Diagnosing Laryngopharyngeal Reflux: A Comparison between 24-hour pH-Impedance Testing and Pharyngeal Probe (Restech)...

The purpose of this study was to compare the diagnostic utility of pH monitoring using 24-hour esophageal pH-Impedance (HEMII-pH) testing versus pharyngeal pH (Restech) testing (Respiratory Technology Corporation, Houston, Texas) for diagnosing laryngopharyngeal reflux (LPR).

Retrospectively, patients were reviewed who had completed a Reflux Symptom Index (RSI) survey and stroboscopy within 60 days before or after undergoing simultaneous esophageal pH-Impedance monitoring and Restech testing. Reflux Finding Score (RFS) was determined by 4 blinded observers. 80.45% of patients were on anti-reflux medications at the time of study and had incomplete response to treatment for reflux. Improvement on reflux treatment was determined by evaluating presenting pre-pH monitoring RFS, post treatment RFS, and improvement of symptoms. Pearson correlation coefficients were calculated to assess relationships among RSI, RFS, and test results from HEMII-pH and Restech tests.

Eighty-seven patients were included in the analysis. The inter-rater reliability of the RFS determination was 74.57%, and the intra-rater reliability was 67.00%. Subjects who had a positive RYAN Score had a significant correlation with RFS (r of 0.222 and p-value of 0.0492). There was no correlation between RFS and number or percent time of reflux events, longest event, total number of events, or percent of time at alkaline pH for either HEMII-PH or Restech test. RSI correlated better with HEMII-pH test than with Restech for percent time spent in both upright (r of 0.226 and p-value of 0.029) and supine position (r of 0.261 and a p-value of 0.032). Restech correlated better with total patient symptom Scores including cough, heartburn, burping, and throat clearing, with a r of 0.242 and a p-value of 0.048. Restech detected more percent time in reflux for total reflux, supine reflux, and upright reflux (p-value less than 0.0001). Restech also detected longer event times than Impedance (p-value of less than 0.0001). When diagnosis of LPR is based on the definition of CRC, the Sataloff Score test had 70.45% sensitivity and 80.95% specificity. The RYAN Score had a sensitivity of 72%, and a specificity of 56.45%, and the Wu Score had a sensitivity of 62.16%, and specificity of 54.05%. When the Sataloff and Wu Score were used together, the sensitivity was 71.45%, specificity 100%, positive predictive value of 100%, and a negative predictive value of 59.46%.

The amount of time of reflux events correlates with symptoms better than the number of events. The HEMII-pH test was able to detect more events of pH<4 than Restech, possibly because there might have been more acid events below than above the upper esophageal sphincter, while Restech detected more total events. Restech recorded longer event times than HEMII-pH test. Since length of time correlates with RFS (probably reflecting laryngeal inflammation), and since laryngeal clearance of acid is more similar to pharyngeal than esophageal clearance, this finding might prove valuable clinically. The Sataloff Score has a sensitivity of 70.45%, and a specificity of 80.95% and appears useful clinically to detect mild to moderate that is missed by the RYAN Score. A combination of Sataloff Score and Wu Score may be clinically valuable to identify LPR with an increased sensitivity of 71.45% and increased specificity of 100%. The Wu Score is not yet available for the general clinical use, but the Sataloff Score is.