Table 6– Baseline impedance measurements of asthma patients who had infrequent and frequent exacerbations
Impedance parameterPatients with infrequent# exacerbationsPatients with frequent exacerbationsp-value+
Subjects n2541
R5R20 kPa·L−1·s0.070 (0.040–0.130)0.130 (0.075–0.260)0.0065
SampEn R5R200.014 (0.003–0.101)0.114 (0.057–0.281)0.0004
AX kPa·L−10.700 (0.345–1.345)1.270 (0.860–3.100)0.0041
SampEn AX0.922 (0.417–1.212)1.216 (0.992–1.454)0.0041
R20 kPa·L−1·s0.320 (0.285–0.405)0.410 (0.340–0.485)0.0034
SampEn R20 kPa·L−1·s0.057 (0.014–0.139)0.136 (0.059–0.282)0.0044
  • Data are presented as median (interquartile range), unless otherwise stated. R5R20: resistance at 5 Hz minus resistance at 20 Hz; SampEn: sample entropy; AX: reactance area; R20: resistance at 20 Hz. #: fewer than two exacerbations during the previous year; : two or more exacerbations during the previous year; +: Mann–Whitney U-test.