Measuring costs in cost-utility analyses. Variations in the literature

Although cost-utility analysis (CUA) has been recommended by some experts as the preferred technique for economic evaluation, there is controversy regarding what costs should be included and how they should be measured. The purpose of this study was to: a) identify the cost components that have been included in published CUAs; b) catalogue the sources of valuation used; c) examine the methods employed for estimating costs; and d) explore whether methods have changed over time.

We conducted a comprehensive search of the published literature and systematically collected data on the cost estimation of CUAs. We audited the cost estimates in 228 CUAs.

In most studies (99%), analysts included some direct healthcare costs. However, the inclusion of direct non-healthcare and time costs (17%) was generally lacking, as was productivity costs (8%). Only 6% of studies considered future costs in added life-years. In general, we found little evidence of change in methods over time. The most frequently used source for valuation of healthcare services was published estimates (73%). Few studies obtained utilization data from RCTs (10%) or relied on other primary data (23%). About two-thirds of studies conducted sensitivity analyses on cost estimates.

We found wide variations in the estimation of costs in published CUAs. The study underscores the need for more uniformity and transparency in the field, and continued vigilance over cost estimates in CUAs on the part of analysts, reviewers, and journal editors.