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Cost-effectiveness of prophylactic dolasetron or droperidol vs rescue therapy in the prevention of PONV in ambulatory gynecologic surgery |
Frighetto L, Loewen P S, Dolman J, Marra C A |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology Prophylactic therapy versus rescue therapy in the prevention of post-operative nausea and vomiting (PONV) in ambulatory gynaecologic surgery.
Economic study type Cost-effectiveness analysis.
Study population Ambulatory gynaecology surgery patients.
Setting Hospital. The study was carried out at the Vancouver Hospital and Health Sciences Centre, Vancouver, British Columbia, Canada.
Dates to which data relate Effectiveness data were collected from studies published between 1988 and 1998. Resource use and cost data were collected from studies published between 1992 and 1995. The price year was 1998.
Source of effectiveness data Effectiveness data were derived from a literature review.
Modelling A decision analytic model was used to assess costs and outcomes associated with the various strategies.
Outcomes assessed in the review The review assessed the following outcomes: probability of PONV, probability of rescue therapy, probability of readmission due to PONV, probability of adverse effects, and probability of treatment of adverse effects.
Study designs and other criteria for inclusion in the review Sources searched to identify primary studies Criteria used to ensure the validity of primary studies Methods used to judge relevance and validity, and for extracting data Effectiveness estimates were based on summary statistics from individual studies.
Number of primary studies included Approximately 18 studies were included in the review.
Methods of combining primary studies Investigation of differences between primary studies Results of the review The probability of PONV was 42% with droperidol or dolasetron and 62% with rescue therapy. When PONV occurred, despite antiemetic prophylaxis, it was estimated that half of these patients would be treated with rescue therapy. The probability of readmission due to PONV was 0.0018%. The probability of adverse effects was 20% with droperidol and 10% with dolasetron. The probability of treatment of adverse effects was 50%. The probability of failure with rescue medications was 38% with metoclopramide and 15% with droperidol.
Measure of benefits used in the economic analysis The comparison of dolasetron with droperidol prophylaxis was analysed using a cost-minimisation technique because the estimated PONV outcomes were equivalent. When comparing prophylaxis with rescue therapy, the proportion of patients developing PONV and the risk of a significant adverse drug reaction were used as the measures of benefit.
Direct costs Direct costs were not discounted given the short time frame of the study (less than 1 year). Quantities and costs were reported separately. Direct costs reflected medical costs incurred due to prophylactic therapy with droperidol or dolasetron, treatment of PONV, and treatment of adverse reactions. The quantity/cost boundary adopted was that of a hospital. The estimation of quantities and costs was based on actual data. Acquisition costs for prophylactic therapy and agents used to treat adverse drug reactions were obtained from the Clinical Service Unit Pharmaceutical Sciences' drug distribution computer database. Costs for nursing labour were obtained from the hospital's Patient Costing Department. The price year was 1998.
Statistical analysis of costs Sensitivity analysis Univariate and multivariate sensitivity analyses were performed on the effectiveness and cost estimates.
Estimated benefits used in the economic analysis The proportion of patients who developed PONV after receiving prophylaxis with dolasetron and droperidol was 42% compared with 62% for patients not receiving prophylaxis. The risk of a significant adverse drug reaction in patients receiving prophylactic therapy with droperidol was two times greater than for patients receiving prophylaxis with dolasetron (20% and 10%, respectively).
Cost results The mean cost per patient was Can$28.08 with dolasetron, Can$26.88 with droperidol, and Can$26.92 with rescue therapy.
Synthesis of costs and benefits Droperidol prophylaxis dominated rescue therapy. Compared to rescue therapy, dolasetron resulted in an incremental cost-effectiveness of Can$5.82 per additional PONV-free patient. The mean costs per PONV-free patient were Can$48.41 with dolasetron, Can$46.34 with droperidol, and Can$70.83 with rescue therapy. Overall, prophylaxis with either dolasetron or droperidol was more cost-effective than rescue therapy. When compared with droperidol, dolasetron prophylaxis prevents one additional significant adverse event at an additional cost of Can$12 Can. These results were not sensitive to changes in probabilities and costs.
Authors' conclusions Dolasetron and droperidol given intra-operatively were more cost-effective than no prophylaxis for PONV in patients undergoing ambulatory gynaecologic surgery. The difference between the two agents was small and favoured droperidol. The model was robust to plausible changes in the parameters.
CRD COMMENTARY - Selection of comparators The rationale for the choice of the comparator was clear. You, as a user of the database, should verify whether these health technologies are relevant to your setting.
Validity of estimate of measure of benefit The effectiveness data used in the decision tree have been derived from, what may have been, a non-systematic review of the literature. The internal validity of the data derived from the literature cannot be fully assessed given the limited information provided about the review and the quality assessment of the primary studies. An important assumption made in the analysis was that the efficacy of droperidol and dolasetron were similar, which was justified by the fact that dolasetron and ondansetron appear to have a similar efficacy rate. Estimation of efficacy rates for the drugs and placebo was complicated by the varying definitions and detection techniques for nausea, vomiting, and overall response to therapy used in the literature. The results were only valid for surgical procedures which result in an incidence of PONV greater than 52%. The authors assumed that patients placed the same importance on the avoidance of PONV as they did on the avoidance of side-effects to anti-emetic therapy.
Validity of estimate of costs Only direct costs were considered. No indirect costs were included. Costs associated with treating extrapyramidal symptoms after the administration of droperidol were not considered. Cost estimates were derived from local sources and are unlikely to be generalisable to other settings.
Other issues Adequate comparisons with other relevant studies were made. The generalisability of the results to other settings or countries was not discussed. The authors do not appear to have presented their results selectively. The study enrolled patients undergoing ambulatory gynaecologic surgery and this was reflected in the authors' conclusions.
Implications of the study As there have been no published randomised, controlled trials comparing dolasetron with droperidol for prophylaxis of PONV, such an RCT should be the focus of future research. Future studies should compare different antiemetics used for the prevention of PONV in gynaecologic surgery such as metoclopramide, perphenazine, droperidol, ondansetron, and dolasetron.
Bibliographic details Frighetto L, Loewen P S, Dolman J, Marra C A. Cost-effectiveness of prophylactic dolasetron or droperidol vs rescue therapy in the prevention of PONV in ambulatory gynecologic surgery. Canadian Journal of Anesthesia 1999; 46(6): 536-543 Other publications of related interest 1. Tramer M R, Moore R A, Reynolds D J, McQuay H J. A quantitative systematic review of ondansetron in treatment of established postoperative nausea and vomiting. British Medical Journal 1997;314:1088-1092.
2. Tang J, Watcha M F, White P F. A comparison of costs and efficacy of ondansetron and droperidol as prophylactic antiemetic therapy for elective outpatient gynecologic procedures. Anesthesia & Analgesia 1996;83(2):304-313.
3. Domino K B, Anderson E A, Polissar N L, Posner K L. Comparative efficacy and safety of ondansetron, droperidol, and metoclopramide for preventing postoperative nausea and vomiting: a meta-analysis. Anesthesia & Analgesia 1999;88(6):1370-1379.
Indexing Status Subject indexing assigned by NLM MeSH Ambulatory Surgical Procedures /adverse effects; Antiemetics /administration & Canada; Cost-Benefit Analysis; Decision Support Techniques; Decision Trees; Droperidol /administration & Drug Costs; Female; Forecasting; Gynecologic Surgical Procedures /adverse effects; Humans; Indoles /administration & Injections, Intravenous; Intraoperative Care /economics; Metoclopramide /economics /therapeutic use; Postoperative Nausea and Vomiting /drug therapy /economics /prevention & Probability; Prochlorperazine /economics /therapeutic use; Quinolizines /administration & Sensitivity and Specificity; Treatment Outcome; control; dosage /adverse effects /economics /therapeutic use; dosage /adverse effects /economics /therapeutic use; dosage /adverse effects /economics /therapeutic use; dosage /adverse effects /economics /therapeutic use AccessionNumber 21999001179 Date bibliographic record published 30/06/2000 Date abstract record published 30/06/2000 |
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