Concordance between bio-impedance analysis and clinical score in fluid-status assessment of maintenance haemodialysis patients: A single centre experience

Table 1 Clinical score parameters

Symptoms		Score
Scored as dehydration	Intradialytic hypotension	-1
	Muscle cramps, dizziness or fatigue during current session of dialysis	-1
	Symptomatic dialysis hypotension treated by NaCl (0.9%) infusion	-1
Scored as normohydration	Absence of symptoms given in this table	0
Scored as fluid overload	Hypertension	+1
	SPO2 less than 90%	+1
	Presence of ascites	+1
	Presence of pleural effusion or pulmonary oedema on clinical examination	+1
	Inter dialytic weight gain - per 1 kg gained	+1
	Presence of gallop rhythm	+2
	Dyspnoea based on NYHA class	0 to +3
	Chest radiography features based on stage	+1 to +3
	Oedema (ankles, tibial, graded)	0 to +4

NaCl: Sodium chloride; NYHA: New York Heart Association; SPO₂: Oxygen saturation.

Table 2 Demographic and clinical characteristics of study participants

Characteristic		Statistic
Age (yr)	Median (IQR)	45 (20.5)
Sex	Male, n (%)	46 (57.5)
CKD duration (mo)	Median (IQR)	12.5 (24.5)
Dialysis vintage	Median (IQR)	9 (15)
Blood pressure (mmHg)	Systolic mean ± SD	150 ± 31
	Diastolic mean ± SD	91 ± 19
Body mass index (kg/m2)	Median (IQR)	21.94 (5.13)
Comorbidities	Hypertension, n (%)	41 (51.25)
	Glomerulonephritis, n (%)	22 (27.5)
	Diabetes mellitus, n (%)	14 (17.5)
	Obstructive uropathy, n (%)	8 (10)
	HIV, n (%)	7 (8.75)
	Malignancy, n (%)	2 (2.5)
	Graft failure post-transplant, n (%)	2 (2.5)
	Cystic kidney disease, n (%)	1 (1.25)
Dialysis access	Arterio-venous fistula, n (%)	26 (32.5)
Clinical score	Hypovolemia, n (%)	0 (0.00)
	Normovolemia, n (%)	33 (41.25)
	Hypervolemia, n (%)	47 (58.25)
BIA	Dehydration, n (%)	0 (0.00)
	Normal hydration, n (%)	9 (11.25)
	Fluid overload, n (%)	71 (88.75)
	Mild FO, n (%)	25 (31.25)
	Gross FO, n (%)	46 (57.50)

BIA: Bio-impedance analysis; CKD: Chronic kidney disease; FO: Fluid overload; HIV: Human immunodeficiency virus; IQR: Interquartile range.

Table 3 2-by-2 table assessing association between bio-impedance analysis and the clinical score

		Positive	Negative	Total	P value	95%CI
Clinical score	Positive	45	2	47
	Negative	26	7	33
	Total	71	9	80
McNemar’s Chi Square (20.57)					< 0.0001	0.1758-0.4242

CI: Confidence interval.

Table 4 Univariable analysis of factors associated with fluid overload

Variable	Values	FO+ (n = 71)	FO- (n = 9)	OR	95%CI	P value
Duration of dialysis1 (mo)	3-76	71	9	1.05	0.967-1.147	0.13
No of missed dialysis sessions	0	59	7
	≥ 1	12	2	0.712	0.131-3.856	0.70
Advised on fluid restriction	No	6	2
	Yes	65	7	3.095	0.522-18.357	0.25
Actual fluid intake1 (mL)	200-2800	71	9	0.998	0.997-1.000	0.082
Advised on salt intake	No	9	1
	Yes	62	8	0.8611	0.096-7.719	0.89
Number of anti-hypertensives used	0	11	0
	1	13	2
	2	23	3
	3	14	4
	4	7	0
	5	2	0
	6	1	0	0.903	0.537-1.517	0.70
Patient’s BMI1 (kg/m2)	15.82-32.53	71	9	1.196	0.942-1.520	0.11

¹Variables eligible for inclusion in the multivariable model at a liberal P value of 0.20.

BMI: Body mass index; CI: Confidence interval; FO+: Positive fluid overload; FO-: Negative fluid overload; OR: Odds ratio.

Table 5 Multivariable analysis of factors associated with fluid overload

Variable	Values	OR	95%CI	P value
Duration of dialysis (mo)	3-76	1.054	0.962-1.154	0.258a
Actual fluid intake (mL)	200-2800	0.999	0.997-1.000	0.099a
BMI (kg/m2)	15.82-32.53	1.191	0.934-1.519	0.159a

^aP values are non-significant.

BMI: Body mass index; CI: Confidence interval; OR: Odds ratio.