Minimal Clinically Important Difference of Reflux Symptom Score, Reflux Symptom Score-12, and Reflux Symptom Index.

Abstract

To establish the minimal clinically important difference (MCID) of reflux symptom score (RSS), reflux symptom score-12 (RSS-12), and Reflux Symptom Index (RSI). Prospective study. University hospital. Patients with laryngopharyngeal reflux disease (LPRD) at 24-hour hypopharyngeal-esophageal impedance pH monitoring were prospectively recruited from the European Reflux Clinic. Pretreatment to posttreatment symptoms and findings were assessed with RSS, RSS-12, RSI, and reflux sign assessment (RSA). Baseline LPRD severity (mild, moderate, severe) was determined using the RSS-Quality-of-Life (RSS-QoL). Therapeutic response was defined as improvement by at least one severity category regarding the IFOS classification based on post-treatment RSS-QoL. MCID was evaluated using receiver operating characteristic (ROC) curve analysis and Youden-index. Evaluation was completed by 351 consecutive patients (208 females), including 127 responders to treatment (36.2%) and 224 (63.8%) partial or nonresponders. RSS-QoL demonstrated strong correlations with RSS (ρ = 0.697), RSS-12 (ρ = 0.783), and RSI (ρ = 0.776; all P < .001), validating its use as anchor. Responders showed significantly greater score improvements than non-responders for all patient-reported outcome measures (P < .001). ROC analysis revealed excellent discriminative ability for RSS (AUC = 0.822; 95% CI: 0.78-0.87), RSS-12 (AUC = 0.827; 0.78-0.87), and RSI (AUC = 0.867; 0.76-0.97). MCID values were 35 points for RSS, (sensitivity 81.1%, specificity 69.6%), 20 points for RSS-12 (sensitivity 85.3%, specificity 68.2%), and 8 points for RSI (sensitivity 77.3%, specificity 88.6%). The MCID for improvement in RSS, RSS-12, and RSI in LPRD patients is a decrease of 35, 20, and 8 points, respectively. This information improves the understanding of therapeutic response, allowing for drug class discontinuation and weaning.