Abstract
Two hundred twenty patients were studied to investigate the chronobiological patterns of gastroesophageal reflux (GER) during a 24-h period of pH monitoring under standardized conditions. Some 204 patients met the inclusion criteria; 120 had normal values and 84 were pathologic. The hourly parameters calculated in the two groups were: the mean pH, the percentage of time during which the pH was smaller than 4, the number of reflux episodes, and the coefficient of variation of the pH. Two types of 24-h rhythms were found. There was an increase of the number of refluxes during the daytime versus the nighttime and the hourly mean pH was more acid during the night than day in subjects with normal values. All parameters differed significantly between the two groups (p < 0.001) and displayed a rhythmic pattern (p < 0.0001). The most significant difference occurred during the 3 postprandial hours after the evening meal (p < 0.001). Temporal rhythmicity of GER could also contribute to evaluation of clinical results in response to antisecretory drugs.