Table 3

Pearson correlation coefficients between ESS ∆ and potential anchor ∆ scores

RCT combination
1. autoCPAP+MOSAIC2. autoCPAP+Provent
0–3 months (autoCPAP)
0–6 months (MOSAIC)
0–3 months (autoCPAP)
0–2 weeks (Provent)
FOSQ total −0.56
FOSQ general productivity −0.50
FOSQ social outcome −0.31
FOSQ activity level −0.57
FOSQ vigilance −0.60
SF-36 physical functioning−0.15
SF-36 role physical−0.25
SF-36 bodily pain−0.22
SF-36 general health perception−0.29
SF-36 energy/vitality −0.43
SF-36 social functioning−0.22
SF-36 role emotional−0.14
SF-36 mental health−0.18
SF-36 change in health0.29
SF-36 physical component −0.30
SF-36 mental component−0.23
EQ-5D index−0.07
EQ-5D VAS−0.05
  • Values in bold indicate correlations sufficiently strong enough to use in the anchor-based methods.

  • EQ-5D, EuroQol 5 Dimension Questionnaire; ESS, Epworth Sleepiness Scale; FOSQ, Functional Outcomes of Sleep Questionnaire; RCT, randomised controlled trial; SF-36, 36-Item Short Form Health Survey ; VAS, Visual  Analogue Scale.