Lower Oropharyngeal Acid Exposure and Higher Psychological Distress Exists Amongst Subjects With Laryngeal Symptoms and Response to PPI Therapy

Abstract

Introduction: Predicting therapeutic response in patients with laryngopharyngeal reflux (LPR) symptoms is challenging. Consequently, patients with suspected LPR often receive empiric proton-pump inhibitor (PPI) therapy and up to 50% may not respond. The Restech Dx-pH probe is a transnasal catheter that measures oropharyngeal pH. We hypothesized that higher oropharyngeal acid burden is associated with a greater PPI response. The aims of this study were to (1) correlate oropharyngeal pH probe parameters with PPI response and (2) evaluate if alternative clinical surrogates predict PPI response. Methods: This was a physician blinded prospective cohort study conducted at a tertiary care teaching institution between 1/2013 and 10/2014. Adult subjects with laryngeal symptoms >1 month and a Reflux Symptom Index score (RSI) ≥13 off PPI therapy 2 weeks prior to study were recruited from an otolaryngology clinic. Laryngoscopy and oropharyngeal pH assessment with the Restech Dx-pH system were first performed, followed by an 8 to 12 week trial of omeprazole 40 mg once daily. Prior to, and following PPI therapy, subjects completed various symptom questionnaires [Table 1]. PPI response was defined as > mean delta RSI (difference between pre- and post-PPI therapy RSI).Table 1: Clinical variables by PPI Responder & Non-responder groupsResults: Of 34 subjects, 15 (44%) had a PPI response. Percent time of oropharyngeal pH below 5.0 did not correlate with change in RSI (Spearman's rho -0.07, P=0.7); similar trends were seen for pH < 4.0, 5.5 & 6.0. Low acid exposure ( < 1%) was significantly associated with PPI response when compared to high acid exposure (≥1%) [Figure 2]. PPI responders had higher psychological distress scores prior to treatment and a significantly greater reduction in post-treatment Brief Symptom Index, Negative Affect, and Heartburn Vigilance Scale scores. Baseline and delta GerdQ scores were significantly higher in the PPI responder group.Figure 2Conclusion: Contrary to our hypothesis, low oropharyngeal acid burden was associated with PPI symptom response, suggesting a non-acid mechanism of laryngeal symptoms in this group. PPI responders had higher psychological distress, indicating an association between cognitive affective symptoms and laryngeal complaints and supporting the placebo effect of PPI therapy. The etiology of laryngeal symptoms is undoubtedly complex, and the role of oropharyngeal pH testing to predict PPI response remains unclear.Figure 1