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Table 3 Parameter estimates for the ESS scores of the models predicting EQ-5D utility scores

From: Examining the impact of excessive daytime sleepiness on utility scores in patients with obstructive sleep apnoea and/or narcolepsy in five European countries

Model

Estimate

SE

P

(a) GLM—ESS score as a continuous variable

-0.0068

0.0009

 < 0.001

(b) GLM—US/RoW cutoffs (reference 0–10)

 Mild EDS (ESS, 11–12)

-0.0134

0.0174

0.44

 Moderate EDS (ESS, 13–15)

-0.0505

0.0165

0.002

 Severe EDS (ESS, 16–24)

-0.1132

0.0159

 < 0.001

(c) GLM—UK cutoffs (reference 0–10)

 Mild EDS (ESS, 11–14)

-0.0268

0.0138

0.05

 Moderate EDS (ESS, 15–18)

-0.0789

0.0167

 < 0.001

 Severe EDS (ESS, 19–24)

-0.1513

0.0236

 < 0.001

(d) Piecewise linear with breakpoint at 11.29

 ESS Slope 1 (ESS, < 11.29)

-0.0028

0.0018

0.13

 ESS Slope 2 (ESS, > 11.29)

-0.0134

0.0031

 < 0.001

(e) Linear spline with breakpoint at 11

 ESS, 0–11

-0.0026

0.0016

0.11

 ESS, 12–24

-0.0131

0.0022

 < 0.001

  1. Note: P-values for models a-c were calculated using Wald chi-square tests. P-values for models d-e were calculated using t-tests. Due to no adjustments for multiplicity, P-values presented are nominal
  2. EDS Excessive daytime sleepiness, ESS Epworth Sleepiness Scale, GLM Generalized linear model, RoW Rest of world, SE Standard error, UK United Kingdom, US United States