Article type
Year
Abstract
Background: Systematic reviews require the identification of ongoing trials. This presentation reflects on our experiences with a systematic review that was originally completed in 2001 and substantially updated in 2005.
Methods: In 2001 we conducted a systematic review on the use of the anti-anaemia drug erythropoietin in cancer patients. Published trials were identified in MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL). Relevant conference proceedings were searched for abstracts. Ongoing trials were identified in internet databases. The searches for paper publications, abstracts and ongoing trials were repeated in 2005.
Results: Literature searches yielded 1592 references for the 2001 Cochrane review and 1859 references for the update in 2005. A total of 57 randomized controlled trials with 9353 patients were included, of which 27 studies with 3287 participants were analysed in the first review and another 30 studies with 6066 participants were included for the update. For the first Cochrane review 24 trials had been identified as ongoing. Three were completed and published in the meantime and included in the updated meta-analysis. Five of the ongoing trials have been published as abstracts or full text publications but had to be excluded since they did not meet our inclusion criteria (decision was made based on the newly available information). Thus, of the original 24 ongoing studies, 16 trials remain in the ongoing studies section. Of the 30 completed trials identified in the update, only three had been identified as an ongoing study in the first review. This means therefore that 27 of the completed trials in the update, had not been reported in the ongoing trials databases that were searched in 2001.
Conclusions: There is a substantial body of research underway that is not recorded in ongoing trials databases. Central registration of all ongoing studies is highly demanded.
Methods: In 2001 we conducted a systematic review on the use of the anti-anaemia drug erythropoietin in cancer patients. Published trials were identified in MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL). Relevant conference proceedings were searched for abstracts. Ongoing trials were identified in internet databases. The searches for paper publications, abstracts and ongoing trials were repeated in 2005.
Results: Literature searches yielded 1592 references for the 2001 Cochrane review and 1859 references for the update in 2005. A total of 57 randomized controlled trials with 9353 patients were included, of which 27 studies with 3287 participants were analysed in the first review and another 30 studies with 6066 participants were included for the update. For the first Cochrane review 24 trials had been identified as ongoing. Three were completed and published in the meantime and included in the updated meta-analysis. Five of the ongoing trials have been published as abstracts or full text publications but had to be excluded since they did not meet our inclusion criteria (decision was made based on the newly available information). Thus, of the original 24 ongoing studies, 16 trials remain in the ongoing studies section. Of the 30 completed trials identified in the update, only three had been identified as an ongoing study in the first review. This means therefore that 27 of the completed trials in the update, had not been reported in the ongoing trials databases that were searched in 2001.
Conclusions: There is a substantial body of research underway that is not recorded in ongoing trials databases. Central registration of all ongoing studies is highly demanded.