Minimal Clinically Important Difference of Reflux Symptom Score, Reflux Symptom Score‐12, and Reflux Symptom Index
Jérôme R. LechienAbstract
Objective
To establish the minimal clinically important difference (MCID) of reflux symptom score (RSS), reflux symptom score‐12 (RSS‐12), and Reflux Symptom Index (RSI).
Design
Prospective study.
Setting
University hospital.
Method
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.
Results
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%).
Conclusion
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.