Nocturnal gastric secretion in duodenal ulcer patients and healthy controls. Ranges and reproducibility.

The nocturnal gastric acid secretion of 22 male duodenal ulcer patients was compared with that of 47 healthy male volunteers. Median nocturnal acid output was greater in duodenal ulcer patients (55 mmol versus 33 mmol 10 h-1; p = 0.013), but there was almost complete overlap of the ranges. Five duodenal ulcer patients and three volunteers had nocturnal outputs of acid previously considered to be pathognomonic of the Zollinger-Ellison syndrome in the absence of other evidence of a gastrinoma. Nineteen healthy volunteers underwent a repeat study to assess the reproducibility of nocturnal gastric acid output. Median intraindividual variability (+/- distribution-free 95% confidence limits) was 23% (-34% to +72%). Studies of nocturnal gastric secretion are of no diagnostic value, and their variability should be taken into consideration when evaluating gastric antisecretory drugs.