Role of *Helicobacter pylori* infection

Although GI injury (peptic ulcers or erosive gastropathy) is the most frequently observed side effects in patients on chronic NSAIDs therapy, presence of *Hp* infection is the most common cause of peptic disease in patients not on NSAIDs therapy. It was estimated that chronic *Hp* infection was present in about 50% of the population worldwide; however, only a little amount of these patients (5-10%) will develop GI injuries. Risk factors for development of Hp-related peptic ulcers are not well understood; however, different histological pattern of gastritis, change in acid secretion, the presence of duodenal gastric metaplasia, ulcerogenic bacterial strains and host genetic factors are all involved. For example, the relative risk to present peptic ulceration is increased in patients infected by the CagA-positive bacterial strain (Pilotto, 1997; Covacci, 1993; Li, 1999; van Doorn, 1998; Garcia Rodriguez, 1994; Huang, 2002).
