Study designs of evaluations included in the review
Only double-blind randomised controlled trials (RCTs) with at least 10 participants, which suffered from less than 20% drop-out in any study arm and with no other unanticipated methodological flaws, were eligible for inclusion in the review.
Specific interventions included in the review
Studies that compared an oral PPI with placebo were eligible for inclusion. Studies that assessed the effectiveness of PPIs in combination with other potentially active interventions were excluded. The studies included in the review assessed the effectiveness of 40 mg twice daily doses of omeprazole and pantoprazole. The duration of treatment was 21 days and 30 days.
Participants included in the review
Eligible studies had to include individuals over the age of 18 years who were suffering from at least one of the following laryngopharyngeal reflux symptoms: hoarseness, excessive throat clearing, globus sensation, excessive phlegm, sore throat or chronic cough. Other causes had to be excluded and participants had to have experienced symptoms for at least 2 months. All eligible participants should have received 24-hour ambulatory oesophageal pH monitoring in order to confirm the presence of reflux. Both of the reported studies included patients who had experienced symptoms of chronic laryngitis for at least 3 months. Other causes were excluded by flexible laryngoscopy, and 24-hour dual-channel pH probe measurements were used to confirm the presence of reflux.
Outcomes assessed in the review
Eligible studies had to report a symptom score for laryngopharyngeal reflux, defined as a composite score of throat pain, hoarseness, foreign body sensation in the throat, throat clearing and cough. Other eligible outcomes included an improvement in endoscopic laryngeal signs or pH readings evaluated by 'pH metry'. The included studies used two different patient-assessed scoring systems: a visual analogue score (VAS) with between 0 to 1,400 points reflecting both the severity and frequency of symptoms, and a composite score between 0 and 72 derived from a 4-point symptom scale adjusted for the frequency of symptoms.
How were decisions on the relevance of primary studies made?
Two reviewers performed the literature searches, but the authors did not state how the papers were selected for the review, or how many reviewers performed the selection.