Reply to comment on “Risk factors for intensive care unit readmission after lung transplantation: a retrospective 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.

Background Lung transplantation (LT) is an accepted therapeutic modality for end-stage lung disease patients. Intensive care unit (ICU) readmission is a risk factor for mortality after LT, for which consistent risk factors have not been elucidated. Thus, we investigated the risk factors for ICU readmission during index hospitalization after LT, particularly regarding the posttransplant condition of LT patients. Methods In this retrospective study, we investigated all adult patients undergoing LT between October 2012 and August 2017 at our institution. We collected perioperative data from electronic medical records such as demographics, comorbidities, laboratory findings, ICU readmission, and in-hospital mortality. Results We analyzed data for 130 patients. Thirty-two patients (24.6%) were readmitted to the ICU 47 times during index hospitalization. At the initial ICU discharge, the Sequential Organ Failure Assessment (SOFA) score (odds ratio [OR], 1.464; 95% confidence interval [CI], 1.083−1.978; P=0.013) and pH (OR, 0.884; 95% CI, 0.813−0.962; P=0.004; when the pH value increases by 0.01) were related to ICU readmission using multivariable regression analysis and were still significant after adjusting for confounding factors. Thirteen patients (10%) died during the hospitalization period, and the number of ICU readmissions was a significant risk factor for in-hospital mortality. The most common causes of ICU readmission and in-hospital mortality were infection-related. Conclusions The SOFA score and pH were associated with increased risk of ICU readmission. Early postoperative management of these factors and thorough posttransplantation infection control can reduce ICU readmission and improve the prognosis of LT patients.

Lung transplantation has evolved to become an acceptable therapy for individuals with end-stage lung disease. Readmissions rates after lung transplantation remain high as compared to other medical surgical populations. The purpose of this review is to synthesize the current body of knowledge about patterns, risk factors, and outcomes of readmissions after lung transplantation. The literature revealed that the most common admission diagnoses linked to lung transplant readmissions are infections followed by tachyarrhythmias, airway complications, surgical complications, rejection, thromboembolic events, gastrointestinal complications, and renal dysfunction. Risk factors for these readmissions include male gender, longer intensive care unit stay, reintubation, prolonged chest tube air leak, frailty, and discharge to a long-term care facility. Outcomes of multiple readmissions after lung transplantation are associated with decreased survival and increased risk of mortality. Further research is needed to better understand which readmission diagnoses are preventable and whether multidisciplinary interventions can reduce readmission rates among patients after lung transplantation.