A Prospective Controlled Study Investigating Odor Identification in Laryngopharyngeal Reflux

To psychophysically evaluate olfaction in patients with laryngopharyngeal reflux (LPR).

Prospective controlled study.

Tertiary medical center.

From January 2021 to January 2022, patients with LPR diagnosed with hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring underwent psychophysical evaluation of the sense of smell. Reflux symptoms and findings were assessed with the Reflux Symptom Score (RSS) and Reflux Sign Assessment (RSA). Nasal symptoms were assessed through the Sino-Nasal Outcome Test 22 (SNOT-22). From pre- to posttreatment, patients underwent identification Sniffin' Sticks test and olfactory cleft examination. Clinical outcomes were compared between LPR patients and healthy individuals.

In total, 107 patients and 76 healthy individuals completed the evaluations. LPR patients reported significant higher RSS, RSA, and SNOT-22 scores. Psychophysical olfactory evaluations were significantly lower in reflux patients compared with controls, while there were no significant differences in olfactory cleft score. RSS and RSA significantly improved from baseline to 3 months posttreatment. SNOT-22, olfactory cleft endoscopy scale, and psychophysical olfactory evaluations did not change throughout treatment. Patients with higher number of acid pharyngeal reflux events reported lower psychophysical olfactory scores (P = .025).

LPR disease was associated with low odor identification results in patients without olfactory cleft abnormalities. The sense of smell did not improve after 3-month therapy. Future controlled studies using threshold, discrimination, and identification testing are needed.