Body Mass Index, Gender, and Ethnic Variations Alter the Clinical Implications of the Epworth Sleepiness Scale in Patients with Suspected Obstructive Sleep Apnea§

Table 4.: Correlation Coefficients of the Epworth Sleepiness Scale with Severity of Sleep-Disordered Breathing in Groups and Subgroups of the Study Population

Group	Correlation with RDI	Correlation with Lowest SaO₂
Overall	0.17^**	-0.20^**
Males	0.21^**	-0.22^**
Females	0.09^*	-0.14^**
Caucasian	0.14^**	-0.22^**
Hispanic	0.19^**	-0.24^**
Other ethnicities	0.15	-0.16
Obese	0.17^**	-0.20^**
Non-obese	0.10^*	-0.09
OSA	0.20^**	-0.25^**
No OSA	0.01	-0.01

Subgroup combinations
Obese Caucasian males	0.21^**	-0.21^**
Non-obese Caucasian males	0.07	-0.08
Obese Hispanic males	0.18^**	-0.22^**
Non-obese Hispanic males	0.29^**	-0.27^**
Obese males – other ethnicities	0.14	-0.19
Non-obese males – other ethnicities	-0.36	-0.05
Obese Caucasian females	0.03	-0.04
Non-obese Caucasian females	0.03	-0.03
Obese Hispanic females	0.10	-0.21^*
Non-obese Hispanic females	0.08	-0.03
Obese females – other ethnicities	0.22	-0.02
Non-obese females – other ethnicities	0.80	-0.80

^* P < 0.05.

^** P < 0.001.

RDI = respiratory disturbance index; SaO2 = oxyhempglobin percentage; OSA = obstructive sleep apnea (RDI ≥15).