Patients and methods
This was a cross sectional comparative study carried out at the General Infirmary at Leeds and the National Cancer Centre Hospital, Tokyo. Three endoscopists (T Gotoda in Tokyo and L Gatta and G Naylor in Leeds) spent two months training together ensuring concordance of patient selection, recruitment and biopsy sites, processing of histological and microbiological specimens, blood sampling, and storage.
Ethics approval for the study was obtained from the local ethics committees. In Leeds, patients were recruited from a “one stop” dyspepsia clinic. Patients gave written consent on the day if they agreed to enter the trial. In Tokyo, patients attending the National Cancer Centre Hospital endoscopy department specifically for investigation of dyspepsia were similarly approached.
In order to calculate sample size, we identified existing data on gastritis for the UK and Japan.
Results from a previous Japanese biopsy study8 had shown normal findings (that is, no evidence of gastritis) in 9.5% of an asymptomatic population aged 20–60+ years. Unpublished data from a Leeds population showed 50.5% of patients in a routine endoscopy series to have normal stomachs. No asymptomatic Western population data existed but as previous studies
9,
10have demonstrated a lack of correlation between symptoms and histological findings in patients with gastritis, we concluded that this comparison was valid for the purpose of our power calculation.
This gave a prevalence of 90.5% and 49.5% for gastritis (of any type) for Japan and Leeds, respectively. Therefore, to detect a difference of 41% in prevalence between the Japanese and English patients with a power of 0.80 and a significance level of 0.05 (alpha two sided), at least 126 patients had to be enrolled from each centre. Twenty one patients from each decennial from 20 to 80 years were therefore recruited from Leeds and Tokyo between May 2000 and April 2002. Inclusion criteria were as follows: age 20–80 years, predominant symptom of epigastric pain and no endoscopic evidence of reflux oesophagitis, peptic ulcer disease, or malignancy (“non ulcer dyspepsia”). Patients were excluded if they had received
H pylori eradication therapy in the past or any non‐steroidal anti‐inflammatory drugs, proton pump inhibitors, antibiotics, or bismuth containing compounds in the previous two weeks or H2receptor antagonists in the previous two days. At endoscopy, five gastric mucosal biopsies were taken as detailed below. Further antral and body biopsies were taken for
H pylori culture. Blood was also taken for
H pylori serology.