Effect of adherence on daytime sleepiness, fatigue, depression and sleep quality in the obstructive sleep apnea/hypopnea syndrome patients undertaking nasal continuous positive airway pressure therapy

Figures & data

Table 1 Demographic and relative clinical information of 76 OSAS patients at baseline

Items	Value
Age (years)	48.12±14.46
Sex
Male	58 (76.3)
Female	18 (23.7)
Occupation
Official	39 (51.3)
Businessmen	17 (22.4)
Freelance	8 (10.5)
Retired	6 (7.9)
Others	6 (7.9)
BMI (kg/m^2)	26.97±3.33
Waist-and-hip-ratio	0.96±0.06
AHI (hour^−1)	51.24±27.24

Notes: Mean ± standard deviation; n (%).

Abbreviations: OSAS, obstructive sleep apnea/hypopnea syndrome; BMI, body mass index; AHI, apnea/hypopnea index.

Figure 1 The crude relationship between adherence and ESS and FSS scores in each 3-week period.

Notes: Each point represents one study subject. ESS, Epworth Sleepiness Scale (0–24, higher score indicated sleepier); FSS, Fatigue Severity Scale (9–63, higher score indicated more fatigue).
Abbreviations: h, hour; wk, weeks.

Figure 2 The crude relationship between adherence and SDS and PSQI scores in each 3-week period.

Notes: Each point represents one study subject. SDS, Zung’s Self-Rating Depression Scale (20–80, higher score indicated more depressed) and PSQI, The Pittsburgh Sleep Quality Index (0–21, higher score indicated lower sleep quality).
Abbreviations: h, hour; wk, weeks.

Table 2 Distributions of adherence levels at each therapy phase (N=76 in each therapy phase)

Adherence	Therapy phases (week)
	0 n (%)	1–3 n (%)	4–6 n (%)	7–9 n (%)	10–12 n (%)
Adherence range
0 hour	76 (100)	–	–	–	–
<4 hours	–	6 (7.9)	15 (19.7)	18 (23.7)	15 (19.7)
4–6 hours	–	57 (75.0)	23 (30.3)	12 (15.8)	14 (18.4)
≥6 hours	–	13 (17.1)	38 (50.0)	46 (60.5)	47 (61.8)

Table 3 Distributions of ESS, FSS, SDS and PSQI scores across adherence levels through 12-week nCPAP therapy

Items	Adherence levels				P*-value
	0 hour	<4 hours	4–6 hours	≥6 hours
	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)
ESS
0	12.66 (4.92)
1–3 weeks		5.17 (1.72)	5.96 (2.54)	5.69 (2.25)	0.725
4–6 weeks		8.13 (2.72)^a	6.96 (2.40)^a	5.45 (2.73)^b	0.003
7–9 weeks		8.44 (2.68)^a	6.75 (2.99)^a,b	5.98 (2.76)^b	0.009
10–12 weeks		8.93 (2.60)^a	6.43 (3.08)^b	5.26 (2.59)^b	<0.001
P#		0.126	0.078	0.498
FSS
0	44.39 (11.60)
1–3 weeks		A,B39.67 (14.40)	A37.93 (13.40)	A38.54 (9.67)	0.946
4–6 weeks		A51.67 (11.36)^a	A41.96 (11.95)^b	A,B30.32 (11.67)^c	<0.001
7–9 weeks		A50.39 (13.14)^a	A46.08 (11.52)^a	B29.41 (12.52)^b	<0.001
10–12 weeks		B45.33 (11.81)^a	B35.86 (11.43)^b	C26.55 (11.56)^c	<0.001
P#		<0.001	<0.001	<0.001
SDS
0	37.39 (5.17)
1–3 weeks		A42.67 (2.88)^a	A34.98 (5.91)^b	A31.23 (5.33)^c	0.001
4–6 weeks		A44.73 (4.23)^a	A35.96 (5.67)^b	B29.29 (4.36)^c	<0.001
7–9 weeks		A44.56 (5.38)^a	A37.08 (5.03)^b	B29.54 (5.14)^c	<0.001
10–12 weeks		B41.40 (4.84)^a	B33.79 (5.25)^b	C26.57 (4.30)^c	<0.001
P#		<0.001	<0.001	<0.001
PSQI
0	5.25 (2.58)
1–3 weeks		A7.17 (2.79)	A5.00 (2.79)	A4.31 (2.21)	0.104
4–6 weeks		B5.87 (2.67)^a	B2.30 (1.77)^b	B1.05 (1.18)^c	<0.001
7–9 weeks		B5.67 (2.89)^a	B2.50 (1.62)^b	B1.22 (1.07)^c	<0.001
10–12 weeks		B6.67 (2.64)^a	B2.00 (1.18)^b	B0.83 (0.84)^c	<0.001
P#		<0.001	<0.001	<0.001

Notes: In the row with P<0.05, the values that do not share a common superscript (right side small letters, such as a, b, c) differ significantly from one another (P<0.05, two-sample t-test). In the column with P<0.05, the values that do not share a common superscript (left side capital letters, such as A, B, C) differ significantly from one another (P<0.05, mixed-effects regression).

* One-way ANOVA analysis;

# mixed-effect regression. ESS, Epworth Sleepiness Scale (0–24, higher score indicated sleepier); FSS, Fatigue Severity Scale (9–63, higher score indicated more fatigue); SDS, Zung’s Self-Rating Depression Scale (20–80, higher score indicated more depressed); PSQI, The Pittsburgh Sleep Quality Index (0–21, higher score indicated lower sleep quality).

Abbreviations: nCPAP, nasal continuous positive airway pressure; ANOVA, analysis of variance; SD, standard deviation.

Table 4 Mixed-effects models of influencing factors of ESS, FSS, SDS and PSQI scores during 3-month nCPAP therapy

Variables	ESS	P-value	FSS	P-value	SDS	P-value	PSQI	P-value
Adherence range		<0.001		<0.001		<0.001		0.023
0 hour	0^a		0^a		0^a		0^a
<4 hours	−4.49 (−5.62, −3.36)^b		0.70 (−1.18, 2.59)^a		1.35 (0.41, 2.29)^b		0.30 (−0.24, 0.83)^a
4–6 hours	−6.69 (−7.40, −5.99)^c		−6.02 (−7.14, −4.91)^b		−2.40 (−2.95, −1.85)^c		−0.20 (−0.52, −0.12)^b
≥6 hours	−8.35 (−9.26, −7.44)^d		−10.30 (−11.78, −8.83)^c		−4.42 (−5.15, −3.68)^d		−0.40 (−0.82, −0.02)^b
Therapy phases		0.030		<0.001		<0.001		<0.001
1–3 weeks	0^a		0^a		0^a		0^a
4–6 weeks	0.86 (0.11, 1.62)^b		0.49 (−0.71, 1.69)^a		−0.37 (−0.97, 0.22)^a		−2.67 (−3.01, −2.32)^b
7–9 weeks	1.20 (0.40, 2.00)^b		−0.36 (−1.65, 0.93)^a		−0.37 (−1.01, 0.27)^a		−2.57 (−2.94, −2.21)^b
10–12 weeks	0.84 (0.04,1.63)^b		−5.08 (−6.35, −3.81)^b		−3.66 (−4.29, −3.03)^b		−2.83 (−3.19, −2.47)^b
Agecen, years	NS		NS		0.12 (0.04, 0.21)	0.003	NS
Sex						0.013		<0.001
Female	NS		NS		3.57 (0.77, 6.38)		2.21 (1.07, 3.35)
BMIcen, kg/m^2	0.36 (0.20, 0.52)	<0.001	NS		NS		NS
Constant	12.65 (11.97, 13.34)	<0.001	44.40 (41.59, 47.20)	<0.001	36.55 (35.18, 37.92)	<0.001	4.73 (4.14, 5.31)	<0.001

Notes: The potential influence predictors on ESS, FSS, SDS and PSQI initially included in mixed-effects models were age, sex, BMI, AHI, adherence levels, therapy phases and the interaction between adherence level and therapy phase. For these variables with >2 levels, coefficients not sharing a common superscript (a,b,c, or d) differ significantly (P<0.05, Wald test). Age_cen, deviation of age from mean; BMI_cen, deviation of BMI from mean. ESS, Epworth Sleepiness Scale (0–24, higher score indicated sleepier); FSS, Fatigue Severity Scale (9–63, higher score indicated more fatigue); SDS, Zung’s Self-Rating Depression Scale (20–80, higher score indicated more depressed); PSQI, The Pittsburgh Sleep Quality Index (0–21, higher score indicated lower sleep quality).

Abbreviations: nCPAP, nasal continuous positive airway pressure; NS, nonsignificant; BMI, body mass index; AHI, apnea/hypopnea index.

Figure 3 Adjusted relationships between adherence range and the changes in ESS, FSS, SDS and PQSI scores from baseline within each 3-week period during first 3 months of nCPAP therapy.

Notes: (A) Adjusted relationship between the change in ESS score from baseline and adherence range within each 3-week period during first 3 months of nCPAP therapy; the mean of adjusted ESS score at baseline was 12.66. (B) Adjusted relationship between the change in FSS score from baseline and adherence range within each 3-week period during first 3 months of nCPAP therapy; the mean of adjusted FSS score at baseline was 44.40. (C) Adjusted relationship between the change in SDS score from baseline and adherence range within each 3-week period during first 3 months of nCPAP therapy among males; the mean of adjusted SDS score at baseline was 36.55. (D) Adjusted relationship between the change in PSQI score from baseline and adherence range within each 3-week period during first 3 months of nCPAP therapy among males; the mean of adjusted PSQI score at baseline was 4.73. ESS, Epworth Sleepiness Scale (0–24, higher score indicated sleepier); FSS, Fatigue Severity Scale (9–63, higher score indicated more fatigue); SDS, Zung’s Self-Rating Depression Scale (20–80, higher score indicated more depressed); PSQI, The Pittsburgh Sleep Quality Index (0–21, higher score indicated lower sleep quality).
Abbreviations: nCPAP, nasal continuous positive airway pressure; h, hours; wk, weeks.