Analytical approach:
The economic evaluation was based on a budget impact model, with a hypothetical population of 1,000 pregnant women, who were followed-up from 12 weeks gestation to term (40 weeks gestation). The authors stated that the analysis was carried out from the perspective of the UK NHS.
Effectiveness data:
The clinical data were from a selection of relevant studies. The sensitivity and specificity of the two diagnostic approaches were the key inputs for the model. The accuracy of the new pre-eclampsia test was from a published clinical trial. The accuracy of standard practice was from a pooled synthesis of data from various sources analysing each test individually. Disease incidence was from studies reporting UK data. Expert opinion was used for the clinical treatment patterns for pre-eclampsia.
Monetary benefit and utility valuations:
Not considered.
Measure of benefit:
The numbers of false-positive and false-negative results were the primary clinical outcomes.
Cost data:
The economic analysis included the costs of drugs, office visits, physical exams, regular blood pressure checks, blood and urine tests, cardiotocography and hospital stays for day assessment, intensive care, in-patient monitoring, and delivery or termination of pregnancy. The resource quantities were from published databases and interviews with 10 UK experts, five laboratory managers, and five payers. The unit costs were from official UK sources, such the British National Formulary, the NHS Payment by Results Database, and published literature. The cost of the in vitro test was provided by the manufacturer. All costs were in UK pounds sterling (£).
Analysis of uncertainty:
Univariate sensitivity analyses were carried out to assess the impact of variations in the pre-eclampsia incidence, the sensitivity and specificity of standard tests, the proportion of patients identified as at high-risk of pre-eclampsia, and the cost of the new test. The ranges of values for these analyses were assumed by the authors.