Lung transplantation (LTx) is frequently considered for patients with cystic fibrosis (CF) when FEV1 reaches <30%. This study estimated transplant-free survival for CF patients and FEV1 <30% and identified predictors of death without LTx.
We conducted a retrospective cohort study using the CF Foundation Patient Registry, 1/1/2003-12/31/2013. Adult patients (≥18 years) with FEV1 <30% prior to LTx were included. We performed Kaplan-Meier survival estimates censored at LTx. Multivariable Cox proportional hazard regression identified predictors of mortality.
There were 3,340 patients with FEV1 <30%. Death without LTx occurred in 1,250 (37.4%); 951 (28.5%) underwent LTx; 918 (27.5%) remained alive without LTx at the end of follow-up; 221 (6.6%) were lost to follow-up. Median transplant-free survival after FEV1 <30% was 6.6 years (95% CI 5.9-7.0). Adjusted predictors of death without LTx included (HR, 95% CI): supplemental oxygen use (2.1, 1.7-2.6), B. cepacia infection (1.8, 1.3-2.6), BMI ≤18 (1.6, 1.3-1.9), female sex (1.6, 1.2-2.0), CF-related diabetes on insulin (1.4, 1.2-1.8), and ≥1 exacerbations per year (1.7, 1.3-2.2; vs. 0 exacerbations).
Median survival is over 6.5 years for CF patients with FEV1 <30%, exceeding prior survival estimates. There is substantial heterogeneity in survival, with some CF patients dying soon after reaching this lung function threshold and others living for many years. For this reason, we conclude that FEV1 <30% remains an important marker of disease severity for CF patients. Patients with a supplemental oxygen requirement or frequent exacerbations should have prompt referral because of their increased risk of death.