The Utility of the Reflux Symptom Index for Diagnosis of Laryngopharyngeal Reflux in an Allergy Patient Population

Abstract

Laryngopharyngeal reflux (LPR) is associated with asthma, vocal cord dysfunction, cough, postnasal drainage, and throat irritation. The Reflux Symptom Index (RSI) is a clinical tool to predict the presence of LPR, but a threshold RSI score has never been validated for the diagnosis of LPR in an allergic patient population. To identify the optimal threshold RSI score predictive of LPR in an allergy clinic population. The 9-question RSI questionnaire was administered to 84 patients in the Kaiser Permanente San Diego Allergy Department. The patient's allergist (who was blinded to the patient's RSI responses) was asked to determine whether the patient had symptoms consistent with LPR. Each subject's RSI score was then compared with a corresponding physician-based diagnosis. After determining the correlation between the subject's RSI score and physician-diagnosed LPR/supraesophageal reflux, a cutoff level above which LPR/supraesophageal reflux would be highly suspected was calculated on the basis of most optimal balance of sensitivity and specificity determined via a receiver-operating curve analysis. Thirty of the 84 patients (36%) were diagnosed withLPR. The mean RSI score for the group without LPR was 18.3 ± 9.8 (out of 45 possible), while the LPR group's mean was 25.0 ± 8.3 (P < .01). The optimal RSI score cutoff was determined to be 19. An abbreviated questionnaire was also generated using 6 of the RSI questions found to be significantly different between patients with and without LPR. An RSI score of 19 appears to represent the best threshold for predicting LPR in an allergy clinic patient population.