Disagreement between symptom-reflux association analysis parameters in pediatric gastroesophageal reflux disease investigation

Table 1 Characteristics of the registered reflux and symptom episodes

	GER episodes	Irritability episodes	Cough episodes
Min	22	2	1
Max	141	82	19
Median	67	11	5
IQR	48	18	10
Sum	1692	421	155

GER: Gastroesophageal reflux; Min: Minimal number for a single patient; Max: Maximal number for a single patient; Median: Median value for all patients; IQR: Interquartile range.

Table 2 Categorization of SI, SSI and SAP

SI	SSI	SAP	Number of infants	Percent	Cumulative frequency	Cumulative percent
Irritability/reflux association
Abnormal	Abnormal	Abnormal	1	4.35	1	4.35
Abnormal	Abnormal	Normal	2	8.7	3	13.04
Abnormal	Normal	Abnormal	1	4.35	4	17.39
Abnormal	Normal	Normal	4	17.39	8	34.78
Normal	Abnormal	Abnormal	1	4.35	9	39.13
Normal	Abnormal	Normal	1	4.35	10	43.48
Normal	Normal	Normal	13	56.52	23	100
Cough/reflux association
Abnormal	Abnormal	Abnormal	1	4.35	1	4.35
Abnormal	Abnormal	Normal	1	4.35	2	8.7
Abnormal	Normal	Normal	11	47.83	13	56.52
Normal	Normal	Normal	10	43.48	23	100

SI: Symptom index, abnormal if SI≥50%; SSI: Symptom sensitivity index, abnormal if SSI≥10%; SAP: Symptom association probability, abnormal if SAP≥95%.

Table 3 Correlations between SI, SSI and SAP for the irritability/reflux association and the cough/reflux association expressed in Kendall’s tau b

	Irritability			Cough
	SI	SSI	SAP	SI	SSI	SAP
SI	-	0.37102 (P = 0.0147)	0.36011 (P = 0.0225)	-	0.32725 (P = 0.0362)	0.20959 (P = 0.2117)
SSI	0.37102 (P = 0.0147)	-	0.23623 (P = 0.1297)	0.32725 (P = 0.0362)	-	0.29632 (P = 0.0701)
SAP	0.36011 (P = 0.0225)	0.23623 (P = 0.1297)	-	0.20959 (P = 0.2117)	0.29632 (P = 0.0701)	-