The Association Between Sleep Duration, Asthma-Related Episodes/Attacks and Emergency Department Visits

Figures & data

Figure 1 Consort diagram of study population.

Table 1 Demographic and Clinical Characteristics of Study Population

	No Episodes/Attacks (N= 659, 43.2%)	Episodes/Attacks Without ED Visits (N= 588, 38.5%)	Episodes/Attacks with ED Visits (N= 279, 18.3%)	P
Sleep duration				<0.001
≤6 h	273 (41.4%)	285 (48.5%)	165 (59.1%)
7–8 h	297 (45.1%)	250 (42.5%)	85 (30.5%)
≥9 h	89 (13.5%)	53 (9.0%)	29 (10.4%)
Sex				<0.001
Male	186 (28.2%)	152 (25.9%)	46 (16.5%)
Female	473 (71.8%)	436 (74.1%)	233 (83.5%)
Age				<0.001
<65 y	411 (62.4%)	430 (73.1%)	224 (80.3%)
≥65 y	248 (37.6%)	158 (26.9%)	55 (19.7%)
Race				<0.001
White, Non-Hispanic	414 (62.8%)	403 (68.5%)	143 (51.3%)
Black, Non-Hispanic	221 (33.5%)	139 (23.6%)	117 (41.9%)
Other	24 (3.6%)	46 (7.8%)	19 (6.8%)
Marital status				0.018
Currently married	247 (37.5%)	258 (43.9%)	98 (35.1%)
Unmarried	412 (62.5%)	330 (56.1%)	181 (64.9%)
Body mass index				0.04
<25	180 (27.3%)	133 (22.6%)	57 (20.4%)
≥25	479 (72.7%)	455 (77.4%)	222 (79.6%)
Smoking				0.523
Now smokes every day	104 (15.8%)	92 (15.6%)	45 (16.1%)
Now smokes some days	35 (5.3%)	38 (6.5%)	25 (9.0%)
Former smoker	177 (26.9%)	146 (24.8%)	72 (25.8%)
Never smoked	343 (52.0%)	312 (53.1%)	137 (49.1%)
Heavy drinkers				0.879
Yes	26 (3.9%)	24 (4.1%)	13 (4.7%)
No	633 (96.1%)	564 (95.9%)	266 (95.3%)
Physical activity				0.013
Yes	268 (40.7%)	213 (36.2%)	130 (46.6%)
No	391 (59.3%)	375 (63.8%)	149 (53.4%)
Chronic respiratory diseases				<0.001
Yes	247 (37.5%)	230 (39.1%)	149 (53.4%)
No	412 (62.5%)	358 (60.9%)	130 (46.6%)
Myocardial infarction				0.351
Yes	62 (9.4%)	70 (11.9%)	31 (11.1%)
No	597 (90.6%)	518 (88.1%)	248 (88.9%)
Coronary heart disease				0.027
Yes	72 (10.9%)	92 (15.6%)	44 (15.8%)
No	587 (89.1%)	496 (84.4%)	235 (84.2%)
Stroke				0.001
Yes	48 (7.3%)	59 (10.0%)	42 (15.1%)
No	611 (92.7%)	529 (90.0%)	237 (84.9%)
Diabetes				0.002
Yes	155 (23.5%)	135 (23.0%)	93 (33.3%)
No	504 (76.5%)	453 (77.0%)	186 (66.7%)
Connective tissue disease				0.238
Yes	360 (54.6%)	335 (57.0%)	169 (60.6%)
No	299 (45.4%)	253 (43.0%)	110 (39.4%)
Depressive disorder				<0.001
Yes	207 (31.4%)	248 (42.2%)	130 (46.6%)
No	452 (68.6%)	340 (57.8%)	149 (53.4%)
Level of asthma symptom control				<0.001
Well controlled	250 (37.9%)	106 (18.0%)	24 (8.6%)
Partial controlled	325 (49.3%)	316 (53.7%)	106 (38.0%)
Uncontrolled	84 (12.7%)	166 (28.2%)	149 (53.4%)
Asthmatic medical prescription				<0.001
Yes	405 (61.5%)	465 (79.1%)	246 (88.2%)
No	254 (38.5%)	123 (20.9%)	33 (11.8%)

Table 2 Sleep Duration Among Different Asthma Outcomes, Symptom Controlled Level, and Medical Prescription

	Crude Value	Crude RR	P	Adjusted Value*	Adjusted RR*	P
Sleep duration in three asthma outcomes groups
No Episodes/attacks	7.01 (6.81, 7.22)			7.01 (6.59, 7.47)
Episodes/attacks without ED visits	6.63 (6.43, 6.84)	0.94 (0.90, 0.98)	0.01	6.72 (6.32, 7.15)	0.96 (0.92, 1.00)	0.06
Episodes/attacks with ED visits	6.42 (6.13, 6.72)	0.91 (0.87, 0.97)	< 0.01	6.50 (6.03, 7.00)	0.93 (0.88, 0.98)	< 0.01
Sleep duration in different levels of asthma symptom control
Well controlled	6.99 (6.73, 7.26)			6.99 (6.55, 7.46)
Partial controlled	6.74 (6.55, 6.93)	0.96 (0.92, 1.01)	0.12	6.77 (6.36, 7.20)	0.97 (0.92, 1.02)	0.18
Uncontrolled	6.58 (6.33, 6.83)	0.94 (0.89, 0.99)	0.03	6.69 (6.23, 7.18)	0.96 (0.90, 1.01)	0.13
Sleep duration between asthmatics with medical prescription and asthmatics without medical prescription
No	6.78 (6.54, 7.04)			6.79 (6.35, 7.25)
Yes	6.74 (6.60, 6.90)	0.99(0.95,1.04)	0.8	6.76 (6.37, 7.17)	1.00 (0.95, 1.04)	0.86

Note: *Adjusted confounding variables: age, sex, race, marital status, body mass index, smoking, heavy drinkers, physical activity, chronic respiratory diseases, myocardial infarction, coronary heart disease, stroke, diabetes, connective tissue disease, and depressive disorder.

Figure 2 Sleep duration among different asthma outcomes, symptom controlled levels, and medical prescriptions: (A) Sleep duration in three asthma outcomes groups; (B) sleep duration in different levels of asthma symptom control; (C) sleep duration between asthmatics with medical prescription and asthmatics without medical prescription.

Figure 3 The associations among sleep duration, asthma-related episodes/attacks and emergency department visits: (A) The prevalence of asthma-related episodes/attacks in three sleep duration groups; (B) the prevalence of asthma-related emergency department visits in three sleep duration groups; (C) the frequency of asthma-related emergency department visits in three sleep duration groups.

Table 3 The Association between Sleep Duration, Asthma-Related Episode/Attack and Emergency Department Visits

	Crude Value	Crude RR	P	Adjusted Value*	Adjusted RR*	P
The revalence of asthma-related episodes/attacks in three sleep duration groups
≤6 h	0.62(0.59, 0.66)			0.62(0.53, 0.71)
7–8 h	0.53(0.49, 0.57)	0.68(0.55, 0.85)	<0.01	0.59(0.50, 0.68)	0.88(0.69, 1.13)	0.31
≥9 h	0.48(0.40, 0.55)	0.56(0.40, 0.78)	<0.01	0.49(0.37, 0.61)	0.59(0.41, 0.86)	<0.01
The prevalence of asthma-related emergency department visits in three sleep duration groups
≤6 h	0.37(0.32, 0.41)			0.37(0.25, 0.50)
7–8 h	0.25(0.21, 0.30)	0.58(0.43, 0.80)	<0.01	0.28(0.18, 0.41)	0.67(0.47, 0.94)	0.02
≥9 h	0.35(0.26, 0.46)	0.95(0.58, 1.55)	0.82	0.30(0.17, 0.46)	0.73(0.43, 1.25)	0.25
The frequency of asthma-related emergency department visits in three sleep duration groups
≤6 h	2.47(2.24, 2.72)			2.47(1.87, 3.27)
7 h–8 h	1.99(1.71, 2.31)	0.80(0.67, 0.96)	0.017	2.05(1.50, 2.80)	0.83(0.69, 0.9996)	0.0495
≥9 h	2.55(2.03, 3.20)	1.03(0.81, 1.32)	0.8	2.39(1.67, 3.42)	0.96(0.75, 1.24)	0.79

Note: *Adjusted confounding variables: age, sex, race, marital status, body mass index, smoking, heavy drinkers, physical activity, chronic respiratory diseases, myocardial infarction, coronary heart disease, stroke, diabetes, connective tissue disease, depressive disorder, level of asthma symptom control and asthmatic medical prescription.