Improving survival outcomes in lung transplant recipients through early detection of bronchiolitis obliterans: Daily home spirometry versus standard pulmonary function testing

BACKGROUND Long-term lung transplant success is limited by bronchiolitis obliterans syndrome (BOS), a form of chronic allograft rejection that manifests in the majority of patients by five years post-transplant. Frequent monitoring of pulmonary function measurements through the use of daily home spirometry may have the capability to detect the onset of BOS sooner than standard pulmonary function testing. Early detection of BOS would confer a treatment advantage that may improve survival outcomes for lung transplant recipients. METHODS A systematic review of current evidence was used to determine the effectiveness of daily home spirometry as a BOS detection tool, in addition to its impact and survival outcomes. Articles were included in the present systematic review if they were randomized control studies and if their purpose(s) included investigation of spirometry as a BOS detection tool in lung transplant patients. RESULTS A primary search of databases yielded 115 unique citations, with an additional four citations identified through a secondary review of the reference lists of retrieved articles. After application of all inclusion and exclusion criteria through abstract and full-text review, eight randomized controlled trials were included in the review. DISCUSSION Forced expiratory volume in 1 s (FEV1) has been identified as the most reliable diagnostic tool for detecting the onset of BOS. Two studies compared the use of traditionally scheduled pulmonary function testing with daily home spirometry and found BOS stage 1 to appear 341 days earlier with home spirometry (P<0.001). Other studies that investigated the impact early detection had on survival showed a positive trend toward freedom from BOS and reduced rates of retransplantation, although these results did not reach statistical significance (P<0.07). CONCLUSION Daily home spirometry has been shown to lead to earlier detection and staging of BOS when compared with standard pulmonary function testing. Although FEV1 has been shown to be the most sensitive and reliable marker of BOS onset, the impact of earlier staging via home spirometry on survival has not been reliably determined.