Validity of Health Technology Assessements(HTA)

Article type
Authors
Faessler M, Awa A, Kajnar H, Porzsolt F
Abstract
Background: Health technology assessments (HTA) may have considerable impact on decisions in health care policy. Therefore, it is essential that the quality requirements for such reports are met i.e. the question of the HTA has to be specified, the literature search has to be complete, only studies which meet certain quality criteria can be included in the HTA, and finally the results of the scientific analysis have to be reported adequately.

Objectives: In this paper we examine the validity of health technology assessments (HTA). We describe a strategy to detect lacks and improve the quality of reporting.

Methods: The following method was applied to two HTA reports on the treatment of hepatitis C, one prepared on behalf of the UK National Institute of Clinical Excellence (NICE) and the other by the Deutsches Institut fuer Medizinische Dokumentation und Information (DIMDI).

First, the homogeneity of the question was checked at different sensitive points of the HTA reports i.e. title, summary, end of introduction, results/ discussion. Second, the key papers of the HTA report were identified. Third, the key papers were critically appraised. The critical appraisal of the individual papers included the homogeneity of the question at different sensi-tive points of the papers, the description of the ideal study design, the comparison of the ideal study design with the applied study design, and finally the application of the validity criteria as described by Sackett [1] and the Evidence-based medicine working group.

Results: The criteria of homogeneity of the study question was met in both HTA reports which were both based on the same two key papers. In both key papers the study questions were homoge-neous throughout all sensitive points. The design of the studies was adequate but not the com-pletion as several of the validity criteria were not met (e.g. randomisation, blinding procedure, inclusion of all patients in the evaluation, intention-to-treat analysis).

Conclusions: The authors of both health technology assessment (HTA) reports conclude that the combina-tion of peginterferon and ribavirin is superior to interferon and ribavirin. We claim that this conclusion is not justified due to lack of validity of the key papers. Some of the deficiencies were described in the results and/or discussion of the HTA reports. These sections of the re-port are preferably read by scientists. However, none of these deficiencies are described in the summaries or conclusions of the HTA report which is preferably read by politicians.

The validity of a HTA report should be considered sufficient only if both, strengths and weaknesses of the report are expressed in its presentation board , the summary.

References: 1. Sackett DL, Straus SE, Richardson WS, Rosenberg W, Haynes RB. Evidence-based medicine, how to practice and teach EBM, 2nd ed. Edinburgh, London, New York, Philadelphia, St. Louis, Sydney, Toronto: Churchill Livingstone; 2000.