Table 5 |
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|
Correlation coefficients between components of PSQI, demographic, clinical, and psychogenic variables (Spearman rho) |
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|
Variables |
PSQI |
Subjective sleep quality |
Sleep latency |
Sleep duration |
Habitual sleep efficiency |
Sleep disorders |
Use of sleep medications |
Daytime dysfunction |
|
|
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|
Age (years) |
0.165** |
0.073 |
0.142* |
0.074 |
0.065 |
0.193** |
0.135* |
0.139* |
|
Years of education |
-0.149** |
0.003 |
-0.206** |
-0.083 |
-0.119* |
-0.047 |
-0.186** |
-0.099 |
|
ESR (mm/h) |
0.163** |
0.187** |
0.086 |
0.070 |
0.171** |
0.102 |
0.062 |
0.044 |
|
CRP (mg/dl) |
0.164** |
0.172** |
0.072 |
0.034 |
0.159** |
0.134* |
0.040 |
0.125* |
|
Disease duration (years) |
0.094 |
0.051 |
0.091 |
0.011 |
-0.013 |
0.095 |
-0.014 |
0.133* |
|
Morning stiffness (minutes) |
0.250** |
0.219** |
0.185** |
0.103 |
0.177** |
0.173** |
0.069 |
0.180** |
|
Fingertip-to-floor distance (cm) |
0.04 |
0.040 |
0.010 |
-0.038 |
-0.025 |
0.084 |
0.049 |
0.114* |
|
Overall assessment of health (VAS) |
0.386** |
0.258** |
0.241** |
0.073 |
0.200** |
0.359** |
0.174** |
0.375** |
|
Nocturnal pain (VAS) |
0.487** |
0.324** |
0.337** |
0.181** |
0.330** |
0.364** |
0.129* |
0.388** |
|
Total back pain (VAS) |
0.485** |
0.319** |
0.297** |
0.199** |
0.295** |
0.386** |
0.176** |
0.424** |
|
BASMI |
0.093 |
0.044 |
0.057 |
0.023 |
0.105 |
0.122* |
0.025 |
0.065 |
|
BASDAI |
0.479** |
0.322** |
0.327** |
0.130** |
0.214** |
0.421** |
0.206** |
0.467** |
|
BASFI |
0.312** |
0.198** |
0.168** |
0.052 |
0.119* |
0.421** |
0.128* |
0.313** |
|
SDS |
0.467** |
0.290** |
0.346** |
0.124* |
0.178** |
0.438** |
0.167** |
0.448** |
|
SAS |
0.522** |
0.347** |
0.384** |
0.173** |
0.236** |
0.493** |
0.169** |
0.439** |
|
|
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|
*P < 0.05; **P < 0.01. Spearman rho, <0.3, the weak correlation; Spearman rho, 0.3 to 0.5, the medium correlation; Spearman rho, >0.5, the high correlation. 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. |
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|
Li et al. Arthritis Research & Therapy 2012 14:R215 doi:10.1186/ar4054 |
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