Methodology and assessment in clinical anti-emetic research: a meta-analysis of outcome parameters

There have been major clinical advances in the control of chemotherapy-induced nausea and emesis. These advances were achieved partly by the introduction of new anti-emetic agents but important improvement came from the use of existing agents in ways developed from the results of studies based on new approaches and methods in anti-emetic research. By developing basic research tools, improving methodology and applying psychometrically sound assessments better management or chemotherapy-induced nausea and vomiting has been achieved. The goals of anti-emetic assessment are discussed here along with data and examples of assessment techniques for emesis and nausea. Examination of 153 separate anti-emetic studies between the years of 1975 and 1988 showed that emesis was the most common outcome measure used and that approximately 1 out of five studies measured some other type of outcome usually in the context of nausea and emesis. The frequency of outcome events was most commonly the dimension assessed. Examination of size of the effect of an anti-emetic regimen for these anti-emetic studies showed it to be independent of the type of outcome measured, but to be quite dependent on how the outcome was quantified. For instance, differences in the frequency or incidence of either nausea or emesis were generally larger than measurements made of the duration of either of these.