TABLE 1

Correlation matrix and regression coefficients

	Correlation							Regression
	BFI	ESS	BMI	Dyspnoea at rest	Dyspnoea on exertion	Age	Gender	b	95% CI	β	p-value
AHI	r_s=−0.188 p=0.033	r_s=0.022 p=0.797	r_s=0.367 p<0.001	r_s=−0.070 p=0.431	r_s=−0.063 p=0.473	r_s=0.165 p=0.048	r_s=−0.170 p=0.043	−0.031	−0.056–−0.006	−0.193	0.016
BFI		r_s=0.183 p=0.039	r_s=0.183 p=0.039	r_s=0.495 p<0.001	r_s=0.521 p<0.001	r_s=−0.148 p=0.096	r_s=0.205 p=0.020
ESS			r_s=0.054 p=0.524	r_s=0.371 p<0.001	r_s=0.097 p=0.272	r_s=−0.201 p=0.017	r_s=0.017 p=0.844	0.008	−0.063–0.080	0.017	0.821
BMI				r_s=0.064 p=0.469	r_s=0.217 p=0.013	r_s=−0.060 p=0.478	r_s=−0.022 p=0.790	0.051	−0.005–0.107	0.147	0.074
Dyspnoea at rest					r_s=0.507 p<0.001	r_s=−0.101 p=0.252	r_s=0.154 p=0.081	0.290	0.116–0.463	0.290	0.001
Dyspnoea on exertion						r_s=−0.029 p=0.743	r_s=0.042 p=0.632	0.250	0.103–0.396	0.291	0.001
Age							r_s=−0.097 p=0.251
Gender								0.568	−0.043–1.118	0.136	0.068

Bold type indicates statistically significant results of p<0.05 (two-sided). BFI: Brief Fatigue Inventory; ESS: Epworth Sleepiness Scale; BMI: body mass index; b: regression coefficient; β: standardised regression coefficient; AHI: apnoea–hypopnoea index.