A71-09 Association of Early Post-lung Transplant Bronchial Culture Positivity With Chronic Lung Allograft Dysfunction (CLAD) and Mortality

Introduction

Bacterial infections cause complications post-lung transplantation due to their inflammatory and immunogenic effects. We aim to determine whether early bacterial infections increase risk of Chronic Lung Allograft Dysfunction (CLAD) and mortality post-lung transplant, and whether specific bacterial subtypes may portend higher risk.

Methods Used

This retrospective study included adult lung transplant recipients from 1/1/2008-12/31/2019, followed until death or 12/31/2019. Categorical variables were described as percentages and compared using Chi-squared or Fisher’s exact tests. Continuous variables were described using median and interquartile range or mean and 95% confidence interval, and compared using t-test, Kruskal-Wallis, or Anova test. Bronchoalveolar lavage cultures within 6 months were grouped into gram-positive cocci (GPC), gram-negative rods (GNR), and culture-negative; patients with both were analyzed separately. We evaluated the effect of early infection on survival with Cox proportional hazard models conditional on six-month survival, adjusted for Lung Allocation Score (LAS) and Primary Graft Dysfunction Grade 3 (PGD3), comparing all groups as categorical variables, and each of the infection groups independently to the culture-negative group. The outcomes of interest were survival and CLAD.

Results of the study

The study included 572 lung transplant recipients, median age 57.2 years, (IQR 45.2- 64.0), 41% female, transplanted for ILD (42.5%), COPD (26.6%), CF (17.5%), PVD (1.4%) and other diagnoses (8%) with median transplant LAS of 40.8 (IQR 34.7-52). Median follow-up was 4.7 years (IQR 2.8-7). Baseline characteristics were similar across culture groups, except the GPC/GNB group was younger and with higher prevalence of cystic fibrosis. Compared with recipients without infection, CLAD risk elevated in patients who had any infection (hazard ratio (HR) 1.302, 95% CI 1.012-1.676) or any GPC growth (HR 1.559, 95% CI 1.132-2.145, p = 0.006). CLAD risk in patients growing GNR and GPC, compared to all other culture groups, was elevated (HR 1.670, 95% CI 1.164-2.397, p = 0.005). When comparing mortality between culture groups, the GNR group (HR 1.511, 95% CI 1.084-2.106) and GPC/GNR group (HR 2.601, 95% CI 1.77-3.808, p < 0.001) had significantly higher mortality risk. When compared to patients with negative cultures, there was significantly elevated mortality risk with any early infection (HR 1.755, 95% CI 1.310-2.352, p < 0.001), only GNR (HR 1.52, 95% CI 1.091-2.12, p = 0.13), any GPC (HR 2.205, 95% CI 1.549-3.138, p < 0.001) and any GNR (HR 1.802, 95% CI 1.336-2.430, p < 0.001).

Conclusions

Early infections are associated with higher risk of CLAD and mortality. Early infection post-lung transplant is a potentially modifiable risk factor for CLAD and mortality.

This abstract is funded by: None