Response of eosinophilic oesophagitis to proton pump inhibitors is associated with impedance‐pH parameters implying anti‐reflux mechanism of action

SummaryBackgroundProton pump inhibitors (PPIs) are effective therapies for eosinophilic oesophagitis (EoE), but the mechanism of action is uncertain. At on‐PPI impedance‐pH monitoring, improvement in oesophageal chemical clearance assessed with post‐reflux swallow‐induced peristaltic wave (PSPW) index characterises PPI‐responsive EoE and reflux disease. Off‐PPI, higher efficacy of the oesophago‐salivary reflex as measured with PSPW‐associated pH increments characterises PPI‐responsive reflux disease and could typify PPI‐responsive EoE as well.AimTo establish whether PPI responsiveness in EoE is associated with higher efficacy of the oesophago‐salivary reflex.MethodsProspective multicentre study in EoE patients investigated with impedance‐pH monitoring before starting PPI. Impedance‐pH parameters in PPI‐responsive and PPI‐refractory cases were compared. PPI response was defined histologically.ResultsConsiderable PSPW‐associated pH increments (median 1.4 units) were found in 80 EoE patients, with significantly higher values in 48 PPI‐responsive than in 32 PPI‐refractory cases (1.8 vs 1.0, P = 0.02). Mucosal integrity, as measured with mean nocturnal baseline impedance was more severely impaired in the distal oesophagus in PPI‐responsive cases, the gradient between mid and distal oesophagus being significantly higher (546 vs 137 Ω, P = 0.0002). PSPW‐associated pH increments and the baseline impedance gradient between mid and distal oesophagus were independently associated with histological response at multivariable logistic regression; at receiver operating characteristic analysis, the area under the curve of PPI response calculated by combined assessment was 0.88.ConclusionHigher efficacy of oesophago‐salivary reflex and more severe mucosal damage in the distal oesophagus are associated with EoE response to PPIs, implying an anti‐reflux mechanism of action as most likely.