Depression, social support, and clinical outcomes following lung transplantation: a single-center cohort study

Depressive symptoms are common among lung transplant candidates and have been associated with poorer clinical outcomes in some studies. Previous studies have been plagued by methodologic problems, including small sample sizes, few clinical events, and uncontrolled confounders, particularly perioperative complications. In addition, few studies have examined social support as a potential protective factor. We therefore examined the association between pretransplant depressive symptoms, social support, and mortality in a large sample of lung transplant recipients. As a secondary aim, we also examined the associations between psychosocial factors, perioperative outcomes [indexed by hospital length of stay (LOS)], and mortality. We hypothesized that depression would be associated with longer LOS and that the association between depression, social support, and mortality would be moderated by LOS. Participants included lung transplant recipients, transplanted at Duke University Medical Center from January 2009 to December 2014. Depressive symptoms were evaluated using the Beck Depression Inventory (BDI-II) and social support using the Perceived Social Support Scale (PSSS). Medical risk factors included forced vital capacity (FVC), partial pressure of carbon dioxide (PCO₂ ), donor age, acute rejection, and transplant type. Functional status was assessed using six-minute walk distance (6MWD). We also controlled for demographic factors, including age, gender, and native disease. Transplant hospitalization LOS was examined as a marker of perioperative clinical outcomes. Participants included 273 lung recipients (174 restrictive, 67 obstructive, 26 cystic fibrosis, and six "other"). Pretransplant depressive symptoms were common, with 56 participants (21%) exhibiting clinically elevated levels (BDI-II ≥ 14). Greater depressive symptoms were associated with longer LOS [adjusted b = 0.20 (2 days per 7-point higher BDI-II score), P < 0.01]. LOS moderated the associations between depressive symptoms (P = 0.019), social support (P < 0.001), and mortality, such that greater depressive symptoms and lower social support were associated with greater mortality only among individuals with longer LOS. For individuals with LOS ≥ 1 month, clinically elevated depressive symptoms (BDI-II ≥ 14) were associated with a threefold increased risk of mortality (HR = 2.97). Greater pretransplant depressive symptoms and lower social support may be associated with greater mortality among a subset of individuals with worse perioperative outcomes.