Journal Article Annotations
2017, 4th Quarter

Transplant Psychiatry

Annotation by Paula Zimbrean, MD, FAPM
January 2018

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

PUBLICATION #1 — Transplant Psychiatry

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

Smith PJ, Snyder LD, Palmer SM, et al

Abstract: Transpl Int 2017 Nov 12 (Epub ahead of print)

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.

On PubMed: Transpl Int 2017 Nov 12 (Epub ahead of print)

Annotation

Type of study: Prospective cohort study

The finding: This is a prospective cohort study of 273 lung transplant patient looking at the relationship between pretransplantation depressive symptoms, perceived social support and posttransplantation mortality. The median follow-up was 6 years posttransplantation. The analysis indicates that the association between depressive symptoms, social support and mortality were moderated by the length of stay (LOS). Specifically patient with the posttransplantation LOS over 1 month had substantially higher mortality compared to the counter part with lower LOS.

Strength and weaknesses: This was a carefully designed prospective studiy, with systematic evaluations of depression and perceived social support via validated instruments. The study group was very similar to the non-study group in terms of demographic and medical variables, which reduced the selection bias. The study has several limitations which were addressed by the authors. Subjects had only one assessment for depression, while it is known that mood can vary significantly in the course of medical illness. The study also did not analyze the postoperative medical factors that may contribute to increased mortality. The analysis also included individuals that died during the hospital stay which were given the longest LOS of the group; this may have increased the significance of the LOS as a mediating factor between depression and mortality.

Relevance: The study advances the understanding of the mechanisms through which pretransplant psychiatric variables impact posttransplantation outcomes. Depression has been considered to influence the postoperative risks through different mechanisms: through health related behaviors (such as decreased participation in rehabilitation or poor adherence with medications), elevated inflammatory response, or through higher incidence of postoperative delirium. This is the first study to explore the relationship between pretransplant depression and posttransplantation LOS in this population.