Editor,—A reading of the recent article by Eggleston et al (Gut1998;42:13–16) left several unanswered questions and concerns. The first issue was the authors’ statement that clinical equivalence between cisapride, ranitidine, and omeprazole had been established for uncomplicated gastro-oesophageal reflux disease (GORD) in standard practice. To my knowledge, there are no published studies which have reported a similar finding of clinical equivalence of omeprazole to either cisapride or ranitidine. A quick review of the literature revealed 11 studies in which omeprazole was statistically significantly better than cisapride or ranitidine in GORD.1-11

In a review of the reference abstract12 in which the case for clinical equivalence is postulated, the conclusion of equivalence was highly dependent upon the authors’ definition of treatment failure. I take exception to the authors’ definition that use of medication for longer than three months was a therapy failure. A retrospective database analysis does not have the ability to distinguish between continuing a medication in order to maintain successfully achieved symptom resolution and continued use of medication due to unsuccessful resolution of symptoms. Initiation of maintenance therapy after successful symptom resolution would not require any change in dosage in the case of omeprazole as 20 mg once daily is the recommended dose for healing and maintenance. Defining success as any use of medication for less than three months that did not involve a change in drug also opens up the possibility of misclassification. Those patients who stop using a drug as a result of treatment failure and who do not return for further care would not only be misclassified in this retrospective analysis as a success but could erroneously contribute to a lower economic burden in the therapy group. In the Methods, the authors state that case records for a total of …