Reliability of self-reported questionnaire for epidemiological investigation of Helicobacter pylori eradication in a population-based cohort study.

General population-based cohort studies provide solid evidence on mass Helicobacter pylori (HP) eradication effects. Self-reported questionnaires are occasionally used in such studies to ascertain the HP eradication history. However, reports on the reliability of these questionnaires are lacking. This general population-based cohort study included 899 individuals with HP infection at the baseline survey who were reported to have eradicated it at the 5-year follow-up survey. Of these, the medical records of 280 patients were available for investigation, and the HP eradication status of 93 individuals was ascertained. Their medical records were reviewed, and the reliability of the self-reported questionnaire responses was assessed. Of the 91 individuals who successfully eradicated HP based on the medical records, 90 (98.9%) answered the self-reported questionnaire correctly, with an unweighted kappa value of 0.661 (p < 0.001). The difference between the self-reported and medical records age at eradication was within a 1-year range in most participants (86.8%). Similarly, the HP eradication procedure and the outcomes were reasonably matched. In conclusion, the responses to the self-reported HP eradication questionnaire were almost consistent with the medical records. Thus, HP eradication history assessment by a self-reported questionnaire is reliable for an epidemiological study in the general population.

Preliminary study of automatic gastric cancer risk classification from photofluorography.

AIM: To perform automatic gastric cancer risk classification using photofluorography for realizing effective mass screening as a preliminary study. METHODS: We used data for 2100 subjects including X-ray images, pepsinogen I and II levels, PGI/PGII ratio, Helicobacter pylori (H. pylori) antibody, H. pylori eradication history and interview sheets. We performed two-stage classification with our system. In the first stage, H. pylori infection status classification was performed, and H. pylori-infected subjects were automatically detected. In the second stage, we performed atrophic level classification to validate the effectiveness of our system. RESULTS: Sensitivity, specificity and Youden index (YI) of H. pylori infection status classification were 0.884, 0.895 and 0.779, respectively, in the first stage. In the second stage, sensitivity, specificity and YI of atrophic level classification for H. pylori-infected subjects were 0.777, 0.824 and 0.601, respectively. CONCLUSION: Although further improvements of the system are needed, experimental results indicated the effectiveness of machine learning techniques for estimation of gastric cancer risk.

[Characteristics of group A patients according to the ABC classification for gastric cancer risk screening].

In the ABC classification for gastric cancer risk screening, group A (Helicobacter pylori infection-negative, pepsinogen [PG]-negative) patients are assumed to be at low risk, but some patients do have atrophic gastritis and H. pylori infection. This study aimed to identify the characteristics of group A patients. Healthy adults in Yamagata City who underwent barium radiography and ABC classification participated in the survey. Patient radiographs were randomly interspersed and reviewed by two gastroenterologists who were blinded to the H. pylori and PG statuses. Group A patients (n=1462) was subclassified as follows: atrophic gastritis group, 21.5%; intermediate group, 15.7%; and no atrophic gastritis group, 62.8%. Elderly subjects and those with H. pylori antibody titers of 3.0-9.9U/ml should be carefully evaluated while interpreting the results of the ABC classification for gastric cancer risk screening.