Table 2. Combined pH-Impedance findings.

Data presented as median (interquartile range) unless otherwise stated. SSc – systemic sclerosis.

	SSc	Control	p-value
n	38	38
Acid exposure time, %
Upright	5.9 (1.8 – 20.9)	1.9 (0.6 – 4.6)	0.003
Supine	1.7 (0 – 13.2)	0.1 (0 – 1.1)	0.013
Total	6.8 (2.4 – 18.7)	1.8 (0.5 – 3.8)	<0.001
Longest Acid exposure, minutes
Upright	14.0 (7.1 – 40.2)	4.7 (2.2 – 8.2)	0.001
Supine	11.4 (0 – 41.1)	0.7 (0 – 4.8)	0.017
Total	32.8 (10.9 – 85.7)	6.0 (2.5 – 20.4)	<0.001
Median bolus clearance, seconds
Upright	21.0 (11.3 – 28.0)	13.0 (10.8 – 18.3)	0.015
Supine	14.5 (0 – 30.5)	11.0 (7.0 – 21.5)	0.885
Total	20.5 (11.5 – 28.8)	13.0 (10.0 – 19.0)	0.021
DeMeester Score	27.3 (10.0 – 65.7)	6.0 (1.8 – 13.9)	<0.001
Acid reflux events
Upright	1 (0 – 9)	5 (1 – 21)	0.005
Supine	0 (0 – 1)	1 (0 – 4)	0.125
Total	2 (0 – 10)	8 (2 – 22)	0.011
Weakly acid reflux events
Upright	7 (1 – 16)	17 (10 – 28)	0.003
Supine	2 (0 – 5)	2 (1 – 6)	0.452
Total	10 (2 – 20)	25 (12 – 36)	0.002
Non-acid reflux events
Upright	0 (0 – 1)	0 (0 – 3)	0.172
Supine	0 (0 – 0)	0 (0 – 0)	0.536
Total	0 (0 – 1)	0 (0 – 3)	0.117
Total reflux events	13 (6 – 34)	37 (26 – 54)	0.002
Mean nocturnal baseline impedance, ohms	492 (257 – 915)	2783 (1050 – 3275)	<0.001