Effects of oral rehydration solution-based prophylactic sodium supplementation on clinical outcomes in pediatric pneumonia: A randomized controlled trial

Table 1 Sociodemographic criteria of the enrolled participants, n (%)

Age (months)
Median (IQR)	4 (8.8)
Min–Max	1-59
Gender distribution
Males	74 (52.9)
Females	66 (47.1)

IQR: Interquartile range; Min: Minimum; Max: Maximum.

Table 2 Clinical criteria of the enrolled participants, n (%)

Hospital length of stay (days)
Median (IQR)	9 (7)
Min-Max	5-35
Na on admission (mmol/L)
Median (IQR)	136 (3)
Min-Max	135-144
Na on day 2 (mmol/L)
Median (IQR)	135 (3)
Min-Max	127-150
Na on day 4 (mmol/L)
Median (IQR)	135 (3)
Min-Max	127-148
Na on discharge (mmol/L)
Median (IQR)	136 (3)
Min-Max	128-148
K on admission (mmol/L)
Median (IQR)	4.9 (1.0)
Min-Max	3.0-6.3
K on day 2 (mmol/L)
Median (IQR)	4.8 (1.2)
Min-Max	3.1-6.5
K on day 4 (mmol/L)
Median (IQR)	5 (1.2)
Min-Max	3.2-6.4
K on discharge (mmol/L)
Median (IQR)	4.8 (1)
Min-Max	2.5-6.1
Modified shock index on admission
Median (IQR)	2 (0.3)
Min-Max	1.4-2.4
Modified shock index on day 4
Median (IQR)	1.8 (0.3)
Min-Max	1.2-2.5
Modified shock index on discharge
Median (IQR)	1.7 (0.4)
Min-Max	1.2-2.7
Respiratory score on admission
Median (IQR)	8 (2)
Min-Max	5-12
Respiratory score on day 4
Median (IQR)	5 (4)
Min-Max	2-12
Fasting time in hours
Median (IQR)	24 (18)
Min-Max	6-48
Weight Z score
Median (IQR)	-1.1 (2.4)
Min-Max	-3.0:2.0
Height Z score
Median (IQR)	-1.1 (1.2)
Min-Max	-3.0:0.8
BMI Z score
Median (IQR)	-0.7 (2.7)
Min-Max	-3.0:3.0
NLR on admission
Median (IQR)	1.3 (1.4)
Min-Max	0.03-27.2
NLR on discharge
Median (IQR)	1.0 (0.9)
Min-Max	0.09-12
PNI on admission
Median (IQR)	62.0 (23.3)
Min-Max	27.5-248
PNI on discharge
Median (IQR)	58.0 (14.7)
Min-Max	29.5-102
PLR on admission
Median (IQR)	81.5 (85.1)
Min-Max	13.3-419
PLR on discharge
Median (IQR)	88.2 (75.2)
Min-Max	11.9-548

BMI: Body mass index; IQR: Interquartile range; K: Potassium; Min: Minimum; Max: Maximum; Na: Sodium; NLR: Neutrophil-lymphocyte ratio; PLR: Platelet-to-lymphocyte ratio; PNI: Prognostic Nutritional Index.

Table 3 Matching between the intervention and control groups, n (%)

	Interventional (n = 70)	Control (n = 70)	P value
Age in months
Median (IQR)	5 (9.5)	4 (4.6)	0.1461
Min-Max	1.3-4.8	1-59
Modified shock index on admission
Median (IQR)	1.9 (0.3)	2.0 (0.3)	0.0511
Min-Max	1.4-2.4	1.5-2.4
Respiratory score on admission
Median (IQR)	8 (2)	8 (2)	0.9511
Min-Max	5-12	5-12
Sodium on admission (mmol/L)
Median (IQR)	136 (2)	137 (3)	0.0611
Min-Max	135-142	135-144
Potassium on admission (mmol/L)
Mean (SD)	4.6 (0.7)	4.9 (0.7)	0.0382,a
Min-Max	3.0-6.0	3.3-6.3
Weight Z score
Median (IQR)	-1.0 (2.16)	-1.2 (2.4)	0.1631
Min-Max	-3.0:2.0	-3.0:1.8
Height Z score
Mean (SD)	-1 (0.7)	-1.1 (0.9)	0.4942
Min-Max	-3.0:0.6	-3.0:0.8
BMI Z score
Median (IQR)	-0.7 (2.5)	-1.1 (2.7)	0.2581
Min-Max	-3.0:3.0	-3.0:2.0
NLR
Median (IQR)	1.0 (1.4)	1.0 (1.8)	0.1981
Min-Max	0.1-27.2	0.03-24
PNI
Median (IQR)	60.0 (20.6)	64.7 (24.0)	0.6941
Min-Max	45-126	27.5-248
PLR
Median (IQR)	84.4 (87.1)	74.8 (84.4)	0.4261
Min-Max	26.6-419	13.3-375.3

¹Mann-Whitney U test.

²Independent t test.

^aP values less than 0.05 were considered significant.

BMI: Body mass index; IQR: Interquartile range; Min: Minimum; Max: Maximum; NLR: Neutrophil-lymphocyte ratio; PLR: Platelet-to-lymphocyte ratio; PNI: Prognostic Nutritional Index.

Table 4 Impact of oral rehydration solution supplementation on hospital outcomes in both groups, n (%)

	Interventional (n = 70)	Control (n = 70)	P value
Na on day 2 (mmol/L)
Median (IQR)	135 (3)	136 (5)	0.7951
Min-Max	131-150	127-143
Na on day 4 (mmol/L)
Median (IQR)	135 (3)	135 (5)	0.4131
Min-Max	129-145	127-148
Na on discharge (mmol/L)
Median (IQR)	137 (3)	135 (4)	0.0021,a
Min-Max	132-141	128-148
K on day 2 (mmol/L)
Mean (SD)	4.7 (0.7)	4.8 (0.7)	0.3722
Min-Max	3.1-6.5	3.4-6.2
K on day 4 (mmol/L)
Median (IQR)	4.9 (1.2)	5.0 (1.2)	0.4691
Min-Max	3.3-6.0	3.2-6.4
K on discharge (mmol/L)
Median (IQR)	4.9 (0.8)	4.8 (1.0)	0.7371
Min-Max	3.5-6.1	2.5-6.0
Modified shock index on day 4
Median (IQR)	1.8 (0.3)	1.8 (0.3)	0.6911
Min-Max	1.2-2.5	1.3-2.4
Respiratory score on day 4
Median (IQR)	4 (2)	6 (4)	0.0011,a
Min-Max	2-12	2-12
Modified shock index on discharge
Median (IQR)	1.8 (0.4)	1.6 (0.4)	0.2951
Min-Max	1.2-2.7	1.2-2.5
Fasting time (hours)
Mean (SD)	23.1 (11.5)	28.2 (12.2)	0.0122,a
Min-Max	6-48	6-48
NLR
Median (IQR)	1.0 (0.5)	0.9 (1.2)	0.9951
Min-Max	0.1- 3.7	0.1- 12
PNI
Median (IQR)	58.7 (17.9)	58 (12.6)	0.6861
Min-Max	29.5-102	39.5-96
PLR
Median (IQR)	92.0 (79.7)	84.4 (69.8)	0.2451
Min-Max	18-548	11.9-301.7

¹Mann-Whitney U test.

²Independent t test.

^aP values less than 0.05 were considered significant.

IQR: Interquartile range; K: Potassium; Min: Minimum; Max: Maximum; Na: Sodium; NLR: Neutrophil-lymphocyte ratio; PLR: Platelet-to-lymphocyte ratio; PNI: Prognostic Nutritional Index.

Table 5 Impact of oral rehydration solution on hospital length of stay, n (%)

	Interventional (n = 70)	Control (n = 70)		P value
Hospital length of stay (days)
Median (IQR)	7 (3)	11 (9)		0.0011,a
Min-Max	5-20	5-35
Hodges-Lehmann median difference
Estimate	Confidence interval
	Upper level		Lower level
4	3		5
Effect size = 0.596

¹Mann-Whitney U test.

^aP values less than 0.05 were considered significant.

IQR: Interquartile range; Min: Minimum; Max: Maximum.

Table 6 Differences in sodium and potassium levels (on discharge–on admission) in the intervention and control groups, n (%)

	Interventional (n = 70)	Control (n = 70)	P value
Differences in sodium and potassium levels (on discharge–on admission)
Difference of Na
Median (IQR)	0 (3.0)	-1.5 (3.2)	< 0.0011,a
Min-Max	-7:5	-12:9
Difference of K
Mean (SD)	0.1 (0.7)	-0.2 (0.8)	0.0132,a
Min-Max	-1.2:1.8	-2.2:1.7
Differences in sodium and potassium levels (on day 4–on admission)
Difference of Na
Median (IQR)	-0.5 (3.2)	-2.0 (5.0)	0.0331,a
Min-Max	-8:10	-12:12
Difference of K
Mean (SD)	0.1 (0.77)	-0.01 (0.78)	0.1182
Min-Max	-2.3:2.5	-1.7:2.3
Differences in sodium and potassium levels (on day 2–on admission)
Difference of Na
Median (IQR)	-1 (2)	-1 (4)	0.0861
Min-Max	-10:14	-11:5
Difference of K
Median (IQR)	0.05 (1)	0 (0.7)	0.4961
Min-Max	-1.4:2.2	-2:1.4

¹Mann-Whitney U test.

²Independent t test.

^aP values less than 0.05 were considered significant.

IQR: Interquartile range; K: Potassium; Min: Minimum; Max: Maximum; Na: Sodium.

Table 7 Mediation analysis for hospital stay to assess the direct effect of oral rehydration solution

The outcome is an improvement in hospital length of stay
Estimate	Std. Error	Z value	aP value	95%CI lower level	95%CI upper level
A: Direct effect of Na supplementation
-3.3	0.54	-6	< 0.001a	-4.4	-2.2
B: Indirect effect: In the presence of mediators
Mediator 1: Respiratory score on day 4
0.423	0.224	-1.8	0.059	-0.86	0.015
Mediator 2: Fasting time
-1.2	0.516	-2.4	0.014a	-2.28	0.26
C: Total effect: Direct + indirect
-5.02	0.792	-6.3	< 0.001a	-6.5	-3.4

^aP values less than 0.05 were considered significant.

Table 8 Regression analysis for hospital length of stay

Hospital length of stay in days
Variable	Univariate analysis			Multivariate analysis
	B	CI	P value	CI	P value
Interventional (ORS) vs control1	-5.09	-6.6:-3.4	< 0.001a	-6.37:-3.4	< 0.001a
Respiratory scores on admission	1.3	0.86:1.9	< 0.001a	0.88:1.84	< 0.001a
Modified shock index on admission	4.5	0.73:8.4	0.02a	-3.9:3.2	0.859
Age in months	-0.18	-0.096:0.06	0.652
Sex2	0.71	-1.07:2.5	0.43
Na on admission	0.032	-0.4:0.4	0.88
K on admission	0.947	-0.28:2.1	0.131	-0.09:1.2	0.786
Weight Z scores	-0.73	-1.4:-0.07	0.03	-5.4:1.9	0.356
Height Z scores	-1.06	-2:-0.04	0.04	-1.87:2.1	0.88
BMI Z scores	-0.4	-1:0.08	0.096	-1.43:3.6	0.387

¹The control group is the reference.

²Female sex is the reference.

^aP values less than 0.05 were considered significant.

BMI: Body mass index; K: Potassium; Na: Sodium; ORS: Oral rehydration solution.

Table 9 Cross-tabulation of Na levels between the studied groups, n (%)

	Interventional (n = 70)	Control (n = 70)	P value
On day 2
Hyponatremia on day 2	38 (54.3)	34 (48.5)	0.491
Normal natremia on day 2	32 (45.7)	36 (51.4)
On day 4
Hyponatremia on day 4	37 (52.8)	35 (50)	0.731
Normal natremia on day 4	33 (47.2)	35 (50)
On discharge
Hyponatremia on discharge	21 (30)	39 (55.7)	0.021,a
Normal natremia on discharge	49 (70)	31 (44.3)

¹χ² test.

^aP values less than 0.05 were considered significant.

Hyponatremia was defined as a serum sodium concentration < 135 mmol/L, and normal natremia was defined as a serum sodium concentration of 135–145 mmol/L.