Use of 24-hour oesophageal pH-metry for the detection of gastro-oesophageal reflux in infants: what is the ideal score and the optimal threshold? A receiver-operating-characteristic analysis.Ital J Gastroenterol Hepatol. 1997 Aug; 29(4):297-302.IJ
The search for the ideal score and best cut-off value to interpret the data from 24-hour continuous pH-monitoring interests both gastroenterologists with adult patients and paediatric gastroenterologists.
To evaluate 24-hour continuous pH monitoring as a discriminatory test in the diagnosis of gastro-oesophageal reflux disease in a paediatric population, using various pH-metry scores and cut-off values.
One hundred and one patients presenting gastro-oesophageal reflux disease (endoscopic diagnosis of oesophagitis or coincidence between apnoea and reflux episodes observed during pH-metry), median age 10 months, were studied, together with a control group of 84 subjects, median age 11 months.
After plotting the receiver operating characteristic curves and calculating the area below them, the evaluation of the total percentage reflux time proved to have a higher capacity for distinguishing between the patients and controls than the Euler score (p < 0.05). The cut-off value of 5.2% for the total percentage reflux time 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 maximum diagnostic accuracy); specificity, however, was low: 39-61%. In addition, the Jolley score was the most useful parameter in detecting patients with apnoeic episodes secondary to gastro-oesophageal reflux disease and allowed a correct diagnosis in 12/13 cases.
a) The simple determination of total percentage reflux time, according to the methodology used, has a higher predictive capacity than the more complex pH-monitoring scores; b) the best cut-off value for total percentage reflux time is 5.2% as it combines a good specificity and sensitivity which are necessary for this test; c) age-dependent cut-off values 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 episodes of gastro-oesophageal reflux-dependent apparent life-threatening events.