Feasibility of 4 patient-reported outcome measures in a registry setting

Figures & data

Patient flow chart. Each patient had a generic PRO (EQ-5D or SF-12) and a disease-specific PRO (HOOS or OHS) 1–2 years, 5–6 years, or 10–11 years after primary surgery.

Table 1. Patient characteristics of responders and non-responders

Descriptive statistics	Responder	Non-responders	p-value
Population (n)	4,784	963
Percent of total	83	17
Age ^a (median)	73	78	< 0.001
Range (years)	19–102	18–101
18–50 years (%)	5.4	6.0	0.5
50–70 years (%)	36	26	< 0.001
> 70 years (%)	59	68	< 0.001
Female sex (n)	2,750	635
Percent	58	66	< 0.001
Diagnosis (%) ^b
Idiopathic osteoarthritis	84	72	< 0.001
Low-impact fractures	7.9	19	0.01
Childhood diseases	4.3	3.4	0.2
Other arthritis	2.5	4.0	0.8
High-impact injuries	1.0	0.9	< 0.001
Prosthesis design (%)
Uncemented	44	33	< 0.001
Cemented	31	38	< 0.001
Hybrid	25	29	0.03

^a Age of patients on date of sending PRO.

^b Idiopathic OA, other arthritis (rheumatoid arthritis, morbis Bechterew, other arthritis), childhood diseases (congenital hip dislocation, morbis Calvé-Legg-Perthes, epiphysiolysis, acetabular dysplasia), high-impact injuries (fracture of acetabulum, traumatic hip dislocation) and low-impact fractures (fresh fracture of proximal femur, late sequelae from fracture of proximal femur). The diagnosis atraumatic necrosis of the femoral head (2.5%) and other diagnoses (0.6%) are not shown in this table.

Table 2. PRO scores for the total population

PRO	Mean (95% CI)
HOOS (n = 2,365)
HOOS Pain	88 (86–88.8)
HOOS PS	83 (81–84.0)
HOOS QoL	77 (75–78.4)
OHS (n = 2,419)	39 (38–39.6)
SF-12 (n = 2,377)
SF-12 PCS	35 (34–35)
SF-12 MCS	49 (48–50)
EQ-5D (n = 2,407)
EQ-5D Index	0.84 (0.83–0.86)
EQ-VAS	80 (78–81)

Table 3. Overall results

	Specific PROs					Generic PROs
	HOOS n = 2,365			OHS n = 2,419		SF-12 n = 2,377		EQ-5D n = 2,407
	Pain	PS	QoL		P-value	PCS	MCS	EQ-5D Index	EQ-VAS	P-value
Response rate ^a		82		84		83		84
		(81–84)		(83–85)	0.100	(81–84)		(83–85)		0.2
Floor effect ^b	0.1	0.1	0.5	0.0	< 0.001	0.1	0.1	0.0	0.3	0.03
		(0–0.2)	(0–0.3)	(0.3–0.8)		(0–0.3)	(0–0.3)		(0.1–0.5)	0.3
Ceiling effect ^b	37	31	31	20	< 0.001	6.1	6.1	46	12	< 0.001
	(35–39)	(29–33)	(29–32)	(19–22)		(5.1–7.0)	(5.1–7.0)	(44–48)	(11–14)
Proportion of items missing ^c		3.4		1.2	< 0.001	2.3		1.9		0.009
		(3.2–3.5)		(1.0–1.3)		(2.1–2.5)		(1.7–2.2)
Discarded PRO subscales ^b	3.0	2.7	1.9	1.2	< 0.001	2.3	2.3	3.2	5.5	< 0.001
	(2.4–3.7)	(2.1–3.4)	(1.3–2.5)	(0.8–1.7)		(1.7–2.9)	(1.7–2.9)	(2.5–3.9)	(4.6–6.4)
Proportion of items validated ^c		0.9		1.5	< 0.001	0.8		4.3		< 0.001
		(0.8–1.0)		(1.4–1.7)		(0.7–1.0)		(4.0–4.6)
Proportion of PROs requiring manual validation ^a		7.8		7.2	0.4	7.7		22		< 0.001
		(6.7–8.9)		(6.2–8.2)		(6.7–8.8)		(20–23)

Response rate defined as percentage that accepted participation and answered the PROs, out of the total number.

Floor effect defined as percentage with worst possible outcome, out of total number.

Ceiling effect defined as percentage with best possible outcome, out of total number.

^a Percentage of total number of PROs.

^b Percentage of total number of PRO subscales.

^c Percentage of total number of items.

Table 4. Discriminative ability; number of subjects needed per group

	Specific PROs				Generic PROs
	HOOS			OHS	SF-12		EQ-5D
	Pain	PS	QoL		PCS	MCS	EQ-5D Index	EQ-VAS
Diagnoses ^a	116 ^e	57 ^e	115 ^e	80 ^e	51 ^e	75 ^d	107 ^e	56 ^e
Gender	502 ^e	456 ^e	760 ^e	298 ^e	1,886,596	2,736	414 ^e	521 ^e
Prosthesis groups ^b	2,295	645 ^e	10,308	795 ^e	6,471	1,137	1,124 ^d	207 ^e
Age ^c	15,461	814	685 ^d	1,566 ^d	384	361	3,360	270 ^e

^a Idiopathic OA, other arthritis, childhood diseases, high-impact injuries, and low-impact fractures.

^b Hybrid prostheses, cemented and uncemented prostheses.

^c Less than 50 years old, 50–70 years old, and more than 70 years old.

^d p < 0.05.

^e p < 0.001.