a secondary analysis of baseline data from 207 adults with HF in this descriptive study (male: 67%, age: 62±12, NYHA class III/IV: 38%). Participants were enrolled from out-patient settings. Sleep problems were assessed using the Epworth Sleepiness Scale (ESS) and the Pittsburg Sleep Quality Index (PSQI). Depressive symptoms were measured using the Beck Depression Inventory-II. Functional status was measured using the Duke Activity Status Index. Linear regression with mediation analysis was used for data analysis. RESULTS Daytime sleepiness was directly associated with sleep quality and depressive symptoms. Higher levels of daytime sleepiness were associated with worse sleep quality and more depressive symptoms. Poorer sleep quality and more depressive symptoms were directly associated with worse functional status. Daytime sleepiness was not directly associated with functional status; but indirectly associated with functional status through the following three paths: 1) sleep quality; 2) depressive symptoms; 3) sleep quality and depressive symptoms (Figure). CONCLUSION Sleep quality and depressive symptoms independently and in combination mediated the relationship between daytime sleepiness and functional status. These findings suggest that it is important to screen patients’ daytime sleepiness, as well as sleep quality and depressive symptoms to identify patients at risk for poor functional status. Patients with heart failure (HF) are more likely to have sleep problems, such as higher levels of daytime sleepiness, poor sleep quality, as well as more depressive symptoms and worse functional status. However, how sleep problems impact depressive symptoms and functional status remain unclear. To explore inter-relationships of sleep problems (daytime sleepiness and sleep quality), depressive symptoms, and functional status among patients with HF. We performed a secondary analysis of baseline data from 207 adults with HF in this descriptive study (male: 67%, age: 62±12, NYHA class III/IV: 38%). Participants were enrolled from out-patient settings. Sleep problems were assessed using the Epworth Sleepiness Scale (ESS) and the Pittsburg Sleep Quality Index (PSQI). Depressive symptoms were measured using the Beck Depression Inventory-II. Functional status was measured using the Duke Activity Status Index. Linear regression with mediation analysis was used for data analysis. Daytime sleepiness was directly associated with sleep quality and depressive symptoms. Higher levels of daytime sleepiness were associated with worse sleep quality and more depressive symptoms. Poorer sleep quality and more depressive symptoms were directly associated with worse functional status. Daytime sleepiness was not directly associated with functional status; but indirectly associated with functional status through the following three paths: 1) sleep quality; 2) depressive symptoms; 3) sleep quality and depressive symptoms (Figure). Sleep quality and depressive symptoms independently and in combination mediated the relationship between daytime sleepiness and functional status. These findings suggest that it is important to screen patients’ daytime sleepiness, as well as sleep quality and depressive symptoms to identify patients at risk for poor functional status.