Systematic review and meta-analysis: the relationship between the Helicobacter pylori dupA gene and clinical outcomes

Abstract

BackgroundIn 2005, the first disease-specific Helicobacter pylori virulence factor that induced duodenal ulcer and had a suppressive action on gastric cancer has been identified, and was named duodenal ulcer promoting gene (dupA). However, the importance of the dupA gene on clinical outcomes is conflicting in subsequent studies. The aim of this study was to estimate the magnitude of the risk for clinical outcomes associated with dupA gene.MethodsA meta-analysis of case-control studies which provided raw data on the infection rates with the dupA-positive H. pylori detected by polymerase chain reaction was performed.ResultsSeventeen studies with a total of 2,466 patients were identified in the search. Infection with the dupA-positive H. pylori increased the risk for duodenal ulcer by 1.41-fold (95% confidence interval [CI], 1.12-1.76) overall. Subgroup analysis showed that the summary odds ratio (OR) was 1.57 (95% CI, 1.19-2.06) in Asian countries and 1.09 (95% CI, 0.73-1.62) in Western countries. There was no association between the presence of the dupA gene and gastric cancer and gastric ulcer. Publication bias did not exist.ConclusionOur meta-analysis confirmed the importance of the presence of the dupA gene for duodenal ulcer, especially in Asian countries.

Prevalence of <i>Helicobacter pylori vacA</i>, <i>cagA</i>, <i>dupA</i> and <i>oipA</i> Genotypes in Patients with Gastric Disease

“…In our report, the cagA gene also exhibited a significant association with another virulence factor, the dupA gene, which is a protecting factor against gastric cancer and which is associated with an increased risk for duodenal ulcer [26] Gomes, et al [27] also found a correlation between cagA-positive and dupA-positive strains, but the association was in patients with duodenal ulcers. In a meta-analysis, Shiota, et al [26] reported a higher prevalence of dupA in Western countries than in Eastern countries.…”

“…In a meta-analysis, Shiota, et al [26] reported a higher prevalence of dupA in Western countries than in Eastern countries. The study performed by Gomes, et al [27] revealed an increased prevalence of dupA in Brazilian patients with chronic gastritis (92.3%) and gastric cancer (87.6%), a finding which differed from that provided by Lu et al (2005) in a study on strains from Colombia.…”

The Intact dupA Cluster Is a More Reliable Helicobacter pylori Virulence Marker than dupA Alone

“…Recent reviews state a worldwide prevalence of dupA of ca. 50% and confirm that dupA is a risk factor for DU (13,27). However, several studies have failed to show a significant association between dupA status and gastroduodenal diseases (6,14,24).…”

“…The association between dupA status and disease development is primarily observed in Asian country such as China, Korea, Iraq, and North India. Our meta-analysis showed that infection with dupA-positive H. pylori increased the DU risk (OR ϭ 1.41, 95% CI ϭ 1.12 to 1.76), particularly in Asian countries (OR ϭ 1.57, 95% CI ϭ 1.19 to 2.06), but not in Western countries (OR ϭ 1.09, CI ϭ 0.73 to 1.62) (27). In the present study, although the data regarding gastritis in the U.S. population are limited (3), we showed that the prevalence of dupA in the U.S. population was 69.4%, which is relatively higher than that reported in other countries (13,27).…”

Overview of Methodological Quality of Systematic Reviews about Gastric Cancer Risk and Protective Factors

“…For different H. pylori strains, cagA-positive strains were associated with increased GC risk (Huang et al, 2003;Xu et al, 2006), but not dupA positive strains (Hussein et al, 2010;Shiota et al, 2010). A meta-analysis (Fuccio et al, 2009) based on two RCTs showed that the pooled result of H. pylori eradication in the prevention of GC was 0.46 (95%CI 0.26 to 0.82), suggesting that H. pylori eradication reduced GC risk.…”