Early pulmonary isolation of non-tuberculous mycobacterial organisms is associated with increased risk of death and CLAD: A Lung Transplant Outcomes Group Cohort Study

BACKGROUND: How pulmonary non-tuberculous mycobacteria (NTM) impact lung transplant outcomes is unknown. We evaluated the effect of pulmonary isolation of NTM on death or re-transplantation and chronic lung allograft dysfunction (CLAD). METHODS: We performed a multicenter cohort study of adult lung transplant recipients at five US centers from 2007-2022. Our exposure was growth of NTM from pulmonary samples in the first year post-transplant ("early") in primary analyses, and growth at any time post-transplant in secondary analyses. We evaluated time from transplantation to death or re-transplantation and CLAD using separate covariate-adjusted proportional hazards models, each with a time-dependent exposure indicator for early first pulmonary NTM isolation. RESULTS: Of 1,766 lung transplant recipients, 223 (13%) had early pulmonary NTM isolation. NTM was first isolated at a median [interquartile range] of 61 [17-158] days after transplantation. Early NTM growth was associated with increased risk of death or re-transplantation (HR 1.30, 95% CI 1.05-1.60), driven by rapid growing NTM (HR 2.17, 95% CI 1.42-3.31). Early growth of NTM was associated with increased risk of CLAD (HR 1.29, 95% CI 1.03-1.62); this association was driven by slow growing NTM (HR 1.33, 95% CI 1.04-1.69). Association appeared modified by acute cellular rejection (p=0.10) and pre-operative diagnosis (p=0.04), with a stronger association in recipients with ILD (HR 1.67, 95% CI 1.26-2.20). Similar associations were present for NTM growth at any time post-transplant. CONCLUSIONS: Pulmonary growth of NTM in the first post-transplant year occurred frequently and was associated with increased risk of death or re-transplantation and CLAD.