Objectives: This study proposes the method requirements for a valid costing study in anesthesia to allow differences to be identified between treatments and uses these method requirements to design and conduct a robust costing study.
Methods: A prospective, patient-based costing study was carried out in adult and pediatric day surgery in the United Kingdom. The perspective was that of the National Health Service and the patient. Data were collected for each patient until 7 days after hospital discharge.
Results: Data were collected for 1063 adults and 322 children undergoing day surgery between October 1999 and January 2001. Statistically significant differences were found only between variable costs, which accounted for 11.4 percent and 9.0 percent of adult and pediatric costs, respectively. There were no differences in length of stay, fixed costs, or semi-fixed costs. Differences were not found in total costs in adults but were found in children. By day 7, postdischarge primary and secondary care costs were not different between groups in either study. No differences were found in costs to patients or parents.
Conclusions: The use of prospective, patient-based cost data enabled the detection of differences in variable costs between difference anesthetic regimens in day surgery. The stochastic nature of the data provided a measure of variability around mean cost estimates. Practice patterns in the study reflected normal practice in the United Kingdom so the costing data have direct clinical relevance. The use of different anesthetic agents only affected variable costs and had no effect on larger cost drivers such as length of stay or staff input.