USE OF 24-HOUR ESOPHAGEAL PH-METRY FOR THE DETECTION OF GASTROESOPHAGEAL REFLUX IN INFANTS - WHAT IS THE IDEAL SCORE AND THE OPTIMAL THRESHOLD - A RECEIVER-OPERATING-CHARACTERISTIC ANALYSIS

The search for the ideal score and best cut-off value to interpret the data from 24-hour continuous pH-monitoring interests both gastroenter ologists with adult patients and paediatric gastroenterologists. Aims. To evaluate 24-hour continuous pH monitoring as a descriminatory test in the diagnosis of gastro-oesophageal reflux disease in a paediatric population, using various pH-metry scores and cut-off values. Patient s. One hundred and one patients presenting gastrooesophageal reflux di sease (endoscopic diagnosis of oesophagitis or coincidence between apn oea and reflux episodes observed during pH-metry), median age 10 month s, were studied, together with a control group of 84 subjects, median age 11 months. Results. After plotting the receiver operating characte ristic curves and calculating the area below them, the evaluation of t he total percentage reflux time proved to have a higher capacity for d istinguishing between the patients and controls than the Euler score ( p<0.05). The cut-off value of 5.2% for the total percentage reflux tim e had a sensitivity of 75% and was 88% specific. Using higher cut-off values according to age, a 95% specificity and a 49% sensitivity were obtained The most sensitive score was the Jolley score: 96% with a cut -off of 64 and 90% with a cut-off of 100 (a value determining the maxi mum diagnostic accuracy); specificity, however was low: 39-61%. In add ition, the Jolley score was the most useful parameter in detecting pat ients with apnoeic episodes secondary to gastro-oesophageal reflux dis ease and allowed a correct diagnosis in 12/13 cases. Conclusions. a) T he simple determination of total percentage reflux time, according to the methodology used, has a higher predictive capacity than the more c omplex pH-monitoring scores; b) the best cut-off value for total perce ntage reflux time is 5.2% as it combines a good specificity and sensit ivity which are necessary for this test; c) age-dependent cut-off valu es are highly specific but sensitivity is much too low; d) the Jolley score is very sensitive and this was maintained even when the cut-off was raised to a value of 100; it is the best predictive score for epis odes of gastro-oesophageal reflux-dependent apparent life-threatening events.