Estimating costs in a cost-effectiveness analysis

Abstract

Objectives: Since the results of a cost-effectiveness analysis (CEA) are generally sensitive to the input cost parameter values selected for difference disease-related outcomes a systematic approach should be used to derive these estimates as suggested in HTA guidance. To determine the extent to which a systematic approach was used to select disease-related cost estimates for inclusion in CEAs for new hepatitis C treatments.

Methods: A systematic literature review of primary costing studies and of the cost data used in published CEAs was performed for different stages of liver disease for those with chronic hepatitis C infection. The process described in the cost-effectiveness analyses by which they selected the input base-case cost values as well as the ranges used in the sensitivity analyses was reviewed to determine whether or not a systematic approach was used to identify primary cost studies and whether or not the a rationale was supplied for the values selected.

Results: The hepatitis C systematic review focused on US costs and cost-effectiveness analyses. In most of the hepatitis C cost-effectiveness analyses, the cost estimates used were either taken directly or derived from recent primary cost studies. However, a systematic review was not generally used to identify the recent primary cost studies. In addition, the method used to adapt the data from the selected studies for use in the CEA was either not explained and/or appeared to be incorrect in some of the CEAs. In most of the CEAs, sensitivity analyses assumed arbitrary ranges for the cost estimates (for example, plus or minus 50%) rather than using ranges from alternative cost studies.

Conclusions: Very little detail is provided in published CEAs about the methods used to identify primary disease-related cost studies and a rationale for selection of the costs is generally not provided.