Searching for evidence for health technology assessments (HTAs) is time-consuming because the evidence identified must be a reliable basis for robust assessment results: The scientific knowledge about the benefits and harms for patients must be completely available. This is why IQWiG's in-formation specialists regularly review the effectiveness and efficiency of information retrieval con-ducted for the Institute's HTAs.
In an IQWiG working paper, the search portal "International Clinical Trials Registry Platform" (IC-TRP), a WHO meta-registry, was systematically analysed for its relevance to information retrieval at IQWiG. The key question was: "Which studies of drugs and non-drug interventions included in IQWiG assessments since 2004 can only be found in the ICTRP Search Portal and not in regulatory study registries, i.e. ClinicalTrials.gov (CT.gov) of the US National Institute of Health (NIH) or the EU Clinical Trials Register (EU-CTR) of the European Medicines Agency (EMA)?"
Conclusion: Searching for drug studies in the ICTRP Search Portal is dispensable, because hardly any studies (only 1 to 2%) are retrieved that are not included in CT.gov or EU-CTR. Moreover, the very low number of unique hits did not affect the results of IQWiG's drug assessments. The situation was different when searching for studies of non-drug interventions: The studies included were often reported in only 1 of the 3 study registries mentioned above, and about a third of the rele-vant registry entries were provided by the ICTRP registry. Therefore, searching the ICTRP Search Portal is essential for assessments of non-drug interventions.
Evidence is not an end in itself: as much as necessary
Siw Waffenschmidt, Head of IQWiG's Information Management Department notes: "Now we know: The legal obligation to register clinical studies, as in the USA, enables productive, reliable and efficient searches for evidence on drug studies. This means that there is no need to search the IC-TRP Search Portal, which also means less work for everyone involved in drug assessments, includ-ing the pharmaceutical industry. This is because searching for and screening ICTRP registry entries is particularly time-consuming. IQWiG will also strive to ensure efficient information management for future European HTAs. Our motto is: 'Search completely, but efficiently!'"
In contrast, IQWiG's evaluation confirms that the ICTRP Search Portal is essential when searching for studies of drug interventions, as not all of these studies are registered – and if they are, they are sometimes registered in one registry, and sometimes in another. This is because there is no legal obligation to do so. For this reason, it is still essential to invest more effort in information retrieval for HTAs of non-drug interventions.
Procedure of report production
This report was prepared as a working paper under the general commission granted to IQWiG by the Federal Joint Committee (G-BA) in December 2004 to strengthen the Institute's scientific inde-pendence. The general commission enables IQWiG to select topics and answer research questions independently. IQWiG sent the working paper "Evaluation of regular searches in the ICTRP Search Portal" to the G-BA on 8 March 2024.
