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Using the NHLBI data repository, 370 investigators requested data from at least one clinical trial -- 51% of them trials on cardiovascular prevention and treatment. Requests were largely for post hoc secondary analysis (72%); a minority of requests were initiated for analytic or statistical approaches to clinical trials (9%) and meta-analyses (7%).
More than half of investigators (53%) made their requests in the last 4.4 years of the study period (January 2000 to May 2016), "indicating an increasing demand for trial data that has outpaced acquisition," wrote Sean A. Coady, MS, MA, of the NHLBI in Bethesda, Md., and colleagues. "In contrast, demand for observational data has increased in a pattern more directly proportional to time."
The NHLBI's study was published online in the New England Journal of Medicine -- the same journal whose editor-in-chief, Jeffrey Drazen, MD, once suggested that sharing data will enable 'research parasites' to steal from the data gatherers or try to disprove what the investigators originally showed.
After a firestorm on social media, Drazen walked it back and advocated data sharing.
Now, Coady's group says, data requests from 47 trials led to the publication of 277 new articles. Half of the 224 articles linked to the InCites database ranked in the top 34% for cumulative citations, perhaps indicative of a substantial contribution to the literature.
"The results of this study of the NHLBI data repository suggest that release of clinical trial data for wide sharing can contribute to the scientific community in multiple ways, including increasing the transparency of findings, examining new hypothesis-generating questions, providing pilot data for grant submissions, testing statistical methods, performing meta-analyses, and developing prediction algorithms."
Of 172 requests with online project descriptions, just two were intended for re-analysis of primary outcome findings.
"There are limitations in our study that should be acknowledged," Coady et al wrote. "The NHLBI data repository consists primarily of data from large trials or trials from large clinical networks, and the results of widely sharing these data may not be generalizable to all trials ... Abstracts and aims were reviewed and projects were excluded if there was no interaction with human participants, the number of participants was less than 500, the project was principally genomic, the project was ancillary to another study, or the project end date was 2018 or later.
"Of 133 R01s and 81 U01s involving a clinical trial, 38 R01s and 35 U01s were potentially eligible, with only 2 R01s (5%) and 10 U01s (29%) currently in the repository or with known plans to submit."