Absolute decline in FEV1 before and after BOS in azithromycin non-responders

BOS remains an important complication after lung transplantation (LTx) and is defined as a decline of at least 20% compared to the best postoperative FEV1, while the absolute decline(mL) is not considered. We investigated the absolute(mL) and %pred FEV1 rate of decline before and after diagnosis of BOS. Eighteen patients from the ongoing double-blind, placebo controled montelukast study ( NCT01211509 ) with a diagnosis of BOS between 10/2010 and 7/2013 were included. Absolute(mL) and %FEV1 at 6 and 3 months before, at diagnosis of BOS, and 3 and 6 months after the diagnosis were analyzed and compared to the best postoperative value. At BOS diagnosis, patients received montelukast (10 mg/d) or placebo, however, the blinding remained unchanged. Treatment was unchanged and they were taking AZI for mean of 392 (±137) days. The best FEV1 (105±6.3%) declined to 73±4.6% at diagnosis of BOS. FEV1 was 91±5.4% at 6 months and 84±5.4% at 3 months before BOS. A stable FEV1% was observed at 3 months (75±5.1%) and 6 months(72 ±5.5%) after the diagnosis of BOS. Six months before BOS diagnosis, patients already lost 458±76mL. An additional 396±42 mL was lost from 6 months before until BOS was diagnosed . Most of this loss occurred during the last 3 months (232±48mL) before BOS with a decline of 77±14 mL/month, this was only 55 ±12 mL/month between 6 and 3 months before BOS. After BOS diagnosis the FEV1 remained stable the first 3 months and then declined with 24±13 ml/month. This study describes the decline in FEV1 in patients who develop BOS and do not respond to AZI treatment. These values are important to consider in further studies. The FEV1 loss after intervention with montelukast remains to be further elucidated.