Functional dyspepsia is associated with cagA-positive Helicobacter pylori strains

The antigen CagA can be used as a marker for virulence of Helicobacter pylori. It is tempting to assume that H. pylori strains positive for cytotoxin-associated gene A (cagA) could be responsible for functional dyspepsia. A cross-sectional study was performed in patients presenting with functional dyspepsia to correlate the clinical presentation with the presence of cagA-positive and -negative H. pylori strains.

Consecutive patients referred for endoscopy were studied. An inclusion criterion was the absence of any endoscopic abnormality. Biopsy specimens were obtained from the gastric antrum for HE and immunoperoxidase stain, rapid urease test, and culture. A serum sample was taken for detection of IgG antibodies against H. pylori as well as CagA. A validated questionnaire of 14 questions regarding the upper gastrointestinal tract was used for assessment of the clinical presentation. Nine questions were scored on a 5-point Likert scale.

422 patients were included, 222 were H. pylori-positive, the remaining 200 were H. pylori-negative. Mean symptom score in patients with cagA-positive strains was significantly higher than in patients with cagA-negative strains. No difference was present if cagA-negative patients were compared with H. pylori-negative dyspeptics. Four different complaints were more prevalent in the cagA-positive patients compared with cagA-negatives. When cagA-positive patients were compared with H. pylori-negative dyspeptics, seven complaints were significantly more prevalent in cagA-positives; when cagA-negatives were compared this number was only two.

Functional dyspeptics with cagA-positive H. pylori strains have more dyspeptic symptoms and higher symptom scores than patients with cagA-negative H. pylori strains as well as H. pylori-negative functional dyspeptics.