Sleep disturbances are associated with increased pain, disease activity, depression, and anxiety in ankylosing spondylitis: a case-control study

Table 4 Comparison between poor and good sleepers (sorted by P value)

Variables	PSQI ≤7	PSQI >7	P
	n= 203	n= 111
SDS	44.15 ± 9.44	52.95 ± 9.83	0.000
SAS	45.78 ± 7.07	53.07 ± 7.77	0.000
BASDAI	2.98 ± 1.87	4.66 ± 2.03	0.000
BASFI	1.23 ± 1.83	2.39 ± 2.51	0.000
Nocturnal pain (VAS)	2.89 ± 2.64	5.17 ± 2.94	0.000
Total back pain (VAS)	3.12 ± 2.49	5.18 ± 2.57	0.000
Overall assessment of health (VAS)	4.67 ± 2.79	6.59 ± 2.58	0.000
Morning stiffness (minutes)	9.53 ± 26.48	16.24 ± 29.70	0.002
Age (years)	26.83 ± 8.03	29.70 ± 8.59	0.002
ESR (mm/h)	14.51 ± 15.44	20.98 ± 23.21	0.018
CRP (mg/dl)	1.32 ± 1.65	2.16 ± 5.33	0.039
Years of education	4.46 ± 0.89	4.25 ± 0.98	0.058
BASMI	1.29 ± 1.87	1.59 ± 1.93	0.069
Disease duration (years)	5.70 ± 4.57	6.74 ± 5.40	0.116
Fingertip-to-floor distance (cm)	9.65 ± 13.51	9.99 ± 14.09	0.859

BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; BASMI, Bath Ankylosing Spondylitis Metrology Index; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; PSQI, Pittsburgh Sleep Quality Index; SAS, Self-rating Anxiety Scale; SDS, Self-rating Depression Scale; VAS, visual analogue scale.