Table 3

Simple linear and multiple linear regression analyses of demographic and clinical variables in relation to the EASi-QoL disease activity domain

Variable	Simple linear regression			Multiple linear regression
Variable	B	Standardised coefficient	P value	B	Standardised coefficient	P value
Sex				–	–	–
Male	Reference
Female	0.637	0.091	0.138
Age category, years				–	–	–
20–29	Reference
30–59	0.75	0.116	0.162
≥60	0.117	0.015	0.86
Body mass index category				–	–	–
Normal and underweight	Reference
Overweight	−0.084	−0.012	0.854
Obese	0.706	0.109	0.105
Educational level				–	–	–
College, university and above	Reference
Senior high school	0.214	0.033	0.613
Junior high school or below	0.385	0.051	0.44
Marital status				–	–	–
Never married, divorced or widowed	Reference
Being married	−0.163	−0.026	0.67
Occupation type				–	–	–
Seated work	Reference
Seated and standing work	0.209	0.033	0.691
Standing and walking work	1.02	0.1	0.167
Walking and strenuous work	−0.336	−0.045	0.57
Not working	−0.190	−0.023	0.766
Perceived health status
Very good or good	Reference			Reference
Fair	2.058	0.343	<0.001	1.633	0.217	<0.001
Poor or very poor	3.903	0.517	<0.001	2.088	0.578	<0.001
Smoking in the past month				–	–	–
No	Reference
Occasionally	1.089	0.096	0.124
Almost daily	0.311	0.043	0.491
Alcohol use				–	–	–
No	Reference
Yes	0.278	0.046	0.461
Vegetarian diet				–	–	–
No	Reference
Occasionally	1.401	0.104	0.094
Yes	0.562	0.089	0.153
Exercise				–	–	–
No	Reference
Yes	−0.016	−0.003	0.967
Duration of sleep, hours	0.111	0.053	0.39	–	–	–
Duration of AS, years	−0.008	−0.029	0.643	−0.028	−0.094	0.04
mSASSS	0.017	0.062	0.316	–	–	–
ASDAS-CRP	2.409	0.666	<0.001	2.088	0.578	<0.001

Adjusted R²=0.469.
AS, ankylosing spondylitis; ASDAS-CRP, Ankylosing Spondylitis Disease Activity Score-C reactive protein; EASi-QoL, Evaluation of Ankylosing Spondylitis Quality of Life; mSASSS, modified Stoke Ankylosing Spondylitis Spinal Score.