Intra-rater reliability of the 6-min walk test in people with liver cirrhosis

Table 1 Demographic, anthropometric, and hemodynamic characteristics of participants with liver cirrhosis (n = 20)

Variable	Before 6MWT-1	After 6MWT-1	Before 6MWT-2	After 6MWT-2
Gender (female)	55%
Age (years)	59 ± 11.1
Weight (kg)	81.3 ± 19.7
Height (cm)	143.7 ± 6.21
BMI (kg/m2)	28.5 ± 5.9
Right arm circumference (cm)	30 ± 5.7
Left arm circumference (cm)	29.8 ± 5.7
Waist circumference (cm)	100.4 ± 17.9
SBP (mmHg)	129.0 ± 14.0	140.0 ± 16.9	123.8 ± 9.2	138.8 ± 12.5
DBP (mmHg)	74.0 ± 7.0	86.6 ± 17.0	75.3 ± 4.3	84.1 ± 12.1
MAP (mmHg)	92.0 ± 9.0	104.4 ± 14.6	91.4 ± 5.1	102.3 ± 9.2
HR (bpm)	70 ± 12	98 ± 17	72 ± 14	96 ± 18
SpO2 (%)	98 ± 2	97 ± 2	97 ± 3	97 ± 2
Borg scale	0.6 ± 1.5	7.6 ± 0.5	0.6 ± 1.5	7.5 ± 0.5

Data are presented as mean ± SD. BMI: Body mass index; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; MAP: Mean arterial pressure; HR: Heart rate; SpO₂: Peripheral oxygen saturation; 6MWT-1: First 6-min walk test; 6MWT-2: Second 6-min walk test.

Table 2 Clinical and laboratory data of participants with liver cirrhosis (n = 20)

Variable	Data
Etiology
Alcohol	8
Autoimmune hepatitis	1
Hepatitis C	5
Drug-induced	4
NASH	2
MELD	11 ± 3
CTP
A	19
B	1
Signs1
Ascites	2
Esophageal varices	4
Fatigue	6
Palmar erythema	1
Jaundice	2
Laboratory data
Albumin (g/dL)	3.62 ± 0.55
Total bilirubin (mg/dL)	1.01 ± 0.50
Indirect bilirubin (mg/dL)	0.44 ± 0.16
INR	1.23 ± 0.25
GGT (U/L)	186.67 ± 274.75
AST/SGOT (U/L)	44.79 ± 32.75
ALT/SGPT (U/L)	31.32 ± 19.01
Creatinine (mg/dL)	1.28 ± 1.48

¹Some participants had multiple signs while others showed none. Data are presented as mean ± SD. NASH: Nonalcoholic steatohepatitis; MELD: Model for End-stage Liver Disease; CTP: Child-Turcotte-Pugh; GGT: Gamma-glutamyl transferase; INR: International normalized ratio; AST: Aspartate aminotransferase; SGOT: Serum oxaloacetic transaminase; ALT: Alanine aminotransferase; SGPT: Serum glutamic-pyruvic transaminase.

Table 3 Associated diseases and medications of participants with liver cirrhosis (n = 20)

Variable	Data
Associated diseases1
SAH	14
DM	7
Dyslipidemia	5
Splenomegaly	1
Hypothyroidism	1
Medications2
Beta-blocker	6
Immunosuppressant	1
Angiotensin II receptor antagonist	4
Statin	5
Diuretic	1
Lactulose	1

¹Some participants had more than one associated disease; others had none.

²Some participants were on more than one medication; others were on none. Values are absolute numbers. SAH: Systemic arterial hypertension; DM: Diabetes mellitus.

Table 4 One-sample t-test comparing mean differences in distances walked between the two 6-min walk tests with zero difference

Variable	One-sample t-test compared with the zero constant
	Mean (m)	SD (m)	n	SE (m)	Constant	t-value	df	P value
6MWT-2 - 6MWT-1 (m)	-14.4	26.7	19	6.1	0.0	-2.34714	18	0.03

6MWT-2: Second 6-min walk test; 6MWT-1: First 6-min walk test; df: Degree of freedom; SD: Standard deviation; SE: Standard error.

Table 5 Paired Student’s t-test results for distances walked in two 6-min walk tests

Variables	Paired t-test
	Mean (m)	SD (m)	n	Difference (m)	SE (m)	t	df	P value	95%CI
6MWT-1 (m)	445.6	120.5	19	14.4	26.7	2.347138	18	0.03	1.5-27.2
6MWT-2 (m)	431.3	115.6

6MWT-1: First 6-min walk test; 6MWT-2: Second 6-min walk test; df: Degree of freedom; CI: Confidence interval; SD: Standard deviation; SE: Standard error.

Table 6 Intraclass correlation coefficient (n = 19)

	Intraclass correlation1	95%CI		F test with true value 0
		Lower limit	Upper limit	Value	df1	df2	P value
Single measures	0.9692	0.904	0.989	77.365	18	18	< 0.001
Mean measures	0.9843	0.950	0.994	77.365	18	18	< 0.001

¹Intraclass correlation coefficients (type A) using an absolute agreement definition.

²The estimator is the same whether the interaction effect is present or not.

³This estimate is calculated assuming the interaction effect is absent because it cannot be estimated otherwise. Two-way mixed-effects model where people effects are random and measure effects are fixed. CI: Confidence interval; df: Degree of freedom.