Correlation and Agreement of Handheld Spirometry with Laboratory Spirometry in Allogeneic Hematopoietic Cell...

Early detection of subclinical lung function decline may help identify allogeneic hematopoietic cell transplant (HCT) recipients who are at increased risk for late noninfectious pulmonary complications, including bronchiolitis obliterans syndrome. We evaluated the use of handheld spirometry in this population. Allogeneic HCT recipients enrolled in a single-center observational trial performed weekly spirometry with a handheld spirometer for 1 year after transplantation. Participants performed pulmonary function tests in an outpatient laboratory setting at 3 time points: before transplantation, at day 80 after transplantation, and at 1 year after transplantation. Correlation between the 2 methods was assessed by Pearson and Spearman correlations; agreement was assessed using Bland-Altman plots. A total of 437 subjects had evaluable pulmonary function tests. Correlation for forced expiratory volume in 1 second (FEV1) was r = .954 (P < .0001) at day 80 and r = .931 (P < .0001) at 1 year when the handheld and laboratory tests were performed within 1 day of each other. Correlation for handheld forced expiratory volume in 6 seconds (FEV6) with laboratory forced vital capacity was r = .914 (P < .0001) at day 80 and r = .826 (P < .0001) at 1 year. The bias, or the mean difference (handheld minus laboratory), for FEV1 at day 80 and 1 year was -.13 L (limits of agreement, -.63 to .37) and -.10 L (limits of agreement, -.77 to .56), respectively. FEV6 showed greater bias at day 80 (-.51 L [limits of agreement, -1.44 to .42]) and 1 year (-.40 L [limits of agreement, -1.81 to 1.01]). Handheld spirometry correlated well with laboratory spirometry after allogeneic HCT and may be useful for self-monitoring of patients for early identification of airflow obstruction.