Rectal diameter measured by transabdominal ultrasonography for monitoring treatment response in children with functional constipation

Table 1 Demographic data and characteristics of children with functional constipation (n = 44), n (%)/median ± SD/median (interquartile range)

Variables	Total (n = 44)	Group A (RD < 3 cm) (n = 29)	Group B (RD ≥ 3 cm) (n = 15)	P value
Age (months)	50.50 (28.00-92.50)	47 (24.00-93.00)	54 (35.00-60.00)	0.699
Age 6 months to 4 years	21 (47.73)	15 (51.72)	6 (40.00)	0.460
Sex (female)	29 (65.91)	19 (65.52)	10 (66.67)	0.939
Weight (kg)	15.35 (11.60-25.90)	14.60 (11.50-26.30)	16 (12.20-21.40)	0.736
Height (cm)	99.50 (88.50-125.25)	97 (88.00-125.50)	102 (90.00-110.00)	0.755
FC in family	26 (59.09)	18 (62.07)	8 (53.33)	0.576
Previous treatment for FC	20 (45.45)	11 (37.93)	9 (60.00)	0.163
Duration of FC (months)	19.50 (12.00-36.00)	12.00 (12.00-30.00)	24.00 (12.00-40.00)	0.356
Stool frequency at baseline (times per week)	2.13 ± 0.67	2.21 ± 0.73	1.97 ± 0.55	0.268
Stool consistency at baseline (times per week)	2.19 ± 0.82	2.19 ± 0.79	2.20 ± 0.90	0.969
Painful defecation (facial pain score 0-5)	3.61 ± 1.08	3.45 ± 1.07	3.93 ± 1.05	0.159
Bloating or flatulence	11 (25.00)	6 (20.69)	5 (33.33)	0.843
Abdominal pain	12 (27.27)	11 (37.93)	1 (6.67)	0.035
Anal fissure	18 (40.91)	12 (41.38)	6 (40.00)	0.930
Last time of defecation before USG (hour)
Baseline (n = 34)	25.50 (19.00-50.00)	24.00 (19.00-48.00)	30.00 (22.00-54.00)	0.413
Week 1 (n = 43)	20.00 (5.00-30.00)	20.00 (6.00-23.50)	18.50 (4.00-46.00)	0.728
Week 4	18.50 (4.50-23.50)	17.00 (5.00-24.00)	21.00 (4.00-24.00)	0.293
Week 8	19.00 (5.50-23.50)	19.00 (5.00-21.00)	19.00 (6.00-24.00)	0.717
Adequate fiber intake at week 1	5 (11.36)	3 (10.34)	2 (13.33)	0.767
Adequate water intake at week 1	15 (34.09)	9 (31.03)	6 (40.00)	0.552

FC: Functional constipation; USG: Transabdominal ultrasonography; RD: Rectal diameter.

Table 2 Correlations of rectal diameter and anterior wall thickness to baseline variables (n = 44)

Variables	Baseline RD (cm)		Baseline AWT (cm)
	Spearman’s rho	P value	Spearman’s rho	P value
Age (months)	0.22	0.148	0.15	0.337
Weight (cm)	0.19	0.212	0.17	0.263
Height (cm)	0.23	0.139	0.18	0.25
Duration of FC (months)	0.35	0.021	0.25	0.107
Stool frequency at baseline (times per week)	-0.22	0.149	-0.07	0.672
Stool consistency at baseline (BSS 1-7)	-0.09	0.569	-0.01	0.925
Time last defecation to USG (hour)	0.09	0.616	0.003	0.987

AWT: Anterior wall thickness; FC: Functional constipation; RD: Rectal diameter; USG: Transabdominal ultrasonography.

Table 3 Mean of rectal diameter and anterior wall thickness after 8 weeks of treatment

Variables	Mean (95%CI)	Mean change from baseline (95%CI)	P value
Rectal diameter (cm)
Baseline	2.70 (2.51-2.88)
Week 1	2.46 (2.30-2.62)	-0.24 (-0.45 to -0.03)	0.024
Week 4	2.45 (2.30-2.60)	-0.24 (-0.46 to -0.03)	0.025
Week 8	2.33 (2.18-2.48)	-0.37 (-0.59 to -0.14)	0.001
Anterior wall thickness (cm)
Baseline	0.29 (0.27-0.32)
Week 1	0.29 (0.27-0.31)	0.005 (-0.02-0.03)	0.740
Week 4	0.29 (0.27-0.30)	0.003 (-0.03-0.03)	0.865
Week 8	0.29 (0.26-0.30)	-0.004 (-0.03-0.02)	0.997

Table 4 Mean rectal diameter at each visit by baseline rectal diameter group

Variables	Mean (95%CI)	Mean change from baseline (95%CI)	P value
Group A (RD < 3 cm) (n = 29)
Baseline	2.35 (2.17-2.54)
Week 1	2.32 (2.16-2.47)	-0.04 (-0.28-0.21)	0.774
Week 4	2.30 (2.15-2.46)	-0.05 (-0.30-0.19)	0.686
Week 8	2.17 (2.00-2.34)	-0.18 (-0.45-0.08)	0.177
Group B (RD ≥ 3 cm) (n = 15)
Baseline	3.33 (3.10-3.57)
Week 1	2.75 (2.53-2.96)	-0.59 (-0.90 to -0.28)	< 0.001
Week 4	2.73 (2.52-2.95)	-0.60 (-0.93 to -0.28)	< 0.001
Week 8	2.63 (2.39-2.87)	-0.70 (-1.05 to -0.35)	< 0.001

RD: Rectal diameter.