A consensus report from the Pulmonary Council of the International Society for Heart and Lung Transplantation (ISHLT) set out to standardize the nomenclature of chronic lung allograft dysfunction (CLAD) and its clinical phenotypes to facilitate collaboration among centers investigating the pathogenesis, prevention, and treatment of CLAD.1 CLAD is defined as a substantial and persistent decline (≥20%) from baseline in measured FEV1. The baseline value is computed as the mean of the best 2 post-operative FEV1 measurements (taken >3 weeks apart). CLAD can present either as a predominantly obstructive ventilatory pattern, a restrictive pattern, or a mixed obstructive and restrictive pattern that is not explained by other conditions. Consistent pulmonary function testing (PFT) is the leading strategy for early detection of CLAD. While home spirometry devices may provide more variable results, evidence supports it as a useful modality to detect early changes in graft function and may assist providers in decision making.
A systematic review was conducted to determine the effectiveness of home spirometry as a bronchiolitis obliterans syndrome (BOS) detection tool in lung transplant recipients. Eight randomized control trials were included. Authors conclude that home spirometry may be a reliable and safe alternative for lung transplant recipients although they acknowledge the study did not address the impact of early detection on survival outcomes.2
Finkelstein et al. performed a randomized control trial to determine the relative performance of a computer-based Bayesian triage algorithm compared with a manual nurse-based triage system in terms of patient health and health-related quality of life (QOL) in lung transplant recipients. The trial had 65 lung transplant recipients assigned to either the Bayesian algorithm or nurse triage study arm. Subjects monitored and transmitted spirometry and respiratory symptoms daily to the data center using an electronic spirometer/diary device. Subjects completed the Short Form-36 (SF36) survey at baseline and after 1 year. End points were change from baseline after 1 year in forced expiratory volume at 1 second (FEV1) and quality of life (SF-36 scales) within and between each study arm. A total of 65 subjects (control arm=35, intervention arm=30) yielded an overall adherence of 83% for data collection and 88% adherence during the first year. No significant differences in physical (FEV1) or quality of life (SF-36) measures from baseline after HM triage follow-up for subjects in the two arms, suggesting that subjects’ physiological and functional outcomes were similar regardless of the triage method used to monitor HM data. 3
Fadaizadeh et al. conducted pilot study to evaluate the role of home spirometry in follow up of lung transplant recipients and early detection of complications over a 6-month period. Four subjects were included with 2 of those being matched control subjects. Adherence was 80% and 61% in the active participants. The authors conclude that HS is a viable method for monitoring.4 The team conducted further investigation with a prospective cohort study on 15 lung transplant recipients to assess patient adherence and satisfaction with telespirometry following lung transplant over 6 months. Study participants were instructed to send home spirometry results and their clinical symptoms via SMS message. Patients’ level of satisfaction showed a sense of increased support from medical staff was rated highest (92.9%) while satisfaction with the spirometer was rated lowest (35.7%). Average patient compliance at baseline was 80% compared to 27% at study completion, resulting in an average of 78% throughout the study duration. Authors conclude telespirometry is an efficient method of monitoring lung transplant recipients with increased patient satisfaction and adherence.5
A single center retrospective cohort study included 427 adult patients that received the first lung transplantation (LTx) in a specialized outpatient clinic between 1-1-2010 and 12-31-2013. The primary outcome was allograft survival. The secondary outcomes were patient survival, prevalence of CLAD, hospitalizations within the first year after transplantation, renal function after 5 years, and quality of life within the first 3 years after transplantation. The median adherence was 86% on 6,623 visits and was used as the cut off and as a discriminator between good and suboptimal adherers. Patients with good adherence within the first 3 years yielded more favorable 5-year allograft results (74% vs. 60%, p = 0.003) and patient survival (79% vs. 64%, p<0.001) and lower prevalence of chronic allograft dysfunction (33% vs. 45%, p = 0.011) after 5 years when compared to patients with suboptimal adherence.6
A single center retrospective study of adult lung transplant recipients on long term azithromycin for bronchiolitis obliterans (BOS) was performed to evaluate if macrolide-refractory progression could be identified earlier with home spirometry (HS) compared to office spirometry (OS). A total of 239 lung transplant patients were included. Change in FEV1 +/- 10% from FEV1 at azithromycin initiation for >7 consecutive days in HS or >2 measures in OS were taken as cut-off for response or progression. 67% (161/239) demonstrated progression and an additional 8% (n=19) showed initial response followed by relapse. Time to progression was 29 (13-96) days earlier with HS than in OS. Response or stabilization conferred significant improvement in survival (p=0.005). Authors concluded HS identified azithromycin refractory patients significantly earlier than OS, possibly facilitating aggressive treatment escalation that may improve long-term outcome.7
An observational feasibility study was performed to explore the feasibility of rural home telemonitoring for patients with lung cancer. Five patients received usual care after discharge; and five had telemonitors set up at home for 14 days with daily phone calls for nurse coaching; mid- and end-study data were collected by phone and in homes through two months. One of 5 usual care and 3 of 5 monitored patients completed the study. Authors concluded telemonitored data transmission was feasible in rural areas with high satisfaction and symptom data and physiologic data were inconsistent based on disease. 8 Limitations included small sample size and short-term follow-up.
Wang and associates explored new computer-based approaches for the early detection of bronchopulmonary events in a population of lung transplant recipients following a home monitoring protocol. Twenty-eight transplant recipients had a minimum home monitoring period of 60 days. Spirometry and clinical data were collected daily at home by lung transplant recipients and transmitted weekly to the study data center. The majority of event were captured using forced expiratory volume in 1 second or symptoms (sensitivity, 80–90%) at an acceptable level of false alarms. Mean detections occurred 6.6–10.8 days earlier than the known event records. Based on these findings, the authors concluded the approach was useful for early discovery of pulmonary events.9
According to UpToDate, many centers utilize routine home spirometry but note the limitation of patient compliance with this modality is inconsistent.10