question: Compared to time pH < 4 what was the result of  integrated acidity on the prevalence of both pathologic 24-hour and nocturnal esophageal reflux in the 3rd study?
context: Figure 1-left illustrates that the prevalence of pathologic 24-hour esophageal reflux in the index study was significantly higher (P = 0.0005, McNemar's Test) when measured as time pH < 4 than when measured as integrated acidity.