Table 2– Minimal important difference (MID) estimates for residual volume (RV)
ΔRV LΔRV %ΔRV/TLC %
Anchor-based method
 FEV1-0.43 (-0.62– -0.24)-8.6 (-5.7– -9.5)-4.0 (-5.9– -2.2)
 6MWD-0.41(-0.59– -0.23)-8.4 (-4.9– -11.9)-3.9 (-5.5– -2.3)
 SGRQ total score-0.35 (-0.45– -0.24)-6.9 (-4.9– -8.8)-3.2 (-4.2– -2.3)
Distribution-based method-0.31-6.1-2.8
  • Data are presented as MID (95% CI). Δ: change; TLC: total lung capacity; FEV1: forced expiratory volume in 1 s; 6MWD: 6-min walk distance; SGRQ: St George’s Respiratory Questionnaire.