Cost-effectiveness analysis of antiemetic therapy for ambulatory surgery.

STUDY OBJECTIVE

To compare the relative cost-effectiveness ratios of (1) therapy with ondansetron, droperidol, and metoclopramide in the prevention of postoperative nausea and vomiting (PONV), and (2) prophylactic versus rescue therapy of PONV with these agents.

DESIGN

Cost-effectiveness analysis based on the estimated costs of 12 mutually exclusive outcomes identified by decision analysis.

SETTING

Computer model of outcome established using data extracted from published studies and a survey of current practice in two university-affiliated hospitals.

PATIENTS

Patients undergoing operations associated with a high risk of PONV.

INTERVENTIONS

The cost-effectiveness of prophylactic antiemetic therapy was compared among three drugs and also compared with limiting treatment to established PONV.

MEASUREMENTS AND MAIN RESULTS

Direct costs included drug acquisition, drug delivery, equipment used in managing vomiting, and additional nursing time costs. Indirect costs included drugs and materials used to treat persistent nausea and/or vomiting and the side effects of prophylactic drugs, increased time spent in the postanesthesia care unit, unanticipated hospitalization, and lost earnings due to hospitalization. Separate models were created for patients with both nausea and vomiting and with isolated nausea. The total incremental costs associated with the prophylactic use of ondansetron, metoclopramide, and droperidol were $37.74, $28.43, and $18.17 per patient, respectively. The costs per emesis-free patient with the prophylactic use of ondansetron, metoclopramide, and droperidol, were $55.91, $71.08, and $30.15, respectively, and per nausea-free patient $68.93, $82.74, and $33.52, respectively. Prophylactic antiemetic therapy was cost-effective for operations with a high frequency of emesis, whereas treatment of established symptoms was more cost-effective when the frequency was lower. For ondansetron, prophylactic use was cost-effective only when the frequency of emesis exceeded 33%, whereas prophylactic droperidol was cost-effective even if the frequency was 10%.

CONCLUSIONS

When drug costs, efficacy, and adverse events were all considered, prophylactic droperidol was more cost-effective than ondansetron, and both drugs were more cost-effective than metoclopramide. However, the expected frequency of PONV, as well as local drug acquisition costs, can significantly influence whether a particular antiemetic is cost-effective when given prophylactically or only as therapy for established PONV.