Pulmonary Function Influences the Performance of Berlin Questionnaire, Modified Berlin Questionnaire, and STOP-Bang Score for Screening Obstructive Sleep Apnea in Subjects with Chronic Obstructive Pulmonary Disease

Figures & data

Figure 1 Flow diagram for participants in this study.

Table 1 Demographic Data and Characteristics of the COPD Subjects

Characteristics	Whole Group (n= 116)	COPD Without OSA (n= 54)	Overlap Syndrome (n= 62)	P value
Age (years)	63 (57, 68)	64 (59, 69)	62 (56, 68)	0.5331
Male, n (%)	101, (87.07%)	43, (79.63%)	58, (93.55%)	0.0260^a
BMI (kg/m^2)	25.04±4.36	23.11±3.43	26.72±4.41	<0.0001^a
BMI≥25kg/m^2, n (%)	55, (47.41%)	17, (31.48%)	38, (61.25%)	0.0020^a
Neck circumference (cm)	38.59±2.43	38.28±1.93	38.85±2.79	0.1477
Current smoker, n (%)	89, (76.72%)	41, (88.89%)	48, (77.42%)	0.8490
Pack×year of smoking	800 (600, 1000)	775 (600, 850)	800 (500,1400)	0.4060
Use alcohol, n (%)	75, (64.66%)	35, (64.81%)	40, (64.52%)	0.9730
Arousal index	5.4 (0.9, 18.5)	0.3 (0.1, 0.6)	19.2 (7.9, 30.5)	<0.0001
AHI	6.5 (1.6, 21.8)	1.2 (0.4, 2.5)	20.3 (9.3, 33.9)	<0.0001^a
REMS (%)	16.52±15.56	11.00±3.55	20.20±20.78	0.5536
Minimum nocturnal SaO2	86.5 (80.5, 90)	89 (87, 91)	82.5 (76, 87)	<0.0001^a
Mean nocturnal SaO2	95.35 (94, 96.55)	96 (94, 97)	95 (93, 96)	0.0048^a
FEV1/FVC (%)	60.62 (55.09, 67.57)	64.62 (50.69, 67.80)	64.70 (57.7, 67.28)	0.8076
FEV1%pred	62.40±19.05	61.7±18.83	63.18±19.55	0.6282
FVC%pred	78.14±15.76	77.86±13.71	78.39±17.49	0.9864
CAT score	12 (9, 16)	12 (9, 14)	12 (9, 17)	0.2546
mMRC score	1.33±0.86	1.54±0.72	1.15±0.94	0.0150^a
BQ score	1 (0, 2)	0 (0, 1)	2 (1, 2)	<0.0001^a
MBQ score	1.22±0.93	0.70±0.72	1.68±0.86	<0.0001^a
BQ part1 score	2 (0, 3)	0 (0, 2)	3 (2, 4)	<0.0001^a
BQ part2 score	0 (0, 0)	0 (0, 0)	0 (0, 1)	<0.0001^a
BQ part3 score	0.30±0.46	0.15±0.36	0.44±0.50	0.0008^a
MBQ part3 score	0.51±0.50	0.35±0.48	0.65±0.48	0.0014^a
STOP-Bang score	3.15±1.34	2.43±1.07	3.77±1.23	<0.0001^a
Hypertension, n (%)	25, (21.55%)	8, (14.81%)	17, (27.42%)	0.1000
Diabetes, n (%)	5, (4.31%)	1, (1.85%)	4, (6.45%)	0.3700
Cardiovascular disease, n (%)	9, (7.76%)	3, (55.56%)	6, (9.68%)	0.5000
Renal insufficiency, n (%)	3, (2.59%)	0, (0%)	3, (4.84%)	0.2470
Dyslipidemia, n (%)	3, (2.59%)	2, (3.70%)	1, (1.61%)	0.5970
AECOPD, n (%)	10, (8.62%)	3, (55.56%)	7, (11.29%)	0.3340

Notes: Data are presented as mean±SD, median (IQR), or n (%); ^aSignificant statistical difference between COPD without OSA group and overlap syndrome group.

Abbreviations: COPD, chronic obstructive pulmonary disease; OSA, obstructive sleep apnea syndrome; BMI, body mass index; AHI, Apnea–Hypopnea Index; REMS, rapid eye movement sleep; SaO₂, oxygen saturation; mMRC, Modified Medical Research Council; CAT, COPD assessment test; BQ, Berlin Questionnaire; MBQ, modified Berlin Questionnaire; AECOPD, acute exacerbations of chronic obstructive pulmonary disease; FEV1/FVC, forced expiratory volume in 1 second and forced vital capacity ratio; FEV1%pred, percentage of predicted forced expiratory volume in 1 second; FVC%pred, percentage of predicted forced vital capacity ratio.

Table 2 Correlation Between Potentially Risk Factors and Apnea–Hypopnea Index

Variable	Whole Group (n = 116)		COPD Without OSA (n = 54)		Overlap Syndrome (n = 62)
	r	P value	r	P value	r	P value
Age (years)	−0.0016	0.9868	0.1352	0.3298	0.0691	0.5935
Neck circumference (cm)	0.1095	0.2419	0.0658	0.6363	−0.0422	0.7448
BMI (kg/m^2)	0.4814	≤0.0001^a	0.0321	0.8179	0.4524	0.0002^a
FEV1/FVC (%)	0.1089	0.2446	0.0638	0.6465	0.2333	0.0704
FEV1%pred	0.0986	0.2926	0.1767	0.2011	0.0415	0.7507
FVC%pred	−0.0236	0.8026	0.1843	0.1822	−0.1683	0.1948

Note: ^aSignificant correlation with Apnea–Hypopnea Index.

Abbreviations: r, correlation coefficient; COPD, chronic obstructive pulmonary disease; OSA, obstructive sleep apnea syndrome; BMI, body mass index; FEV1/FVC, forced expiratory volume in 1 second and forced vital capacity ratio; FEV1%pred, percentage of predicted forced expiratory volume in 1 second; FVC%pred, percentage of predicted forced vital capacity ratio.

Table 3 Multivariate Regression for Parameters Associated with Apnea–Hypopnea Index

Variable	Whole Group (n = 116)		COPD Without OSA (n = 54)		Overlap Syndrome (n = 62)
	B	P value	B	P value	B	P value
Age (years)	−0.2057	0.2620	0.0119	0.6400	−0.6981	0.0270^a
Neck circumference (cm)	−2.416	0.0010^a	−0.0105	0.9020	−2.301	0.0150^a
BMI (kg/m2)	2.669	<0.0001^a	0.0343	0.6710	1.889	0.0010^a
FEV1/FVC (%)	0.3142	0.1970	−0.0812	0.0680	0.6955	0.0540
FEV1%pred	−0.1223	0.3840	0.0489	0.1920	0.0483	0.6490
FVC%pred	0.0248	0.8360	0.0121	0.4730	−0.4349	0.3060

Notes: ^aSignificant correlation with Apnea–Hypopnea Index; Age, neck circumference, BMI, FEV1/FVC, FEV1%pred, and FVC%pred were entered into the multivariable model.

Abbreviations: COPD, chronic obstructive pulmonary disease; OSA, obstructive sleep apnea syndrome; BMI, body mass index; FEV1/FVC, percentage of forced expiratory volume in 1 second and forced vital capacity ratio; FEV1%pred, percentage of predicted forced expiratory volume in 1 second; FVC%pred, predicted forced vital capacity ratio.

Table 4 Performance of Berlin Questionnaire, Modified Berlin Questionnaire, and STOP-Bang in Identifying OSA Among COPD Subjects

Questionnaire	Prevalence of OSA (n/N [%]) =62/116 (53.45%)
	Sensitivity	Specificity	PPV	NPV	AUC
BQ	0.53	0.89	0.85	0.62	0.71 (0.64–0.79)
MBQ	0.65	0.85	0.83	0.68	0.75 (0.67–0.83)
STOP-Bang	0.84	0.59	0.70	0.76	0.72 (0.64–0.80)

Note: Data in parentheses are 95% CIs or n/N (%).

Abbreviations: AUC, area under the curve; OSA, obstructive sleep apnea syndrome; PPV, positive predictive value; NPV, negative predictive value; BQ, Berlin Questionnaire; MBQ, modified Berlin Questionnaire.

Table 5 Univariate Logistic Regression Analysis of Pulmonary Function Parameters Affecting the Risk of Misdiagnosis with Questionnaires

	Whole Group n= 116		COPD Without OSA n= 54		Overlap Syndrome n= 62
	OR (95% CI)	P value	OR (95% CI)	P value	OR (95% CI)	P value
BQ score
FEV1/FVC (%)	1.025 (0.9799,1.072)	0.2851	4.016 (1.122, 14.37)	0.0330^a	0.9749 (0.9190, 1.034)	0.4002
FEV1%pred	1.028 (1.004,1.051)	0.0194^a	1.112 (1.027, 1.205)	0.0091^a	1.014 (0.9873, 1.040)	0.3150
FVC%pred	1.036 (1.007,1.065)	0.0130^a	1.090 (0.9988, 1.191)	0.0530	1.032 (1.001, 1.063)	0.0413^a
MBQ score
FEV1/FVC (%)	1.028 (0.9796,1.078)	0.2644	1.617 (1.006, 2.599)	0.0472^b	0.9691 (0.9130, 1.029)	0.3029
FEV1%pred	1.034 (1.009,1.060)	0.0084^b	1.075 (1.015, 1.139)	0.0143^b	1.021 (0.9923, 1.050)	0.1551
FVC%pred	1.044 (1.013,1.076)	0.0052^b	1.047 (0.9819, 1.117)	0.1593	1.041 (1.008, 1.076)	0.0150^b
STOP-Bang score
FEV1/FVC (%)	1.024 (0.978,1.073)	0.3082	1.048 (0.9892, 1.111)	0.1110	0.9964 (0.9218, 1.077)	0.9290
FEV1%pred	1.031 (1.007,1.056)	0.0120^c	1.035 (1.001, 1.070)	0.0453^c	1.039 (0.9978, 1.083)	0.0644^c
FVC%pred	1.040 (1.011, 1.071)	0.0080^c	1.048 (1.001, 1.097)	0.0450^c	1.053 (1.007, 1.101)	0.0241^c

Notes: The data are presented as the odds ratio (OR) (95% CI); we performed univariate logistic regression. Pulmonary function parameters significantly associated with the risk of ^aBQ, ^bMBQ, and ^c STOP-Bang misdiagnosis.

Abbreviations: CI, confidence interval; OR, odds ratio; COPD, chronic obstructive pulmonary disease; OSA, obstructive sleep apnea syndrome; BQ, Berlin Questionnaire; MBQ, modified Berlin Questionnaire; FEV₁/FVC, forced expiratory volume in 1 second and forced vital capacity ratio; FEV1%pred, percentage of predicted forced expiratory volume in 1 second; FVC%pred, percentage of predicted forced vital capacity ratio.

Table 6 Pulmonary Function Parameters Were Correlated with Body Mass Index and Neck Circumference

	Whole Group n= 116		COPD Without OSA n=54		Overlap Syndrome n=62
	r	P value	r	P value	r	P value
BMI (kg/m^2)
FEV1/FVC	0.1582	0.0899	0.3323	0.0141^a	−0.0023	0.9859
FEV1%pred	−0.0227	0.8087	0.2817	0.0391^a	−0.2550	0.0454^a
FVC%pred	−0.2269	0.0143^a	0.0140	0.9199	−0.3616	0.0042^a
Neck circumference (cm)
FEV1/FVC	0.0538	0.5666	0.1910	0.1666	−0.0867	0.5030
FEV1%pred	−0.1364	0.1443	0.4386	0.1076	−0.2885	0.0230^b
FVC%pred	−0.1715	0.0657^b	0.0263	0.8500	−0.2660	0.0367^b

Notes: ^aSignificant correlation between pulmonary function parameters and BMI; ^bsignificant correlation between pulmonary function parameters and neck circumference.

Abbreviations: r, correlation coefficient; COPD, chronic obstructive pulmonary disease; OSA, obstructive sleep apnea syndrome; BMI, body mass index; FEV₁/FVC, forced expiratory volume in 1 second and forced vital capacity ratio; FEV1%pred, percentage of predicted forced expiratory volume in 1 second; FVC%pred, percentage of predicted forced vital capacity ratio.

Table 7 Correlation Between Body Mass Index and Pulmonary Function Parameters

BMI	BMI<25kg/m^2 n=61		BMI≥25kg/m^2 n=55
	r	P value	r	P value
FEV1/FVC	0.3773	0.0027^a	0.0329	0.8116
FEV1%pred	0.2939	0.0215^a	−0.2963	0.0280^a
FVC%pred	0.1636	0.2076	−0.3046	0.0251^a

Notes: ^aSignificant correlation between pulmonary function parameters and BMI.

Abbreviations: r, correlation coefficient; BMI, body mass index; FEV₁/FVC, forced expiratory volume in 1 second and forced vital capacity ratio; FEV1%pred, percentage of predicted forced expiratory volume in 1 second; FVC%pred, percentage of predicted forced vital capacity ratio.