Abnormal one-year post-lung transplant spirometry is a significant predictor of increased mortality and chronic lung allograft dysfunction.

BACKGROUND

The prognostic value of evaluating spirometry at a fixed time point using standardized population reference has not previously been evaluated. Our aim was to assess the association between spirometric phenotype at 12 months (Spiro12M), survival and incidence of chronic lung allograft dysfunction (CLAD) in bilateral lung transplant recipients.

METHODS

We conducted a retrospective cohort study of bilateral lung transplant recipients transplanted between January 2003 and September 2012. We defined Spiro12M as the mean of the 2 prebronchodilator FEV1 measurements 12-month post-transplant. Normal spirometry was defined as FEV1/FVC ≥0.7 and FEV1≥80% and FVC≥80% predicted population-based values for that recipient. Abnormal spirometry was defined as failure to attain normal function by 12-months. We used a Cox regression model to assess the association between Spiro12M, survival, and CLAD. We used logistic regression to assess potential pretransplant donor and recipient factors associated with abnormal Spiro12M

RESULTS

One hundred and eleven (51%) lung transplant recipients normalized their Spiro12M. Normal Spiro12M was associated improved survival (hazard ratio [HR] 0.60, 95% confidence interval [CI] 0.41-0.88], p = 0.009. Each 10% decrement in FEV1 increased the risk of death in a stepwise fashion. Additionally, CLAD was reduced in those with normal Spiro12M (HR:0.65, 95%CI:0.46-0.92, p = 0.016). Donor smoking history (OR:2.93, 95% CI:1.21-7.09; p = 0.018) and mechanical ventilation time in hours (OR:1.03, 95% CI:1.004-1.05; p = 0.02) were identified as independent predictors of abnormal Spiro12M.

CONCLUSIONS

Abnormal Spiro12M is associated with increased mortality and the development of CLAD. The effect is dose dependent with increased dysfunction corresponding to increased risk. This assessment of phenotype at 12-months can easily be incorporated into standard of care.