Marco Knelangen1, Elke Hausner2, Maria-Inti Metzendorf3, Sibylle Sturtz4, Siw Waffenschmidt2. 1. Information Management Unit, Institute for Quality and Efficiency in Health Care (IQWiG), Im Mediapark 8, 50670 Cologne, Germany. Electronic address: marco.knelangen@iqwig.de. 2. Information Management Unit, Institute for Quality and Efficiency in Health Care (IQWiG), Im Mediapark 8, 50670 Cologne, Germany. 3. Cochrane Metabolic and Endocrine Disorders Group, Institute of General Practice, Medical Faculty of the Heinrich-Heine-University, Moorenstr. 5, 40225 Düsseldorf, Germany. 4. Department of Medical Biometry, Institute for Quality and Efficiency in Health Care (IQWiG), Im Mediapark 8, 50670 Cologne, Germany.
Abstract
OBJECTIVES: To analyze the availability of randomized controlled trials (RCTs) of new drugs in trial registries and to develop and test different search strategies in ClinicalTrials.gov (CT.gov), the EU Clinical Trials Register (EU-CTR), and the International Clinical Trials Registry Platform (ICTRP). STUDY DESIGN AND SETTING: Information from dossiers submitted by pharmaceutical companies was analyzed regarding the registration of the included RCTs in CT.gov, EU-CTR and ICTRP; different search strategies were developed and tested to determine performance. RESULTS: A total of 192 (95%) of 203 RCTs on newly approved drugs were registered in CT.gov; the 11 nonregistered trials were completed before 2005 or represented non-RCTs. Simple searches for RCTs on 18 new drugs using the generic drug name yielded a sensitivity of 94% in CT.gov (EU-CTR: 71%; ICTRP: 60%). The main reason for study nondetection was the sole use of the drug code in the registry entries. Simple searches for RCTs on 13 conditions using reasonably inferred search terms yielded a sensitivity of 100% in CT.gov. CONCLUSION: Almost all relevant RCTs on newly approved drugs will probably be identified in CT.gov alone. A sensitive search in CT.gov can be conducted using single search terms. The searches in ICTRP and EU-CTR should include several search terms (e.g., derived via text analysis).
OBJECTIVES: To analyze the availability of randomized controlled trials (RCTs) of new drugs in trial registries and to develop and test different search strategies in ClinicalTrials.gov (CT.gov), the EU Clinical Trials Register (EU-CTR), and the International Clinical Trials Registry Platform (ICTRP). STUDY DESIGN AND SETTING: Information from dossiers submitted by pharmaceutical companies was analyzed regarding the registration of the included RCTs in CT.gov, EU-CTR and ICTRP; different search strategies were developed and tested to determine performance. RESULTS: A total of 192 (95%) of 203 RCTs on newly approved drugs were registered in CT.gov; the 11 nonregistered trials were completed before 2005 or represented non-RCTs. Simple searches for RCTs on 18 new drugs using the generic drug name yielded a sensitivity of 94% in CT.gov (EU-CTR: 71%; ICTRP: 60%). The main reason for study nondetection was the sole use of the drug code in the registry entries. Simple searches for RCTs on 13 conditions using reasonably inferred search terms yielded a sensitivity of 100% in CT.gov. CONCLUSION: Almost all relevant RCTs on newly approved drugs will probably be identified in CT.gov alone. A sensitive search in CT.gov can be conducted using single search terms. The searches in ICTRP and EU-CTR should include several search terms (e.g., derived via text analysis).