Prevalence, characteristics, and publication of discontinued randomized trials.

TitlePrevalence, characteristics, and publication of discontinued randomized trials.
Publication TypeJournal Article
Year of Publication2014
AuthorsKasenda, B, von Elm, E, You, J, Blümle, A, Tomonaga, Y, Saccilotto, R, Amstutz, A, Bengough, T, Meerpohl, JJ, Stegert, M, Tikkinen, KAO, Neumann, I, Carrasco-Labra, A, Faulhaber, M, Mulla, SM, Mertz, D, Akl, EA, Bassler, D, Busse, JW, Ferreira-Gonzalez, I, Lamontagne, F, Nordmann, A, Gloy, V, Raatz, H, Moja, L, Rosenthal, R, Ebrahim, S, Schandelmaier, S, Xin, S, Vandvik, PO, Johnston, BC, Walter, MA, Burnand, B, Schwenkglenks, M, Hemkens, LG, Bucher, HC, Guyatt, GH, Briel, M
Date Published03/2014
ISSN0098-7484 (linking)
ISBN Number1538-3598 (Electronic)
KeywordsCanada, Cohort Studies, Ethics Committees, Research, Germany, Humans, Odds Ratio, Patient Selection, Publication Bias, Randomized Controlled Trials as Topic, Retrospective Studies, Switzerland

IMPORTANCE: The discontinuation of randomized clinical trials (RCTs) raises ethical concerns and often wastes scarce research resources. The epidemiology of discontinued RCTs, however, remains unclear.

OBJECTIVES: To determine the prevalence, characteristics, and publication history of discontinued RCTs and to investigate factors associated with RCT discontinuation due to poor recruitment and with nonpublication.

DESIGN AND SETTING: Retrospective cohort of RCTs based on archived protocols approved by 6 research ethics committees in Switzerland, Germany, and Canada between 2000 and 2003. We recorded trial characteristics and planned recruitment from included protocols. Last follow-up of RCTs was April 27, 2013.

MAIN OUTCOMES AND MEASURES: Completion status, reported reasons for discontinuation, and publication status of RCTs as determined by correspondence with the research ethics committees, literature searches, and investigator surveys.

RESULTS: After a median follow-up of 11.6 years (range, 8.8-12.6 years), 253 of 1017 included RCTs were discontinued (24.9% [95% CI, 22.3%-27.6%]). Only 96 of 253 discontinuations (37.9% [95% CI, 32.0%-44.3%]) were reported to ethics committees. The most frequent reason for discontinuation was poor recruitment (101/1017; 9.9% [95% CI, 8.2%-12.0%]). In multivariable analysis, industry sponsorship vs investigator sponsorship (8.4% vs 26.5%; odds ratio [OR], 0.25 [95% CI, 0.15-0.43]; P < .001) and a larger planned sample size in increments of 100 (-0.7%; OR, 0.96 [95% CI, 0.92-1.00]; P = .04) were associated with lower rates of discontinuation due to poor recruitment. Discontinued trials were more likely to remain unpublished than completed trials (55.1% vs 33.6%; OR, 3.19 [95% CI, 2.29-4.43]; P < .001).

CONCLUSIONS AND RELEVANCE: In this sample of trials based on RCT protocols from 6 research ethics committees, discontinuation was common, with poor recruitment being the most frequently reported reason. Greater efforts are needed to ensure the reporting of trial discontinuation to research ethics committees and the publication of results of discontinued trials.


Publication types: Journal Article ; Research Support, Non-U.S. Gov't Publication Status: ppublish

Alternate URL



Alternate JournalJAMA
Citation Key / SERVAL ID3547
Peer reviewRefereed
PubMed ID24618966
Grant List / / Canadian Institutes of Health Research / Canada


Institute of Social and Preventive Medicine
Route de la Corniche 10, 1010 Lausanne - Switzerland
+41 21 314 72 72 |

Go to top