Table 5.

Independent t test

	BASDAI							Peripheral arthritis
	Low disease activity [< 4] (n = 135)		High disease activity [≥ 4] (n = 85)		P	Mean difference	95% CI	No (n = 133)		Yes (n = 87)		P	Mean difference	95% CI
	Mean	SD	Mean	SD				Mean	SD	Mean	SD
ODI score	12.0	10.7	30.5	15.6	< 0.001*	− 18.4	(− 21.9, − 14.9)	17.8	15.0	21.2	16.5	0.112	−3.4	(−7.7, 0.8)
HADS score
Depression	4.1	3.4	6.4	3.7	< 0.001*	− 2.3	(− 3.3, − 1.3)	5.0	3.1	5.0	4.4	0.938	0.0	(−1.1, 1.0)
Anxiety	4.9	3.5	7.4	3.6	< 0.001*	− 2.5	(− 3.5, − 1.5)	5.9	3.6	5.8	3.9	0.934	0.0	(−1.0, 1.1)
Total	8.9	6.3	13.8	6.7	< 0.001*	− 4.9	(− 6.7, − 3.0)	10.8	6.2	10.8	7.9	0.952	0.1	(−1.9, 2.0)
EQ-5D VAS score	68.1	17.6	54.4	17.9	< 0.001*	13.7	(8.8, 18.5)	63.2	19.4	62.4	18.2	0.764	0.8	(−4.4, 5.9)
EQ-5D-5 L score	0.874	0.122	0.656	0.206	< 0.001*	0.2	(0.2, 0.3)	0.807	0.179	0.763	0.207	0.097	0.0	(0.0, 0.1)
BASFI	1.3	1.5	3.6	2.4	< 0.001*	− 2.3	(− 2.8, − 1.8)	2.0	2.1	2.5	2.3	0.128	−0.5	(− 1.1, 0.1)
BASMI	3.8	1.6	4.2	1.5	0.058	− 0.4	(−  0.8, 0.0)	4.0	1.5	4.0	1.7	0.957	0.0	(− 0.4, 0.4)
SF-36
Physical functioning	81.2	17.1	61.2	19.7	< 0.001*	20.0	(14.2, 25.9)	75.1	21.8	73.0	18.3	0.515	2.1	(−4.3, 8.5)
Role physical	78.0	20.1	57.1	23.2	< 0.001*	20.9	(14.0, 27.8)	72.8	22.8	67.9	24.0	0.192	4.8	(−2.5, 12.1)
Role emotional	80.4	21.3	57.7	25.8	< 0.001*	22.7	(15.2, 30.1)	72.8	24.6	72.0	26.4	0.838	0.8	(−7.1, 8.8)
Vitality	58.7	18.8	41.4	16.4	< 0.001*	17.3	(11.4, 23.1)	51.9	19.5	53.8	20.1	0.551	−1.9	(−8.0, 4.3)
Emotional well-being	70.3	16.4	61.1	18.2	0.001*	9.2	(3.7, 14.8)	67.3	16.7	66.7	18.8	0.839	0.6	(− 5.0, 6.1)
Social functioning	83.8	18.4	65.2	23.1	< 0.001*	18.7	(12.1, 25.2)	77.3	23.0	77.5	20.6	0.943	−0.3	(−7.2, 6.7)
Bodily pain	71.7	18.3	43.7	17.0	< 0.001*	28.1	(22.3, 33.9)	63.8	22.9	59.2	21.3	0.191	4.6	(−2.3, 11.6)
General health	47.7	18.9	31.2	17.7	< 0.001*	16.5	(10.4, 22.7)	40.7	19.7	43.9	20.5	0.333	−3.1	(−9.6, 3.3)
PCS	47.5	6.6	37.9	7.4	< 0.001*	9.6	(7.3, 11.9)	44.7	8.7	43.5	7.5	0.349	1.3	(−1.4, 3.9)
MCS	47.9	9.4	41.0	11.5	< 0.001*	6.8	(3.5, 10.2)	45.1	10.3	46.0	11.2	0.625	−0.8	(−4.3, 2.6)
BASDAI	2.2	1.0	5.7	1.2	< 0.001*	− 3.5	(− 3.8, − 3.2)	3.4	2.1	3.7	2.0	0.316	−0.3	(−0.8, 0.3)
ASDAS-CRP	1.1	0.7	2.5	0.8	< 0.001*	− 1.5	(− 1.7, − 1.3)	1.6	1.0	1.7	1.1	0.563	− 0.1	(−  0.4, 0.2)
	Dactylitis							Uveitis
	No (n = 211)		Yes (n = 8)		P	Mean difference	95% CI	No (n = 140)		Yes (n = 79)		P	Mean difference	95% CI
	Mean	SD	Mean	SD				Mean	SD	Mean	SD
ODI score	18.9	15.5	25.4	18.9	0.248	− 6.5	(− 17.7, 4.6)	18.7	16.0	19.8	15.0	0.601	− 1.2	(−5.5, 3.2)
HADS score
Depression	5.0	3.7	5.6	2.0	0.622	− 0.7	(− 3.2, 1.9)	4.9	3.6	5.1	3.9	0.697	−  0.2	(−1.3, 0.8)
Anxiety	5.9	3.7	6.4	4.0	0.697	− 0.5	(− 3.2, 2.1)	5.9	3.7	5.8	3.8	0.819	0.1	(−1.0, 1.2)
Total	10.8	6.9	12.0	5.5	0.633	− 1.2	(− 6.1, 3.7)	10.8	6.7	10.9	7.3	0.917	− 0.1	(−2.1, 1.9)
EQ-5D VAS score	63.3	18.9	55.3	17.2	0.240	8.0	(− 5.4, 21.4)	64.6	17.7	59.5	20.6	0.056	5.1	(−0.1, 10.3)
EQ-5D-5 L score	0.792	0.192	0.697	0.162	0.168	0.1	(0.0, 0.2)	0.794	0.194	0.779	0.188	0.583	0.0	(0.0, 0.1)
BASFI	2.1	2.1	2.9	3.0	0.331	− 0.8	(− 2.3, 0.8)	2.1	2.2	2.4	2.1	0.257	− 0.3	(−1.0, 0.3)
BASMI	3.9	1.5	5.0	2.2	0.068	− 1.0	(− 2.1, 0.1)	3.7	1.5	4.5	1.6	< 0.001*	− 0.7	(−1.2, − 0.3)
SF-36
Physical functioning	74.7	19.9	63.3	31.3	0.182	11.3	(− 5.4, 28.1)	75.1	20.7	72.5	19.9	0.434	2.6	(−4.0, 9.3)
Role physical	71.0	23.6	65.6	20.4	0.587	5.3	(− 14.0, 24.6)	72.1	22.9	68.3	24.5	0.330	3.8	(−3.9, 11.4)
Role emotional	72.1	25.5	77.8	20.9	0.592	− 5.7	(− 26.5, 15.2)	73.8	24.7	69.6	26.4	0.312	4.2	(−4.0, 12.4)
Vitality	52.7	20.0	52.1	15.1	0.938	0.6	(− 15.7, 17.0)	53.0	19.9	52.4	19.6	0.863	0.6	(−5.9, 7.0)
Emotional well-being	67.2	17.7	59.2	14.3	0.272	8.1	(− 6.4, 22.5)	66.9	18.1	67.6	16.7	0.807	−0.7	(−6.4, 5.0)
Social functioning	77.4	22.1	72.9	20.0	0.624	4.5	(− 13.6, 22.6)	76.7	22.8	78.3	20.4	0.645	−1.7	(−8.9, 5.5)
Bodily pain	61.9	22.0	55.8	26.6	0.515	6.0	(− 12.2, 24.3)	61.8	23.5	62.1	20.4	0.930	− 0.3	(−7.6, 7.0)
General health	42.2	20.2	38.3	19.4	0.649	3.8	(− 12.8, 20.4)	42.3	19.7	41.5	21.1	0.808	0.8	(−5.9, 7.5)
PCS	44.3	8.1	40.9	11.4	0.325	3.4	(− 3.4, 10.2)	44.6	8.5	43.5	7.9	0.460	1.0	(−1.7, 3.8)
MCS	45.4	10.8	45.3	6.8	0.974	0.1	(−  8.6, 8.9)	45.7	11.0	45.2	10.1	0.770	0.5	(−3.0, 4.1)
BASDAI	3.5	2.0	4.2	2.0	0.327	− 0.7	(− 2.2, 0.7)	3.5	2.1	3.5	1.9	0.845	0.1	(−0.5, 0.6)
ASDAS-CRP	1.6	1.0	2.0	1.2	0.270	− 0.4	(− 1.1, 0.3)	1.6	1.0	1.7	1.1	0.393	− 0.1	(−0.4, 0.2)
	Psoriasis							Any back pain
	No (n = 187)		Yes (n = 33)		P	Mean difference	95% CI	No (n = 94)		Yes (n = 126)		P	Mean difference	95% CI
	Mean	SD	Mean	SD				Mean	SD	Mean	SD
ODI score	18.8	15.4	21.1	17.4	0.435	− 2.3	(− 8.1, 3.5)	15.1	15.7	19.4	15.7	0.245	− 4.3	(−11.6, 3.0)
HADS score
Depression	4.8	3.5	6.0	4.1	0.079	− 1.2	(− 2.6, 0.1)	4.4	3.7	5.0	3.7	0.449	−0.7	(−2.4, 1.0)
Anxiety	5.7	3.7	6.4	3.9	0.357	− 0.7	(− 2.0, 0.7)	5.1	3.7	6.0	3.7	0.332	− 0.9	(−2.6, 0.9)
Total	10.5	6.8	12.4	7.5	0.150	− 1.9	(− 4.5, 0.7)	9.5	6.9	10.9	7.0	0.361	− 1.5	(−4.7, 1.7)
EQ-5D VAS score	62.9	19.2	62.8	17.1	0.975	0.1	(− 6.9, 7.2)	66.9	17.4	62.3	19.1	0.312	4.5	(−4.3, 13.3)
EQ-5D-5 L score	0.794	0.185	0.765	0.224	0.425	0.0	(0.0, 0.1)	0.813	0.180	0.788	0.193	0.576	0.0	(−0.1, 0.1)
BASFI	2.2	2.2	2.2	2.4	0.961	0.0	(− 0.8, 0.8)	1.8	2.9	2.2	2.1	0.416	−0.4	(−1.4, 0.6)
BASMI	4.0	1.6	3.7	1.3	0.269	0.3	(− 0.3, 0.9)	3.7	1.6	4.0	1.6	0.414	−0.3	(−1.0, 0.4)
SF-36
Physical functioning	74.6	20.2	72.4	21.5	0.618	2.1	(− 6.3, 10.6)	74.7	26.9	74.1	19.8	0.918	0.6	(−10.2, 11.3)
Role physical	71.5	23.4	67.0	23.7	0.354	4.5	(− 5.1, 14.1)	71.1	27.8	70.7	23.2	0.956	0.3	(−12.0, 12.7)
Role emotional	72.7	25.4	71.7	25.4	0.861	0.9	(− 9.5, 11.3)	71.9	32.9	72.5	24.6	0.932	−0.6	(−13.9, 12.7)
Vitality	52.9	20.0	51.6	18.8	0.742	1.4	(− 6.8, 9.5)	58.2	18.9	52.0	19.9	0.239	6.2	(−4.1, 16.5)
Emotional well-being	67.5	17.5	64.6	18.1	0.438	2.9	(− 4.4, 10.2)	69.7	22.9	66.8	17.0	0.539	2.9	(−6.3, 12.1)
Social functioning	78.5	21.8	72.3	22.4	0.180	6.1	(− 2.9, 15.1)	78.1	27.2	76.9	21.5	0.837	1.2	(−10.3, 12.7)
Bodily pain	61.6	22.2	63.3	23.3	0.709	− 1.8	(− 11.1, 7.6)	69.7	24.4	61.0	22.2	0.158	8.6	(−3.4, 20.7)
General health	42.5	20.1	39.8	19.9	0.537	2.7	(− 5.9, 11.2)	50.7	20.3	40.9	20.0	0.075	9.8	(−1.0, 20.5)
PCS	44.3	8.3	43.5	8.3	0.657	0.8	(− 2.8, 4.4)	46.5	8.1	43.9	8.3	0.249	2.6	(−1.9, 7.1)
MCS	45.7	10.7	44.6	10.5	0.648	1.1	(− 3.6, 5.8)	47.4	13.6	45.2	10.4	0.468	2.1	(−3.7, 7.9)
BASDAI	3.6	2.0	3.3	2.1	0.532	0.2	(− 0.5, 1.0)	2.6	1.7	3.6	2.0	0.036*	− 1.0	(−1.9, −0.1)
ASDAS-CRP	1.7	1.0	1.4	1.0	0.171	0.3	(− 0.1, 0.6)	1.3	1.0	1.7	1.0	0.085	− 0.4	(−0.9, 0.1)
	Current back pain							Spinal pain in the past week
	No (n = 94)		Yes (n = 126)		P	Mean difference	95% CI	No (n = 94)		Yes (n = 126)		P	Mean difference	95% CI
	Mean	SD	Mean	SD				Mean	SD	Mean	SD
ODI score	10.3	12.9	21.7	15.5	< 0.001*	− 11.5	(− 16.2, − 6.7)	5.6	8.0	20.7	15.6	< 0.001*	− 15.1	(−21.6, −8.6)
HADS score
Depression	3.4	2.9	5.4	3.8	< 0.001*	− 2.0	(− 3.2, − 0.9)	3.3	2.5	5.2	3.7	0.020*	− 1.9	(−3.5, − 0.3)
Anxiety	4.9	3.6	6.2	3.7	0.045*	− 1.2	(− 2.4, 0.0)	3.9	3.3	6.1	3.7	0.008*	−2.2	(−3.8, −0.6)
Total	8.3	5.8	11.6	7.1	0.004*	− 3.2	(− 5.4, − 1.0)	7.3	5.1	11.3	7.0	0.009*	− 4.0	(−7.0, −1.0)
EQ-5D VAS score	72.1	13.8	59.9	19.5	< 0.001*	12.2	(6.4, 18.0)	74.7	13.3	61.5	19.0	0.001*	13.2	(5.2, 21.3)
EQ-5D-5 L score	0.886	0.132	0.761	0.198	< 0.001*	0.1	(0.1, 0.2)	0.932	0.110	0.773	0.192	< 0.001*	0.2	(0.1, 0.2)
BASFI	1.2	1.8	2.5	2.2	< 0.001*	− 1.4	(− 2.0, − 0.7)	0.8	1.8	2.4	2.2	< 0.001*	− 1.6	(−2.6, − 0.7)
BASMI	3.7	1.6	4.1	1.6	0.112	− 0.4	(− 0.9, 0.1)	3.6	1.2	4.0	1.6	0.269	− 0.4	(−1.1, 0.3)
SF-36
Physical functioning	82.7	20.8	71.1	19.6	0.001*	11.6	(4.5, 18.7)	87.9	19.3	72.9	20.0	0.008*	15.0	(3.9, 26.0)
Role physical	80.2	23.3	67.4	22.9	0.002*	12.8	(4.6, 20.9)	86.6	18.6	69.2	23.3	0.007*	17.4	(4.7, 30.1)
Role emotional	81.2	27.2	69.3	24.2	0.009*	11.9	(3.0, 20.7)	88.1	22.8	71.0	25.1	0.015*	17.1	(3.3, 30.8)
Vitality	62.4	17.5	49.2	19.5	< 0.001*	13.1	(6.4, 19.9)	62.9	13.5	51.7	20.0	0.042*	11.2	(0.4, 22.0)
Emotional well-being	70.5	17.9	65.9	17.5	0.155	4.6	(− 1.7, 10.9)	75.7	16.2	66.2	17.6	0.053	9.5	(−0.1, 19.1)
Social functioning	86.9	19.3	73.5	21.9	< 0.001*	13.4	(5.8, 21.0)	92.0	16.0	76.0	22.0	0.009*	16.0	(4.0, 27.9)
Bodily pain	79.1	18.2	55.8	20.7	< 0.001*	23.3	(16.1, 30.5)	91.7	11.8	59.3	21.1	< 0.001*	32.5	(20.7, 44.2)
General health	48.3	20.1	39.6	19.8	0.019*	8.6	(1.4, 15.9)	54.6	12.8	40.9	20.2	0.018*	13.7	(2.4, 25.0)
PCS	49.1	7.7	42.5	7.9	< 0.001*	6.7	(3.8, 9.5)	52.5	4.4	43.4	8.1	< 0.001*	9.0	(4.5, 13.6)
MCS	48.5	10.1	44.4	10.8	0.037*	4.1	(0.2, 8.0)	52.1	8.0	44.9	10.7	0.019*	7.2	(1.2, 13.2)
BASDAI	2.0	1.3	4.0	2.0	< 0.001*	− 2.0	(− 2.6, − 1.5)	1.1	0.9	3.8	1.9	< 0.001*	−2.7	(−3.5, −1.9)
ASDAS-CRP	0.9	0.8	1.9	1.0	< 0.001*	− 1.0	(− 1.3, − 0.7)	0.6	0.6	1.8	1.0	< 0.001*	−1.1	(−1.5, −0.7)

*Significant difference (P < 0.05)