Table 2—

Within-patient and between-patient variability

FEV1 %#PEFAM changeDSS changeβ-agonist %#
Individual measurements taken at treatment weeks 3, 6, 9, and 12
Within-patient13.722.80.4433.4
Between-patient14.338.20.7043.4
Average of 2 measurements taken at treatment weeks 3+6 and 9+12
Within-patient10.819.50.3726.3
Between-patient13.937.40.6842.9
Estimated variabilities for average of 3 measurements+
Within-patient9.016.10.3122.3
Between-patient14.338.20.7043.4
  • Data are presented as SD

  • FEV1: forced expiratory volume in one second

  • PEFAM: morning peak expiratory flow

  • DSS: daytime symptom score

  • #: per cent change from baseline

  • : change from baseline

  • +: data derived as described in Statistical methods section