Sex differences in reported and objectively measured sleep in COPD

Figures & data

Figure 1 Flowchart of the study.

Figure 2 Reported sleep disturbances in men and women, with and without COPD.

Table 1 Characteristics of the study population (mean ± SD) or %

Characteristics	Men			Women
	No COPD (n=44)	COPD (n=49)	P-value	No COPD (n=46)	COPD (n=47)	P-value
Age (years)	65±5.7	66±6.0	0.62	63±6.8	64±6.0	0.58
BMI (kg/m^2)	28±4.4	28±4.0	0.61	28±4.8	24±5.1	0.0007
Smoking history			<0.0001			<0.0001
Never smokers	48	0		47	0
Ex-smokers	45	68		40	79
Current smokers	7	33		13	21
FEV1 (% predicted)	100±16	55±18	<0.0001	108±16	54±19	<0.0001
FVC (% predicted)	97±17	81±16	<0.0001	113±17	92±24	<0.0001
SaO2awake (%)	95±1.4	93±2.6	0.0004	95±1.3	93±2.0	<0.0001
CRP* mg/L	1.7 (1.3–2.3)	4.1 (3.2–5.2)	<0.0001	1.9 (1.3–2.9)	2.3 (1.7–3.1)	0.52
IL-6*	1.0 (0.66–1.4)	1.7 (1.3–2.4)	0.02	0.64 (0.40–1.0)	1.5 (1.2–2.1)	0.0007
MPO units	324 (274–383)	264 (224–312)	0.08	218 (149–318)	319 (256–398)	0.06
BNP*	78 (58–106)	99 (73–133)	0.28	79 (63–100)	110 (84–144)	0.07
Reported sleep disturbances	9	37	0.002	55	67	0.25
Obstructive sleep apnea**	49	51	0.75	59	41	0.047
Hypertension***	41	35	0.61	29	28	0.90
Ischemic heart disease***	14	23	0.25	2.4	12.8	0.07
Diabetes***	6.8	12	0.38	9.0	0	0.03

Notes:

* Geometric mean (95% CI);

** AHI ≥10/h;

*** reported in questionnaire by the participant. Data in bold indicates variables with P-value <0.05 for between group comparison.

Abbreviations: AHI, apnea-hypopnea index; BMI, body mass index; BNP, B natriuretic protein; CI, confidence interval; CRP, C-reactive protein; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; IL-6, Interleukin-6; MPO, myeloperoxidase; SaO_2awake, daytime oxygen saturation; SD, standard deviation.

Table 2 Self-reported nighttime symptoms and use of hypnotics (%)

Variables	Men			Women
	No COPD (n=44)	COPD (n=49)	P-value	No COPD (n=46)	COPD (n=47)	P-value
Snoring	59	65	0.59	76	65	0.24
Nocturnal reflux	9.1	16	0.30	18	15	0.71
Nocturnal body movements	14	35	0.02	44	37	0.47
Nocturia	28	35	0.44	51	47	0.68
Difficulties initiating sleep	11	33	0.01	56	41	0.17
Difficulties maintaining sleep	25	43	0.07	38	47	0.38
Early morning awakenings	30	35	0.65	52	63	0.30
Symptoms of restless legs	11	16	0.49	51	61	0.35
Use of hypnotics	0	15	0.009	16	36	0.03

Note: Data in bold indicates variables with P-value <0.05 for between group comparison.

Figure 3 Reported daytime symptoms in men and women, with and without COPD.

Table 3 Results from the polysomnography recordings (mean ± SD) and %

Variables	Men			Women
	No COPD (n=44)	COPD (n=49)	P-value	No COPD (n=46)	COPD (n=47)	P-value
TST (minutes)	408±62	395±82	0.40	361±89	431±87	0.0003
SL* (minutes)	9.3 (6.7–13)	23 (17–31)	<0.0001	20 (14–28)	15 (11–19)	0.21
Awakenings (number)	11±4.6	12±6.4	0.21	10±4.3	12±6.1	0.07
Stage 1–2 (%)	79±8.3	82±8.4	0.08	77±8.2	72±9.2	0.01
Stage 3 (%)	10±7.0	7.7±6.0	0.07	10±6.4	14±8.0	0.007
REM (%)	11±5.4	10±5.5	0.60	13±5.9	13±5.9	0.76
AHI*	10 (7.4–15)	9.5 (7.1–13)	0.66	13 (9.6–18)	8.6 (6.6–11)	0.04
ODI*	8.9 (6.1–13)	7.4 (5.4–10)	0.74	11 (8.1–15)	5.5 (4.0–7.6)	0.02
SaO2sleep	94±1.6	92±2.7	0.0001	95±1.5	92±2.0	<0.0001

Notes:

* Geometric mean (95% CI). Data in bold indicates variables with P-value <0.05 for between group comparison.

Abbreviations: AHI, apnea-hypopnea index; CI, confidence interval; ODI, oxygen desaturation index; REM, rapid eye movement; SaO_2sleep, significantly lower oxygen saturation during the night; SD, standard deviation SL, sleep latency; TST, total sleep time.

Table 4 Characteristics of patients with COPD without and with sleep disturbances (mean ± SD) or %

Characteristics	Men			Women
	No sleep disturbance (n=31)	Sleep disturbance (n=18)	P-value	No sleep disturbance (n=15)	sleep disturbance (n=30)	P-value
Age (years)	67±6.4	63±4.6	0.051	65±5.7	64±6.2	0.36
BMI (kg/m^2)	27±4.4	29±3.3	0.26	24±4.2	25±5.7	0.87
FEV1 % predicted	58±17	51±19	0.21	51±20	55±20	0.54
FVC % predicted	85±16	73±15	0.01	86±27	94±23	0.29
SaO2awake	93±2.8	93±2.5	0.71	93±1.7	93±2.1	0.75
CRP*	3.3 (2.5–4.3)	5.9 (3.6–9.7)	0.03	2.0 (1.1–3.6)	2.5 (1.7–3.7)	0.45
IL-6*	1.6 (1.1–2.4)	2.0 (1.1–3.8)	0.48	1.6 (0.92–2.9)	1.4 (1.0–2.0)	0.64
MPO	224 (182–277)	357 (283–450)	0.006	263 (166–416)	363 (277–474)	0.18
BNP*	101 (69–151)	93 (55–157)	0.71	103 (58–181)	116 (84–159)	0.67
Ischemic heart disease**	13	41	0.03	13	13	0.99
Chronic bronchitis	21	76	<0.0001	40	47	0.67

Notes:

* Geometric mean (95% CI);

** reported in questionnaire by the participant. Data in bold indicates variables with P-value <0.05 for between group comparison.

Abbreviations: BMI, body mass index; BNP, B natriuretic protein; CI, confidence interval; CRP, C-reactive protein; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; IL-6, interleukin-6; MPO, myeloperoxidase; SaO_2awake, daytime oxygen saturation; SD, standard deviation.

Figure 4 Health-related quality of life, measured with St George Respiratory Questionnaire, in men and women with COPD who do not report or do report having sleep disturbances.