Table 2.

Multiple-linear regression models for prediction of hematocrit

Independent Variables	β	SE	P	Model R2
Model A
Mean sleep-time SpO2	−0.51	0.20	0.017	0.47
Epo/sEpoR	0.31	0.08	0.001
Age >45 yr	2.70	2.67	0.320
BMI >25 kg/m2	3.82	2.59	0.151
Free testosterone	−0.02	0.14	0.871
Model B
Mean sleep-time SpO2	−0.50	0.20	0.022	0.47
Epo/sEpoR	0.32	0.07	0.000
Age >45 yr	2.93	2.74	0.294
BMI >25 kg/m2	4.23	2.62	0.117
Total testosterone	0.21	0.57	0.708

Model A, multiple linear regression for prediction of hematocrit including mean sleep-time SpO₂, Epo/sEpoR ratio, being over 45 yr of age, having over 25 kg/m² BMI, and free testosterone as independent variables; model B: multiple linear regression for prediction of hematocrit including mean sleep-time SpO₂, Epo/sEpoR ratio, being over 45 yr of age, having over 25 kg/m² BMI, and total testosterone as independent variables. SpO₂, pulse O₂ saturation; BMI, body mass index. β, regression coefficient; SE, standard error; R²: coefficient of determination.