Analytical approach:
This economic evaluation was based on a decision analytic model with a short time horizon corresponding to the recovery time and time for management of potential adverse events. The authors stated that the perspective of the health care provider was adopted.
Effectiveness data:
The clinical data were derived from a systematic review of the literature. The patient characteristics and most of the clinical data were derived from randomised controlled trials (RCTs). Standard meta-analytic techniques were used to estimate the differences between the two drugs. When required, a random effects model was used to pool the data and statistical tests were used to investigate the issue of heterogeneity among the data sources. A few assumptions were needed. The key clinical outcomes were the rate of successful sedations (with or without adverse events) and the recovery time (the time between the start of sedative infusion to full recovery).
Monetary benefit and utility valuations:
Not relevant.
Measure of benefit:
The summary benefit measure was the rate of successful sedations, which was defined as the ability to sedate a patient to a Ramsey Sedation Scale score greater than or equal to three, and successfully perform the medical procedure.
Cost data:
The health service costs were ED visits, drugs, personnel (physicians and nurses), management of adverse events, and treatment of PS failure. The costs were derived from multiple sources, including the St Paul’s Hospital Cost Model (which referred to a tertiary care teaching hospital), the British Columbia Nurses Union, the Health Employer’s Association of British Columbia, and the Vancouver General Hospital Practice Plan and Drug Formulary. The calculation of drug costs took into account wastage. The cost of consumable equipment was considered to be identical in the two treatments and was not considered. The resource use data were derived from published sources, which were mainly the RCTs used for the clinical data. All costs were in Canadian dollars (CAD) and the price year was 2006.
Analysis of uncertainty:
The issue of uncertainty was addressed by means of a probabilistic sensitivity analysis based on a Monte Carlo simulation. The details of this probabilistic approach were reported. A one-way sensitivity analysis was also undertaken on the key model inputs.