Validity and reliability of the reflux symptom score

Objectives/hypothesis: To develop and validate the Reflux Symptom Score (RSS), a self-administered patient-reported outcome questionnaire for patients with laryngopharyngeal reflux (LPR).

Study design: Prospective controlled study.

Methods: A total of 113 patients with LPR were enrolled and treated with diet and 3 months of pantoprazole, alginate, and/or magaldrate depending on the LPR characteristics (acid, nonacid, or mixed). Eighty asymptomatic individuals completed the study. Patients and controls completed the RSS twice within a 7-day period to assess test-retest reliability. Internal consistency was measured using Cronbach's α for the RSS items in patients and controls. Validity was assessed by comparing the baseline RSS with the Reflux Symptom Index (RSI) and Voice Handicap Index (VHI). Seventy-seven patients completed the RSS at baseline and after 6 and 12 weeks of treatment to assess responsiveness to change. The RSS cutoff for determining the presence and absence of LPR was examined by receiver operating characteristic analysis.

Results: Test-retest reliability (r_s = 0.921) and internal consistency reliability (α = 0.969) were high. RSS exhibited high external validity indicated by a significant correlation with the RSI (r_s = 0.831). Internal validity was excellent based on the higher RSS in patients compared with controls (P = .001). RSS, RSI, and VHI scores significantly improved from pre- to posttreatment, indicating a high responsiveness to change. RSS >13 can be considered suggestive of LPR-related symptoms. RSS was not influenced by the occurrence of gastroesophageal reflux disease, LPR subtypes, or patient characteristics.

Conclusions: RSS is a self-administered patient-reported outcome questionnaire that demonstrates high reliability and excellent criterion-based validity. RSS can be used in diagnosing and monitoring LPR disease.

Level of evidence: 3b Laryngoscope, 130:E98-E107, 2020.