Validated repeatability of patient-reported outcome measures following primary total hip replacement: a mode of delivery comparison study with randomized sequencing

Figures & data

Table 1. Randomization sequence

Group 1	Group 2	Group 3	Group 4
Time point 1 in clinic
1. Self-administered	1. Face-to-face	1. Self-administered	1. Face-to-face
2. Face-to-face	2. Self-administered	2. Face-to-face	2. Self-administered
Time point 2
Telephone interview	Postal	Postal	Telephone interview
Time point 3
Postal	Telephone interview	Telephone interview	Postal

Table 2. Missing data. Values are frequency

	Face-to-face			Self-administered			Telephone			Postal
	Pts	Items	Excluded	Pts	Items	Excluded	Items	Pts	Excluded	Pts	Items	Excluded
WOMAC stiffness	0	0	0	0	0	0	1	1	0	1	2	1
WOMAC pain	0	0	0	0	0	0	0	0	0	0	0	0
WOMAC function	2	6	1	2	6	1	4	5	0	3	6	0
OHS	2	13	1	4	23	3	1	1	0	1	12	1
EQ5D	0	0	0	0	0	0	0	0	0	1	1	1
SAPS	0	0	0	0	0	0	0	0	0	0	0	0

Pts: participants

Table 2. Continued

	SI—P				SI—T				P—T
Model	dif.	SE	95% CI	p-value	dif.	SE	95%CI	p-value	dif.	SE	95% CI	p-value
WOMAC Stiffness
1	0.60	2.1	(–3.6 to 4.8)	0.8	5.95	1.8	(2.3 to 9.6)	0.002	4.62	1.5	(1.7 to 7.6)	0.003
2	–0.83	1.8	(–4.3 to 2.7)	0.6	5.28	1.6	(2.0 to 8.6)	0.002	4.94	1.6	(1.8 to 8.1)	0.003
3	–4.19	2.1	(–8.4 to 0.001)	0.05	5.87	2.5	(0.9–11)	0.002	3.04	2.1	(–1.1 to 7.2)	0.1
WOMAC Pain
1	1.58	1.0	(–0.36 to 3.5)	0.1	1.62	1.2	(–0.73 to 4.0)	0.2	0.71	0.8	(–0.91 to 2.3)	0.4
2	1.31	1.0	(–0.66 to 3.3)	0.2	1.78	1.3	(–0.77 to 4.3)	0.2	0.42	0.8	(–1.2 to 2.0)	0.6
3	0.45	1.2	(–2.0 to 3.0)	0.7	1.66	2.0	(–2.3 to 5.6)	0.4	0.30	1.1	(–1.9 to 2.5)	0.8
WOMAC Function
1	0.81	1.6	(–2.4 to 4.1)	0.6	3.15	1.5	(0.21 to 6.1)	0.04	2.61	1.3	(0.11 to 5.1)	0.04
2	–0.07	1.4	(–3.0 to 2.8)	1	2.69	1.4	(–0.06 to 5.4)	0.06	2.62	1.3	(–0.02 to 5.3)	0.05
3	–0.24	1.8	(–3.9 to 3.4)	0.9	2.72	2.1	(–1.5 to 6.9)	0.2	2.11	1.8	(–1.1 to 5.6)	0.2
OHS
1	0.96	1.0	(–1.1 to 3.0)	0.4	–0.69	1.0	(–2.6 to 1.3)	0.5	–1.71	0.44	(–2.6 to –0.83)	<0.001
2	1.06	1.0	(–1.0 to 3.1)	0.2	–0.63	1.0	(–2.8 to 1.5)	0.6	–1.81	0.46	(–2.7 to –0.88)	<0.001
3	0.96	1.3	(–1.6 to 3.6)	0.5	–0.29	1.7	(–3.6 to 3.1)	0.9	–1.24	0.59	(–2.4 to –0.07)	0.04
EQ5D index
1	–0.01	0.02	(–0.06 to 0.03)	0.6	–0.04	0.02	(–0.09 to 0.01)	0.1	–0.02	0.02	(–0.06 to 0.02)	0.5
2	–0.02	0.02	(–0.06 to 0.01)	<0.001	–0.05	0.03	(–0.10 to –0.001)	0.05	–0.02	0.02	(–0.07 to 0.02)	0.3
3	–0.02	0.03	(–0.07 to 0.03)	0.4	–0.05	0.04	(–0.13 to 0.03)	0.2	0.00	0.03	(–0.06 to 0.06)	1.0
SAPS
1	–3.77	0.93	(–5.6 to –1.9)	<0.001	–4.90	0.95	(–6.8 to –3.0)	<0.001	–0.30	0.57	(–1.4 to 0.84)	0.6
2	–3.69	0.92	(–5.5 to –1.9)	0.002	–4.77	1.0	(–6.8 to –2.7)	<0.001	–0.21	0.60	(–1.4 to 1.0)	0.7
3	–4.10	1.2	(–6.4 to –1.8)	0.001	–5.28	1.5	(–8.3 to –2.2)	0.001	0.09	0.81	(–1.5 to 1.7)	0.9

Model 1 = Individual paired differences (IPD), Model 2 = IPD + time delay, Model 3= IPD + time delay + age.

F2F: face to face in clinic; SI: Self-administered in clinic; P: postal; T: telephone interview.

Dif: Individual paired difference: 95% CI: 95% confidence interval.

Table 3. Mean differences by mode. Values are mean (standard deviation)

PROM	Face-to-face	Self-administered	Postal	Telephone	F test
WOMAC stiffness	15.9 (22)	15.5 (22)	13.3 (16)	9.1 (15)	P F (3, 259) = 0.2
WOMAC pain	12.1 (17)	12.1 (17)	10.2 (16)	10.1 (16)	P F (3, 260) = 0.8
WOMAC function	15.4 (19)	15.4 (19)	14.1 (18)	12.1 (16)	P F (3, 260) = 0.7
OHS	39.8 (10)	40.2 (10)	40.1 (9.8)	42.0 (7.7)	P F (3, 258) = 0.6
EQ5D index	0.74 (0.30)	0.74 (0.30)	0.77 (0.30)	0.77 (0.24)	P F (3, 259) = 0.8
SAPS	93.4 (8.7)	89.2 (16)	93.6 (14)	94.3 (13)	P F (3, 260) = 0.09

Table 4. Individual paired differences by mode

F2F—SI					F2F—P				F2F—T
Model	dif.	SE	95% CI	p-value	dif.	SE	95%CI	p-value	dif.	SE	95% CI	p-value
WOMAC Stiffness
1	0				0.60	2.1	(–3.6 to 4.8)	0.8	5.95	1.8	(2.3 to 9.6)	0.002
2	0				–0.83	1.8	(–4.3 to 2.7)	0.6	5.28	1.6	(2.0 to 8.6)	0.002
3	0				13.5	5.6	(2.2 to 25)	0.02	5.87	2.5	(0.9 to 11)	0.02
WOMAC Pain
1	0				1.59	1.0	(–0.36 to 3.5)	0.1	1.61	1.0	(–0.35 to 3.5)	0.1
2	0				1.31	1.0	(–0.66 to 3.3)	0.2	1.78	1.3	(–0.77 to 4.3)	0.2
3	0				4.91	3.3	(–1.7 to 12)	0.1	1.66	2.0	(–2.3 to 5.6)	0.4
WOMAC Function
1	0				0.81	1.6	(–2.4 to4.1)	0.6	3.15	1.5	(0.21 to 6.1)	0.04
2	0				–0.07	1.4	(–3.0 to 2.8)	1	2.69	1.4	(–0.06 to 5.4)	0.06
3	0				0.54	4.9	(–9.2 to 10)	0.9	2.72	2.1	(–1.5 to 6.9)	0.2
OHS
1	–1.41	1.6	(–4.7 to 1.8)	0.4	–1.18	1.2	(–3.5 to 1.2)	0.3	–2.20	1.1	(–4.5 to 0.08)	0.06
2	–1.41	1.6	(–4.6 to 1.8)	0.4	–1.09	1.2	(–3.5 to 1.3)	0.4	–2.26	1.3	(–4.8 to 0.24)	0.08
3	–1.40	1.6	(–4.6 to 1.8)	0.4	5.34	3.9	(–2.5 to 13)	0.2	–7.35	1.7	(–11 to –4)	<0.001
EQ5D index
1	0				–0.01	0.02	(–0.06 to 0.03)	0.6	–0.04	0.02	(–0.09 to 0.01)	0.1
2	0				–0.02	0.02	(–0.06 to 0.01)	0.2	–0.05	0.03	(–0.1 to –0.001)	0.05
3	0				–0.03	0.07	(–0.17 to 0.10)	0.6	–0.05	0.04	(–0.13 to 0.03)	0.2
SAPS
1	4.29	1.8	(0.80 to 7.8)	0.02	0.20	1.4	(–2.6 to 3.0)	0.9	–0.48	1.4	(–3.2 – 2.3)	0.7
2	4.30	1.7	(0.80 to 7.8)	0.02	–0.10	1.4	(–2.9 to 2.7)	0.9	0.11	1.5	(–2.8 to 3.0)	0.9
3	4.26	17	(0.77 to 7.7)	0.02	–4.26	4.7	(–14 to 5.2)	0.4	–2.10	2.2	(–6.5 to 2.3)	0.4

Model 1 = Individual paired differences (IPD), Model 2 = IPD + time delay, Model 3= IPD + time delay + age.

F2F: face to face in clinic; SI: Self-administered in clinic; P: postal; T: telephone interview.

Dif: Individual paired difference: 95% CI: 95% confidence interval.