Exploring determinants predicting response to intra-articular hyaluronic acid treatment in symptomatic knee osteoarthritis: 9-year follow-up data from the Osteoarthritis Initiative

Table 5 WOMAC scores and changes—participants with WOMAC pain score^a ≥ 8 at T0

	Total	High,^b WOMAC pain^a ≥ 8
	Responders and nonresponders (n = 112)^c	Responders^d (n = 63)	Nonresponders^e (n = 49)	p value^f	p value^g
WOMAC at T0
	(n = 112)	(n = 63)	(n = 49)
Pain (0–20)	10.44 ± 2.28	10.87 ± 2.37	9.88 ± 2.05	0.008	0.112
	(n = 104)	(n = 62)	(n = 42)
Function (0–68)	29.93 ± 9.43	30.95 ± 8.93	28.41 ± 10.04	0.229	0.223
	(n = 112)	(n = 63)	(n = 49)
Stiffness (0–8)	3.85 ± 1.50	3.87 ± 1.40	3.82 ± 1.64	0.966	0.364
	(n = 104)	(n = 62)	(n = 42)
Total (0–96)	44.24 ± 11.67	45.63 ± 11.07	42.20 ± 12.36	0.146	0.163
WOMAC change (T0 to T1)
	(n = 112)	(n = 63)	(n = 49)
Pain	−2.41 ± 4.06	−5.31 ± 2.84	1.33 ± 1.52	< 0.001	< 0.001
20% ≤ decrease < 40%		59% (37)
Decrease > 40%		41% (26)
	(n = 104)	(n = 62)	(n = 42)
Function	−5.30 ± 14.52	−11.88 ± 10.99	4.42 ± 13.69	< 0.001	< 0.001
20% ≤ decrease < 40%		44% (27)
Decrease > 40%		21% (13)
	(n = 112)	(n = 63)	(n = 49)
Stiffness	−0.16 ± 2.16	−0.75 ± 2.03	0.59 ± 2.10	< 0.010	< 0.001
20% ≤ decrease < 40%		30% (19)
Decrease > 40%		25% (16)
	(n = 104)	(n = 62)	(n = 42)
Total	−8.17 ± 18.97	−17.95 ± 14.13	6.27 ± 15.76	< 0.001	< 0.001
20% ≤ decrease < 40%		44% (27)
Decrease > 40%		27% (17)

Results are shown as mean ± standard deviation or % and number (n) of participants’ IAHA injected knees. Bold data are significant at p < 0.05
T0 visit before IAHA treatment, TI visit after IAHA treatment, IAHA intra-articular hyaluronic acid, WOMAC Western Ontario and McMaster Universities Osteoarthritis Index
^aThe level of pain on WOMAC score was divided into three groups (Low, Moderate, and High) based on tertile analysis: High represents patients in the highest tertile
^bWOMAC Likert 3.1 (scale 0–20) pain scores at T0
^cNumber of injected knees based on 99 participants
^dResponders had a decrease in WOMAC pain score of at least 20% between T0 and T1
^eNonresponders had the same WOMAC pain score or an increase in WOMAC pain score between T0 and T1
^fContinuous variables were compared using Student’s t test/Mann–Whitney test
^gContinuous variables were analyzed using a linear mixed model adjusted for age, sex, and body mass index

ISSN: 1478-6362