The Revised Reflux Symptom Index (R-RSI): development, internal and external validation study.

ABSTRACT

INTRODUCTION: This study proposes a revised version of the Reflux Symptom Index (R-RSI), a seventeen-item questionnaire that was revised to increase the suspicion of laryngo-pharyngeal reflux disease (LPRD). METHODS: Internal validation involved 213 participants, comprising160 subjects without a previous LPRD diagnosis and 53 subjects with a self-reported previous diagnosis of LPRD with or without gastro-esophageal reflux disease (GERD). Test-retest reliability and internal consistency were calculated. For the external validation, 56 patients (independent from the previous cohort) were enrolled to explore the R-RSI Screening Properties and determine a cut-off using 24-h MII-pH as the gold standard. RESULTS: R-RSI test-retest reliability was high, both for the total score (ICC 0.970) and for each item (ranging from 0.876 to 0.980). Cronbach's alpha was 0.910, indicating excellent internal consistency of the questionnaire. Participants with a previous self-reported diagnosis scored significantly higher (mean 24.94 ± 7.4; median 26, IQR 20-29) than those without a previous diagnosis (mean 4.66 ± 5.3; median 4, IQR 1-6) (p-value < 0.0001). Participants with both previous LPRD and GERD diagnoses had higher scores (27.20 ± 7.8) compared to those with only LPRD (21.77 ± 5.5) (p-value=0.003). Using 24-h MII-pH diagnosis as a gold standard, the optimal R-RSI cut-off point was determined to be 18, with a sensitivity of 84.5% and a specificity of 81.8%, positive predictive value of 95% and negative predictive value of 60%. CONCLUSIONS: Our results suggest that the R-RSI may be useful to suspect LPRD, with or without GERD. The R-RSI is a self-administered patient-reported outcome questionnaire that demonstrates excellent reliability and high screening properties. Employing a cut-off of ≥18 the R-RSI can assist in diagnosing and monitoring LPRD.