Background: Multichannel intraluminal impedance (MII) is a pH-independent method of assessing gastroesophageal reflux.
Aim: To evaluate the diagnostic accuracy of MII-pH as compared with conventional pH monitoring in detecting reflux events (REs) and symptom association in different age groups.
Methods: : A prospective direct comparison of 2 diagnostic techniques on 291 consecutive patients referred for suspected gastroesophageal reflux disease. Sensitivity and diagnostic accuracy of MII-pH versus pH monitoring and symptom association were measured.
Results: MII-pH detected 13631 REs, 6260 (46%) of which were nonacid. The prevalence of weakly acid refluxes in the 24 hours and postprandial period as well as the proximal extension of refluxate were significantly greater in infants as compared with children (P < 0.001, P < 0.001, and P < 0.01, respectively). The diagnostic accuracy of combined MII-pH in revealing all RE and acid RE were significantly higher in infants as compared with children (92% vs 82%, P < 0.01 and 83% vs 76%, P < 0.04, respectively). The addition of MII to conventional pH monitoring significantly increases the diagnostic yield of symptom association analysis in revealing an association between atypical symptoms and refluxes irrespective of age, whereas in studying typical symptoms it was true only for infants.
Conclusions: Addition of MII to conventional pH monitoring significantly increases the diagnostic yield in detecting REs, prevalently in infants, and in revealing an association between refluxes and symptoms, prevalently respiratory ones and in infants group.