Incidence of chemotherapy-induced nausea and vomiting in Taiwan: physicians' and nurses' estimation vs. patients' reported outcomes.

BACKGROUND: The major objective of the study was to determine the incidence and prevalence of acute and delayed chemotherapy-induced nausea and vomiting (CINV) among patients receiving chemotherapy and assess the accuracy with which medical providers perceive the incidence of CINV in their practice.
METHODS: Specialists, residents and nurses (medical providers) from two cancer centers in Taiwan estimated the incidence of acute and delayed CINV. Chemotherapy-naive patients from the same centers then completed a 5-day nausea and vomiting diary following highly and moderately emetogenic chemotherapy (HEC and MEC) to determine the actual incidence of acute and delayed CINV. Daily nausea ratings were recorded on a 100-mm visual analogue scale (VAS). No nausea was defined as a nausea VAS score <5 mm. Vomiting episodes were also recorded. Nausea and vomiting were defined as acute and delayed based on whether they occurred during the first 24 h after chemotherapy, or during days 2-5 after chemotherapy, respectively.
RESULTS: In the two oncology centers, 37 medical providers (13 specialists, 4 residents, 20 nurses) and 107 patients were enrolled. The mean patient age was 49.2 years with 76% female and 74% having breast cancer. Of the 107 patients, 39% received HEC and 61% received MEC, and 77% received a 5-HT3 receptor antagonist and 94% received dexamethasone. There were no significant differences between patients with acute CINV and delayed CINV in terms of demographics, chemotherapy treatment or antiemetic treatment. The proportion of patients without alcohol use was significantly higher among patients with delayed CINV than among those with non-delayed CINV. Good control of CINV during the acute period correlated with the control of delayed emesis. There were no significant differences between specialists', residents', and nurses' estimations of the incidence rates of CINV. For HEC given to chemotherapy-naïve patients, the medical providers estimated acute CINV to be 44/41% and delayed CINV to be 61/53%, respectively. However, patient diaries revealed acute CINV to be 43/21% and delayed CINV to be 64/60%, respectively. For MEC given to chemotherapy-naive patients, medical providers estimated acute CINV to be 39/36% and delayed CINV to be 44/39%, respectively. However, patient diaries revealed acute CINV to be 55/18% and delayed CINV to be 74/55%, respectively.
CONCLUSIONS: Medical providers significantly overestimated the incidence of acute vomiting by 20% and 18% in HEC and MEC patients, respectively. While they correctly estimated the rate of delayed vomiting in HEC patients, they underestimated it by 16% in MEC patients. With respect to nausea, medical providers correctly estimated rates of both acute and delayed nausea in HEC patients, but significantly underestimated rates of acute and delayed nausea by 16% and 30%, respectively, in MEC patients.