The roles of patient and observer assessments in anti-emetic trials

The endpoints assessed by both patients and nurses were compared in three anti-emetic studies. In a parallel subjects study, there was no significant difference between the patients' and nurses' assessment of the number of vomiting episodes, but the duration of vomiting, the severity and duration of nausea, and the side-effects of the anti-emetic were given higher scores by the nurses. In two cross-over studies, the patients recorded more vomiting episodes than the nurses, while the nurses recorded more anxiety and sedation than the patients. This resulted in the patients detecting a difference between the side-effects of the anti-emetics being compared that was not apparent from the nurses' forms. Many of the differences reflect differences in the timing and frequency of data collection. Nurses collected data regularly during the assessment period whereas patients reported their experiences only at the completion of 24 h. Both assessments provide useful perspectives on the study outcomes.