Objectives: The aim of this study was to compare Bayesian methods with the standard methods that are used for evidence-based policy making.

Methods: We performed a Bayesian reanalysis of the data underlying a reimbursement advice by the Dutch National Health Insurance Board (CVZ) regarding the anti-diabetic drug exenatide (an alternative to insulin). We synthesized evidence from various sources that was available when the CVZ advice was drafted: expert opinion (as elicited from internists), experimental data (from direct comparison studies), and observational data. Subsequently, the original frequentist results and the results from the Bayesian reanalysis were compared in terms of outcomes and interpretations. These results were presented in a meeting with staff from CVZ, whose opinions about the usefulness of a Bayesian approach were assessed using a questionnaire.

Results: The Bayesian approach yields outcomes that summarize different pieces of evidence, which would have been difficult to obtain otherwise. Moreover, there are conceptual differences, and the Bayesian approach allows for determining probabilities of clinically relevant differences. The staff at CVZ were fairly positive with respect to the use of Bayesian methods, although practical barriers were also seen as important.

Conclusions: The Bayesian outcomes are different and could be more suited to the informational needs of policy makers. The response from staff at CVZ provides some support for this statement, but more research at the interface of science and policy is needed.

The French healthcare system combines freedom of medical practice with nationwide social security. It is compulsory for every legal resident. A range of public and private institutions provide care, and patients have free access to physicians. The health coverage system is characterized by solidarity and universal responsibility. Although the French system is highly regulated, funding of health-related expenses is a chronic social problem. Since the 1996 healthcare reform, the national objective for reimbursed healthcare expenditures is voted by the parliament, and the annual increase of hospital funding is controlled at the regional level. An agency for hospitals has been established in every region, and it quantifies needs indexes for future equipment and beds. However, establishing appropriate reference ratios based on objective assessment is difficult. The idea of basing policy and practice decisions on objective assessment grew for years, until the National Agency for the Development of Medical Evaluation was established in 1989. The 1996 healthcare reform expanded this agency to encompass hospital accreditation and renamed it the National Agency for Accreditation and Evaluation in Health. In March 1999, the National Agency for Health Products was established. It controls the safety of medical products and evaluates products' medical benefits before reimbursement decisions. Health technology assessment is now related to virtually every health policy process in France, and its role increases continually.