Cost-utility analyses of clinical preventive services: published ratios, 1976-1997

Cost-effectiveness analyses of clinical preventive services are a potential means to aid public health resource allocation. Cost-utility analysis (CUA) is a specific form of cost-effectiveness analysis where results are expressed in terms of cost per quality-adjusted life year (QALY) gained. To increase the transparency and comparability of CUAs, standardization of methods has been recommended.

The purposes of this study were as follows: (1) identify published articles with original CUAs of primary and secondary clinical preventive services, (2) summarize the ratios found in these analyses, (3) identify articles employing comparable methods, and (4) explore analytic methods employed over time.

As part of a larger study we conducted a comprehensive search of published CUAs in the area of clinical preventive services and systematically collected data on the results of the analyses and analytic methods employed. Cost-effectiveness ratios were standardized and organized into a table.

We found 50 CUAs pertaining to clinical preventive services (primary, n=22, 44%; and secondary, n=28, 56%) and 174 cost-effectiveness ratios. These ratios ranged from cost-savings up to $27,000,000/QALY, with a median of $14,000/QALY. Only three (6%) of the CUAs met minimum reference case requirements. There was no apparent improvement of methods over time.

Immunizations and chemoprophylaxis have the most favorable cost-effectiveness ratios, and preventive services are more cost-effective when targeted at high-risk populations. However, there is wide variation in the methods used in these analyses. This study allows us to define where improvements in methodologic rigor need to occur, provides a base-line for future audits, and highlights disease areas in clinical preventive services that have been omitted or underevaluated.