Table 3.

Results of univariate logistic regression used to explore risk factors for COPD coexisting OSA (AHI > 15 times per hour)

Variables	β	Wald	P	OR	95% CI
Age	0.019	2.017	0.142	1.017	0.992 ~ 1.041
BMI (kg/m2)	0.178	32.158	< 0.001	1.186	1.115 ~ 1.258
Neck circumference	0.186	12.452	< 0.001	1.201	1.114 ~ 1.289
FEV1	0.006	2.457	0.047	1.009	1.000 ~ 1.019
FEV1% of expected value	0.025	0.141	0.463	0.958	0.841 ~ 1.075
FEV1 (%predicted) < 50%	− 0.621	7.412	0.041	0.551	0.412 ~ 0.691
CAT scores	0.201	32.263	< 0.001	1.305	1.121 ~ 1.490
ESS scores	0.137	9.524	< 0.001	1.128	1.074 ~ 1.182
SBQ scores	0.223	17.623	< 0.001	1.311	1.125 ~ 1.498
HADS-A scores	0.243	29.132	< 0.001	1.324	1.131 ~ 1.517
HADS-D scores	0.251	30.541	< 0.001	1.301	1.122 ~ 1.481
Hypertension	0.351	35.022	0.029	2.011	1.551 ~ 2.470
Coronary heart disease	0.133	5.851	0.045	1.148	1.006 ~ 1.291
Diabetes	0.402	37.112	< 0.001	2.055	1.442 ~ 2.669

Overlap syndrome (AHI > 15 times per hour) was considered as the dependent variable and age, BMI, neck circumference, FEV₁, FEV₁% of expected value, FEV₁(%predicted) < 50%, CAT score, ESS score, SBQ scores, HADS-A scores, HADS-D scores, hypertension, coronary heart disease and diabetes as independent variables. BMI body mass index; FEV₁ forced expiratory volume in 1 s; CAT COPD assessment test; ESS Epworth sleepiness scale; SBQ STOP-Bang; HADS-A Hospital Anxiety and Depression Scale for anxiety; HADS-D Hospital Anxiety and Depression Scale for depression