Helicobacter pylori therapy demystified.

We discuss the role of comparators in Helicobacter pylori treatment trials and why anti-H. pylori therapeutic trials (an infectious disease) are fundamentally different from common gastrointestinal diseases (e.g., the absence of a placebo response, the expectation that cure rates in excess of 95%, and the ability to understand why treatment fails). No comparator is absolutely required other than to 100% success and comparison trials should be limited to comparisons between therapies that reliably achieve 90% or greater success (i.e., good therapies). Comparisons with known low success regimens (i.e., bad therapies) are unethical as is withholding information from the subject regarding current effectiveness of a regimen even if that information would reduce the likelihood that the subject would volunteer. We also discuss how it is possible to predict the outcome of a published but locally untried new regimen. The reason for different outcomes of typical gastrointestinal therapies is shrouded in mystery. In contrast, treatment success for H. pylori should be predictable and treatment failures explainable. For too long expectations and analyses of H. pylori therapy has been confused with what is appropriate for gastrointestinal disease such as constipation or irritable bowel syndrome rather than for infectious diseases such as pneumonia.