Objectives: To identify variables contributing to discrepant gastroesophagopharyngeal acid reflux (GEPR) findings and to critically assess the prevalence of GEPR in healthy individuals and patients with reflux laryngitis (RL).
Study design: Quantitative systematic review.
Methods: Pharyngeal pH monitoring studies of healthy individuals and patients with RL were identified through a MEDLINE search of publications between 1966 and 2003. Pooled results of the measured pharyngeal acid exposure characteristics and the prevalence of GEPR events were analyzed. Statistical comparisons were performed using a chi 2 test.
Results: The study included 181 controls and 184 RL patients. Subjects' age ranged from 19 to 85 years. Gastroesophagopharyngeal acid reflux events were detected at 1, 2, and 4 cm above upper esophageal sphincter (UES) and 0.5 cm below arytenoids, with varying rates. The prevalence of GEPR ranged from 0% to 83% in controls and 27% to 86% in RL. After excluding the healthy subjects with abnormal esophageal acid exposure, prevalence of GEPR decreased from 35% to 17% (P<or=.002). Gastroesophagopharyngeal acid reflux in RL was significantly more prevalent than in the entire group of controls as well as in controls without abnormal esophageal acid exposure (P<or=.001).
Conclusions: The prevalence of GEPR in controls and patients with RL varies in the studied 4 areas above the UES. The percentage of the subjects with GEPR increased as the probe was located more closely to the UES. Differences in demographic characteristics of the subjects, interventions used to select subjects, and pharyngeal pH monitoring techniques were identified as factors possibly contributing to inconsistent pharyngeal pH monitoring findings. The documented differences in methodology of existing studies make comparison of the studies difficult.