Figure 2 Correlation of LPR and sleep parameters. RSI and RSF scores were positively correlated with AHI (A) and CT90 (B), and negatively correlated with L-SpO2(C). RSI: reflux symptom index, RFS: reflux finding score. AHI: apnea hypopnea index; CT90: percentage of recording time when oxygen saturation of arterial blood<90%; L-SpO2: lowest SpO2 during sleep.