To the Editor: The study of treatment of Crohn disease by Dr Feagan and colleagues1 is important because smaller clinical trials are more susceptible to bias, are often less methodologically rigorous, and produce relatively less precise estimates of the true effect of treatment than large multicenter studies. However, the methodology of this study overlooked 2 potential sources of type II error.
First, no measurements were made of essential fatty acid status at the start or end of the trial. It is not possible to assess the quality of the randomization for either the baseline omega-3 status, the baseline intake of the proinflammatory omega-6 fatty acids, or the baseline ratios of omega-6 to omega-3. Additionally, the quality of the intervention cannot be assessed, including omega-3 fatty acid absorption in these patients or their actual adherence to the protocol.