Registration practices for observational studies on indicated low adherence

Stefania Boccia, Kenneth J. Rothman, Nikola Panic, Maria Elena Flacco, Annalisa Rosso, Roberta Pastorino, Lamberto Manzoli, Carlo La Vecchia, Paolo Villari, Paolo Boffetta, Walter Ricciardi, John P.A. Ioannidis

Research output: Contribution to journalArticle

23 Citations (Scopus)


OBJECTIVE: The study aims to assess the status of registration of observational studies. STUDY DESIGN AND SETTING: We identified studies on cancer research with prospective recruitment of participants that were registered from February 2000 to December 2011 in We recorded the dates of registration and start of recruitment, outcomes, and description of statistical method. We searched for publications corresponding to the registered studies through May 31, 2014. RESULTS: One thousand one hundred nine registered studies were eligible. Primary and secondary outcomes were reported in 809 (73.0%) and 464 (41.8%) of them. The date of registration preceded the month of the study start in 145 (13.8%) and coincided in 205 (19.5%). A total of 151 publications from 120 (10.8%) registered studies were identified. In 2 (33.3%) of the 6 publications where reported that the study started recruitment after registration, and in 9 (50.0%) of 18 publications where reported the same date for registration and start of recruitment, the articles showed that the study had actually started recruiting before registration. CONCLUSION: During the period reviewed, few observational studies have been registered. Registration usually occurred after the study started, and prespecification of outcomes and statistical analysis rarely occurred.
Original languageEnglish
Pages (from-to)176-182
Number of pages7
JournalJournal of Clinical Epidemiology
Publication statusPublished - 2016


  • Cancer protocol registration
  • Outcome reporting bias
  • Protocol registration
  • Registration of observational studies
  • Registration study records


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