Effects of hydrogen inhalation duration on symptom relief in elderly patients with knee osteoarthritis: A pilot study

Table 1 Demographic and clinical characteristics of subjects by arm in baseline

Variables	Total (n = 49)	LT group (n = 24)	ST group (n = 25)	P value
Age, years, mean (SD)	80.1 (5.8)	80.5 (5.6)	79.6 (6.1)	0.594
Sex, female	38 (77.6)	19 (79.2)	19 (76.0)	0.791
BMI, kg/m2, mean (SD)	23.5 (2.9)	23.3 (2.9)	23.8 (2.9)	0.507
Affected side				0.012
Unilateral	30 (61.2)	5 (20.8)	14 (56.0)
Bilateral	19 (38.8)	19 (79.2)	11 (44.0)
KL grade				0.477
2	25 (51.0)	11 (45.8)	14 (56.0)
3	24 (49.0)	13 (52.4)	11 (44.0)
Duration of KOA, years, median (IQR)	20 (6, 29)	20 (6.3, 30)	20 (6, 20)	0.389
Education level				0.428
High school education or less	8 (16.3)	3 (12.5)	5 (20.0)
College degree	15 (30.4)	6 (25.0)	9 (36.0)
Bachelor degree or above	26 (53.1)	15 (62.5)	11 (44.0)
Cigarette smoking	2 (4.1)	0 (0)	2 (8.0)	-
Alcohol drinking	4 (8.2)	1 (4.2)	3 (12.0)	0.609
Medical history
Respiratory disease	13 (26.5)	4 (16.7)	9 (36.0)	0.125
Hypertension	35 (71.4)	18 (75.0)	17 (68.0)	0.588
Coronary heart disease	19 (38.8)	7 (29.2)	12 (48.0)	0.176
Gastrointestinal disease	11 (22.4)	5 (20.8)	6 (24.0)	0.791
Diabetes mellitus	13 (26.5)	7 (29.2)	6 (24.0)	0.682
Chronic kidney disease	1 (2.0)	1 (4.2)	0 (0)	-
Cancer	4 (8.2)	2 (8.3)	2 (8.3)	1.000
Cerebrovascular disease	11 (22.4)	4 (16.7)	7 (28.0)	0.342
Analgesics taken	73 (60.3)	39 (63.9)	34 (56.7)	0.414
Types of analgesics taken	32 (65.3)	14 (58.3)	18 (72.0)	0.315

Data are expressed as n (%), mean (SD) or median (IQR). BMI: Body mass index; KOA: Knee osteoarthritis; IQR: Interquartile range; LT: Long-term; ST: Short-term; KL: Kellgren-Lawrence.

Table 2 Western Ontario and McMaster Universities Osteoarthritis Index total score, Western Ontario and McMaster Universities Osteoarthritis Index subscale scores, and 36-item Short-Form Health Survey of subjects by arm in baseline

Variables	LT group (n = 24)	ST group (n = 25)	P value
WOMAC, mean (SD)
WOMAC total score	100.3 (22.3)	84.9 (17.8)	0.010
WOMAC pain score	19.0 (5.5)	18.2 (5.3)	0.625
WOMAC stiffness score	9.3 (4.1)	9.0 (3.2)	0.722
WOMAC function score	71.9 (19.5)	57.7 (14.4)	0.005
SF-36, mean (SD)
Physical function	51.0 (12.5)	58.2 (17.4)	0.105
Physical role	52.1 (40.3)	45.0 (40.2)	0.541
Social function	79.2 (15.5)	79.5 (13.9)	0.937
Emotion role	66.7 (40.5)	64.0 (40.7)	0.820
Body pain	42.3 (13.3)	43.3 (10.0)	0.759
Vitality	68.1 (12.2)	65.0 (15.7)	0.443
General health	44.9 (14.6)	46.2 (17.6)	0.776
Mental health	69.7 (12.0)	65.6 (15.7)	0.315

Data are expressed as mean (SD). WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index; LT: Long-term; ST: Short-term; SF-36: 36-item Short-Form Health Survey.

Table 3 Western Ontario and McMaster Universities Osteoarthritis Index total score and Western Ontario and McMaster Universities Osteoarthritis Index subscale scores of subjects by arm in week-12

Variables	LT group (n = 24)	ST group (n = 25)	P value
ΔWOMAC total score	28.2 (7.0)	11.2 (4.6)	< 0.001
ΔWOMAC pain score	8.2 (4.3)	3.6 (3.4)	< 0.001
ΔWOMAC stiffness score	2.4 (2.5)	0.5 (1.2)	0.002
ΔWOMAC function score	17.6 (6.3)	7.4 (4.5)	< 0.001

Data are expressed as mean (SD). WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index; LT: Long-term; ST: Short-term.

Table 4 36-item Short-Form Health Survey of subjects by arm in week-12

Variables	LT group (n = 24)	ST group (n = 25)	P value	Adjust P value
Δ Physical function	26.7 (11.2)	16.3 (12.4)	0.003	0.024
Δ Physical role	39.0 (37.4)	34.9 (37.7)	0.704	0.996
Δ Social function	23.9 (15.2)	17.5 (12.5)	0.110	0.220
Δ Emotion role	21.6 (40.6)	21.5 (39.6)	0.996	0.996
Δ Body pain	27.4 (12.3)	20.9 (10.6)	0.057	0.152
Δ Vitality	12.7 (13.5)	12.1 (14.4)	0.890	0.996
Δ General health	12.0 (11.9)	4.1 (10.9)	0.019	0.076
Δ Mental health	13.4 (12.7)	14.6 (15.1)	0.755	0.996

Data are expressed as mean (SD). LT: Long-term; ST: Short-term; SF-36: 36-item Short-Form Health Survey.