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Guidance for trials in Helicobacter pyloriinfection
  1. Médico Adjunto,
  2. Servivio de Aparato Digestivo,
  3. Hospital Miguel Servet,
  4. Zaragoza 50009, Spain

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Editor,—Your prestigious journal has recently published a supplement on guidelines for clinical trials inHelicobacter pylori infection (Gut1997;41(suppl 2):S1–23). I welcome these guidelines, and as it would be expected from the authors’ experience and background, the term excellent would surely be adequate to describe the three different papers contained in the supplement. There are, however, at least two key points that merit discussion before these guidelines are generally applied by the scientific community.

Firstly, a methodological point. Double blind, randomised, controlled, well planned and developed trials do provide very sound and solid scientific evidence for evaluating efficacy. However, other types of trials, even uncontrolled, can give very valuable data on effectivity, and cannot be discarded as long as methods and analysis are correct. In fact, some of the most cited articles are uncontrolled but very elegant studies1 ,2 and some are even case reports.3Sometimes classic methodological rules are avoided but good science is produced.4

Secondly, an ethical point. In the guidelines (pS3) the following sentence is included, “In phase III studies, aiming at regulatory approval of a new drug regimen, one of the reference groups should be given a treatment known to result in no eradication of H pylori...”. This assertion is clearly in conflict with the Declaration of Helsinki, mentioned as an ethical reference by the authors on the same page. As recently pointed by Angell,5the Declaration of Helsinki states, “In any medical study, every patient—including those of a control group, if any—should be assured of the best proven diagnostic and therapeutic method”. If prospective study subjects have peptic ulcer disease, current recomendations are mandatory: H pylori should be eradicated.6 In fact, the same group of authors have very recently stated inGut that, “...H pylori eradication is strongly recommended in all infected patients with a diagnosis of duodenal or gastric ulcer disease, past or present...”, a sentence based on “unequivocal supporting evidence”.7 I think that patients should come first and methodology second,5 8 9 and strongly suggest that this sentence should be removed from the guidelines, or at least limited to pathologies with “equivocal” evidence such as functional dyspepsia.