THE OPTIMAL DURATION OF pH-MONITORING: TESTING THE VALIDITY OF LYON 2.0 RECOMMENDATIONS FOR WIRELESS pH MEASUREMENT

Background and aims: The Lyon 2.0 consensus recommends 96-hr wireless pH studies for GERD diagnosis; however, the optimal length of pH-measurement has not been established. Further it is uncertain if, and under what circumstances, shorter recording times are sufficient for a conclusive diagnosis.

Methods: Data from 944 patients with 4-day recordings was reviewed. Patients were classified at 24, 48, and 72-hrs against the 96-hr reference standard. Acid exposure time (AET) <4% was conclusively negative and AET >6% conclusively positive for GERD. Esophagitis was an independent marker of disease. The effect of utilizing average day, worst-day, and dominant-pattern analysis (≥2 negative or positive days) was compared. Groups defined by AET thresholds from 1% to 7% at 24- and 48-hr were followed to assess when short recording periods were sufficient for conclusive diagnosis.

Results: Diagnostic accuracy improved with study duration (p < 0.00001). The proportion of patients with inconclusive results (AET 4-6%) reduced from 113/944 at 24-hr to 40/113 at 96-hr (35% of subgroup; p = 0.02), with similar results for dominant pattern analysis. Diagnostic sensitivity for 24, 48 and 72-hr pH-monitoring for AET 6% threshold increased with study duration from 62.5% to 76.6% and 88.2%, respectively, when compared to the 96-hour reference standard.

Conclusion: The results of this analysis validate the recommendation that prolonged reflux studies of at least 72-hr duration provide optimal AET measurements for GERD diagnosis. Prolonging studies can also resolve inconclusive results based on 24- and 48-hr studies.