Source: Hepatology  |  Posted 10 years ago

Since proton pump inhibitors came into widespread clinical use, the diagnosis of gastrinoma (Zollinger-Ellison syndrome) has been masked and probably delayed.

As a result, patients with gastrinoma - thought to account for 0.1-1.0 percent of peptic ulcers - will not be diagnosed until their disease is more advanced.

Researchers at the National Institutes of Health, Bethesda, Maryland, United States, and in Rome, Italy, investigated whether the use of proton pump inhibitors might mean that their use could complicate, delay or mask the diagnosis of gastrinoma after realising that the properties of these drugs could lead to that happening.

Proton pump inhibitors are potent acid suppressants which, at normal doses, can result in hypergastrinaemia in patients with idiopathic esophageal reflux disease and can control symptoms in most patients with gastrinomas.

The researchers analysed data from their two centres, which had different referral criteria for suspected gastrinomas. The numbers of referrals and new patients with gastrinoma diagnosed before the widespread use of proton pump inhibitors (1986-1992) were compared with the numbers since (1993-1998).

Significant decreases in referral rates and in the annual rates of gastrinoma diagnosis at both centres correlated with increased use of proton pump inhibitors.

At the Italian centre, annual referrals fell by 62 percent in the period after proton pump inhibitors came into use whereas referral rates for other gastrointestinal endocrine tumours rose. The number of new cases of gastrinoma diagnosed fell by 40 percent.

At the US centre, annual referrals fell by 28 percent in the period after proton pump inhibitors came into use. There was also a 43 percent fall in the number of new cases diagnosed annually.

Analysis also disclosed a 2.6-fold increase in the post-proton pump inhibitor period in the percentage of referrals with a false diagnosis of gastrinoma as the cause of hypergastrinaemia.

The researchers concluded that, in both referral centres, fewer patients had been referred with a possible diagnosis of gastrinoma. Also, fewer new patients with gastrinoma had been diagnosed since proton pump inhibitors became widely available.