Chemotherapy induced nausea and emesis in pediatric cancer patients: external validity of child and parent emesis ratings.

Children's and parent's subjective ratings of the frequency and severity of nausea and emesis were assessed among 33 children with acute lymphoblastic leukemia receiving identical chemotherapy. Parents were trained to record the frequency of the child's actual emesis episodes during chemotherapy. Although parent and child ratings of nausea were significantly correlated, children generally rated their nausea and emesis as more frequent and more severe than did their parents. Parent ratings showed inadequate external validity when compared with behavioral observations. Children with greater anxiety and higher subjective ratings subsequently exhibited more frequent episodes of emesis by observation, suggesting that their perceptions of symptoms based on previous chemotherapy experiences may predict emesis during different chemotherapy. In a stepwise multiple regression analysis, antiemetic regimen and the child's anxiety as rated by the parent combined to account for approximately 47% of the variance in number of episodes of emesis. These findings are discussed in the context of factors limiting validity of parent and child reports of children's symptomatology with implications for future epidemiologic and intervention research.