The analysis was based on a short-term decision tree followed by a Markov model, with a 10-year horizon. The authors did not explicitly state the perspective adopted.
The clinical data came from selected published sources. The key clinical input was the efficacy of the two strategies and this came from a retrospective cohort study, with 222 patients at a single centre over two different periods of time. There were 131 patients (mean age 44.5 years ±11.8; 64.1% men) in the three-month prophylaxis group and 91 patients (mean age 45.8 years ±12.3; 68.1% men) in the six-month prophylaxis group. Multivariate analysis was undertaken to account for potential baseline differences between groups. Patients were followed-up for one year. The long-term transition probabilities were from US sources, such as the US Renal Data System and Organ Procurement and Transplantation Network, and the Scientific Registry of Transplant Recipients.
Monetary benefit and utility valuations:
The utility values were from published studies, the details of which were not given.
Measure of benefit:
The summary benefit measures were the probability of cytomegalovirus infection and disease in the cost-effectiveness analysis and quality-adjusted life-years (QALYs) in the cost-utility analysis.
The economic analysis included the direct costs (prophylaxis, diagnosis, treatment of cytomegalovirus disease and infection, and expenses associated with maintaining a patient who had a functioning graft or a patient who had lost graft function and had returned to dialysis) and productivity costs (opportunity costs, such as those of productivity lost due to absence from work). The costs and resource quantities were from the retrospective cohort study and other data were from published sources, such as Centers for Medicare and Medicaid Services (CMS) prices. Assumptions were made for productivity costs. All costs were in US dollars ($) and the price year was 2007. A 5% annual discount rate was used for indirect costs that were incurred over the long-term.
Analysis of uncertainty:
Two-way sensitivity analyses were carried out by varying the costs of hospital services and prophylaxis medications, for arbitrary ranges of values. Other key model inputs were also varied in one-way sensitivity analyses.