Distal esophageal baseline impedance (BI) levels reflect the esophageal mucosal integrity in reflux disease. Systemic sclerosis (SSc) could potentially affect the integrity of esophageal mucosa and consequently impair distal and proximal BI levels, but data in this regard are lacking.
We aimed to prospectively investigate and compare BI levels among non-erosive reflux disease (NERD), SSc patients, and healthy controls (HCs). Consecutive patients with reflux symptoms and well-defined diagnosis of SSc underwent upper endoscopy and, in case of no lesions encountered, manometry and impedance-pH testing off-therapy. In addition to traditional impedance-pH parameters, BI values at 3, 5, 7, and 17cm above the lower esophageal sphincter were calculated.
Fifty-two patients with NERD, 50 with SSc, and 50 HCs were enrolled. Nineteen (38%) SSc patients and 22 (42%) NERD patients had abnormal acid exposure. In patients with SSc, median BI values were significantly lower than in NERD patients and HCs (p < 0.0001) at 3, 5, and 7cm; there was no difference between HCs and NERD patients at 17cm in the proximal esophagus, whereas a significant difference was observed at 17cm between SSc and NERD as well as HCs (p < 0.01).
Distal and proximal BI values in SSc patients were lower than in NERD and HCs, thus we speculated that these findings may be related to the deposition of collagen in the connective tissue. Measurement of BI may be used as an indirect, but simple and accurate marker of esophageal involvement in patients with SSc.