Adverse events of HP eradication: long-term negative consequences of HP eradication

Two problems can be identified as possible long term negative consequences of HP eradication: diminished efficacy of acid-lowering drugs, and an accelerated development of GERD. It was shown that omeprazole produces a greater decrease in gastric acidity in subjects with H. pylori infection than in those who are H. pylori negative, and that omeprazole produces a smaller decrease in gastric acidity after cure of H. pylori. This effect persisted for at least one year after HP eradication. It is not limited to omeprazole, but can also be seen with the H2 receptor antagonist ranitidine. At least one proven mechanism involved in this phenomenon is the disappearance of the alkalinizing effect of ammonia, generated from urea by HP's urease, after eradication of the bacteria; other mechanisms may also be involved. HP eradication may therefore potentially hamper acid inhibitory treatment. It is unknown to what extent this is clinically relevant. Although one study did not observe a relation between H. pylori status and efficacy of omeprazole maintenance therapy for GERD, it cannot be excluded that some patients may need more potent or higher doses of acid-lowering medication after HP eradication. Three studies suggest that duodenal ulcer patients who were successfully treated with H. pylori eradication therapy, may be at increased risk to develop GERD. Labenz's study finds that the incidence of GERD may be double 3 years after eradication. The life-table analysis suggested that cure of the infection was associated with an increased risk of reflux oesophagitis during the first year after treatment, whereas later the incidence of reflux oesophagitis was similar in both groups. Patients who developed reflux oesophagitis after the cure had a more severe body gastritis before cure, gained weight more frequently after cure, and were predominantly men. There are no data on the fate of the oesophagus after HP eradication in patients with reflux oesophagitis. The data thus strongly suggest that there is a risk for developing reflux oesophagitis after HP eradication in patients with duodenal ulcer. It is unknown whether HP eradication in patients without duodenal ulcer also increases the risk for developing reflux oesophagitis.