Table 2

Results of the univariate linear regression analyses of FSS on sociodemographic, clinical and self-reported health status

Variable	β	SE	t Value	p Value	R² (%)
Sex (male vs female)	−1.61	0.25	−6.46	<0.001	7.7
Age	0.02	0.01	2.14	0.03	0.91
Hypertension ever (yes vs no)	0.98	0.29	3.38	0.008	2.25
Cancer ever (yes vs no)	0.75	0.55	1.37	0.17	0.47
Arthritis duration	0.02	0.013	1.40	0.16	0.39
Psoriasis duration	0.02	0.01	2.07	0.04	0.86
No of active joints	0.11	0.013	8.50	<0.001	12.7
No of swollen joints	0.09	0.03	2.86	0.004	1.62
Average grip strength in both hands (mm Hg)	−0.01	0.002	−8.39	<0.001	12.9
No of damaged joints	0.02	0.01	2.25	0.03	1.01
No of fibromyalgia tender points	0.24	0.02	10.7	<0.001	21.2
PASI	0.007	0.015	0.48	0.63	0.05
Morning stiffness (yes vs no)	2.01	0.25	8.01	<0.001	11.6
ESR (mm/h)	0.03	0.007	3.72	<0.001	3.0
Haemoglobin (g/l)	−0.04	0.009	−4.52	<0.001	4.3
HAQ	2.62	0.16	16.77	<0.001	38.1
SF-36 pain	−0.07	0.004	−16.46	<0.001	36.8
SF-36 mental health	−0.07	0.006	−13.06	<0.001	27.4
NSAID ever (yes vs no)	1.39	0.58	2.39	0.02	1.35
DMARD ever (yes vs no)	0.42	0.26	1.63	0.10	0.5
Immunosuppressives ever (yes vs no)	1.50	0.25	5.97	<0.001	6.7
Methotrexate ever (yes vs no)	1.45	0.25	5.78	<0.001	6.3
Oral steroids ever (yes vs no)	1.46	0.33	4.43	<0.001	3.8

DMARD, disease-modifying antirheumatic drugs; ESR, erythrocyte sedimentation rate; FSS, fatigue severity scale; HAQ, health assessment questionnaire; NSAID, non-steroidal anti-inflammatory drugs; PASI, psoriasis area and severity index; SF-36, medical outcome survey short form 36.