Comparison of clinical and biochemical markers of dehydration with the clinical dehydration scale in children: a case comparison trial

Table 3 Comparison of various markers of dehydration in two cohorts

Markers	Dehydrated n = 73	Comparison n = 143	AUC (SE)	P value
Dehydration score	3 (0–8)	0 (0–0)		<0.0001
Pre-hydration systolic blood pressure z-score	0.57 (-0.18-1.54)	0.97 (0.02-1.90)		n.s.
Pre-hydration diastolic blood pressure z-score	0.67 (-0.09-1.21)	0.24 (-0.42, 1.10)		n.s.
Pre-hydration heart rate	134 (112, 158)	97 (84, 130)		<0.0001
Urine Na/K ratio [17]	0.69 (0–4.4)	2.3(0–56)	0.789(0.03)	<0.0001
Serum Osmolality [mOsm] [18]	286 (231–684)	289 (199–391)		0.11
Urine Na [mmol/L] [19]	66.0 ± 55.6	144 ± 74	0.798(0.03)	<0.0001
FeNa [20]	0.19 (0–0.89)	0.52 (0–10.4)	0.753(0.03)	<0.0001
FeUrea [21]	0.398 (0.678-0.96)	0.377 (0.055-4.504)		n.s.
Serum bicarbonate [mmol/L]	20 (10–27)	24 (18–30)	0.821(0.03)	<0.0001
Blood urea [g/L]	5.7 (1.2-41)	5 (2.6-9.2)	0.613(0.05)	0.01
Serum creatinine [μmol/L]	38 (16–408)	45 (3.8-97)	0.666(0.04)	0
Schwartz eGFR [mL/min/1.73 m ² ]	131.6 ± 32.3	136.9 ± 23.2		0.18
Cystatin C [mg/L]	0.67 (0.43-2.89)	0.66 (0.44-1.08)		n.s.
Cystatin C eGFR [mL/min/1.73 m ² ]	144.0 ± 36.9	147.6 ± 25.1		n.s.
Urine osmolality [mOsm]	805 ± 306	876 ± 402		0.2
Urinary microalbumin/creatinine ratio [mg/mmol] [22]	4.4 (0.4-61.1)	2.3 (0.3-9.4)	0.69 (0.04)	<0.0001
Urinary α1-microglobulin/creatinine ratio [mg/mmol] [22]	1.75 (0.30-14.70)	0.70 (0.20-11.30)	0.809(0.04)	P < 0.001

Student’s t-test or Mann Whitney test of established and potential markers of dehydration and acute kidney injury with key references listed. Data are expressed as mean and one standard deviation or median and range, as appropriate based on the distribution. “n.s.” means not significant. Results are expressed as median (range) or mean ± standard deviation where applicable. Urine Na/K ratio, urine Na, FeNa, serum bicarbonate, serum creatinine and blood urea were all significantly different. FeNa = [urine sodium (mmol/L) × plasma creatinine (μmol/L)] / (plasma sodium (mmol/L) ÷ urine creatinine(μmol/L)] × 100. AUC = Receiver operating characteristic curves area under the curves. SE = standard error.

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