Sleep quality, depressive symptoms, and transplant outcomes: Follow-up analyses from the ADAPT prospective pilot study.

Background: Previous studies suggested that depressive symptoms and sleep quality may be important for long-term clinical outcomes following cardiothoracic transplant. Few studies, however, have systematically examined objective markers of these behavioral factors among ambulatory transplant recipients, or their association with clinical outcomes.
Methods: We examined sleep quality and depressive symptoms with subsequent clinical outcomes (hospitalizations and death) in a sample of 66 lung or heart transplant recipients using a single-center, prospective cohort study. Recipients were assessed at approximately 6 months post-transplant and completed one week of actigraphy assessment to examine sleep quality and self-report measures of mood (Centers for Epidemiologic Studies of Depression [CESD]). Recipients were followed for clinical outcomes.
Results: At 6-months following transplantation, recipients spent the majority of daytime activity at a sedentary level (61% of daily activity [SD = 10]) and elevated depressive symptoms were common (subclinical = 17%, mild = 12%, or moderate = 8%). Over a median follow-up of 4.5 years (IQR = 0.9, 5.1), 51 participants (77%) had at least one unplanned hospitalization and 11 (17%) participants died. In addition, sleep efficiency measurements suggested that a subset of participants exhibited suboptimal sleep (mean efficiency = 87% [SD = 7]). Poorer sleep quality, indexed by lower sleep efficiency and greater sleep fragmentation, was associated with greater depressive symptoms (r's = 0.37-0.50, P < .01). Better sleep quality at 6-months (HR = 0.75 [0.60, 0.95], P = .015), including sleep efficiency (HR = 0.74 [0.56, 0.99], P = .041) and sleep fragmentation (HR = 0.71 [0.53, 0.95], P = .020) were associated with lower risk of hospitalization or death. Compared with individuals without elevated depressive symptoms or sleep difficulties, individuals with either factor (HR = 1.72 [1.05, 2.81], P = .031) or both factors (HR = 2.37 [1.35, 4.18], P = .003) exhibited greater risk of clinical events in adjusted analyses.
Conclusions: Sleep quality is associated with depressive symptoms among cardiothoracic transplant recipients and enhances the prognostic association between biobehavioral risk factors and clinical outcomes.
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