Depressive symptoms, physical activity, and clinical events: The ADAPT prospective pilot study

Background: Physical inactivity and depressive symptoms following cardiothoracic transplantation are recognized as potentially modifiable psychosocial factors to improve clinical outcomes. However, few studies have prospectively assessed these in ambulatory, outpatient transplant recipients.

Methods: We conducted a prospective, single-center study examining actigraphy-assessed physical activity (PA) levels over a 1-week period in heart or lung transplant recipients recruited at 6 months (range 4-9) post-transplant. Depressive symptoms (Centers for Epidemiologic Study of Depression [CESD]), quality of life (QoL), and clinical events (transplant-related hospitalization and death) were collected. Clustered Cox proportional hazards models were used to examine the associations between PA, psychological measures, and clinical events.

Results: Among 105 potentially eligible participants, 66 (63%) met inclusion criteria and were enrolled between July, 2016 and May, 2017, including 42 lung and 24 heart transplant recipients. The mean age of the population was 53 years, 41% were women and 18% were black. Participants tended to be sedentary, with the majority of activity spent within the "sedentary" level (61%) and an average daily step count of 7188 (SD = 2595). In addition, participants tended to exhibit subclinical depressive symptoms, (mean CESD = 9.4 [SD = 8]) with only a subset exhibiting levels suggestive of clinical depression (22%). Over a median follow-up of 1.4 years (1.14, 1.62), 21 participants (32%) experienced at least one transplant-related hospitalization, including two deaths. In adjusted survival models, greater intensity of PA (HR = 0.45 [0.24, 0.84] per 0.2 METs, P = .012) was associated with a lower risk of clinical events, whereas greater depressive symptoms (HR = 2.11 [1.58, 2.82] per 9 CESD points, P < .001) at 6 months were associated a higher likelihood of subsequent transplant-related hospitalization and/or death.

Conclusions: Physical inactivity and depressive symptoms at 6 months post-transplant were predictive of subsequent adverse clinical events among ambulatory cardiothoracic transplant recipients. Future studies should examine whether improving these potentially modifiable post-transplant risk factors improves clinical outcomes.