Journal Article Annotations
2017, 4th Quarter
Annotation by Paula Zimbrean, MD, FAPM
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.