Analysis of articles directly related to randomized trials finds poor protocol availability and inconsistent linking of articles

Abstract

Interpreting a randomised trial requires access to more than the main results paper. We aimed to determine the: 1) proportion of trials referring to the protocol in the trial report and their accessibility; 2) proportion of protocols accessible from trial registry entry and by trial registration number search; and 3) types of additional publications associated with trial reports. Study Design and Setting:A previously-gathered sample of randomised trials of nonpharmacological interventions published in 2009 was used. Trial reports and registry entries were searched for protocol mentions and obtained when possible. Related publications were identified using citation searching.Results: Of 133 trials, 96 (72%) mentioned the protocol within the report, 61 (64%) contained details about protocol acquisition, with 48 (36%) protocols obtainable. Of the 129 registered trials, 32 (25%) had protocols obtainable from registry entry. Citation tracking identified 1030 related publications; secondary analyses and qualitative studies most common. Conclusion:Trial protocols facilitate good trial conduct and interpretation. However, they are often not linked to the main report or registry and can be difficult to obtain. Many trials have related publications which are inconsistently linked. Trial registries and registration numbers could facilitate the threading of articles related to a trial, but currently do not.

PRISMA 2020 explanation and elaboration: updated guidance and exemplars for reporting systematic reviews

“…Reporting registration information also facilitates linking of publications related to the same systematic review (such as when a review is presented at a conference and published in a journal). 154 Essential elements…”

“…This allows readers to compare what was pre-specified with what was eventually reported in the review and decide if any deviations may have introduced bias. Reporting registration information also facilitates linking of publications related to the same systematic review (such as when a review is presented at a conference and published in a journal) 154…”

A longitudinal assessment of trial protocols approved by research ethics committees: The Adherance to SPIrit REcommendations in the UK (ASPIRE-UK) study

“…In our sample, only 6% of protocols clarified who will have access to the final study protocol. Hence, it is important that not only the completeness of reporting of study protocols is improved, but also the public sharing of protocols is actively promoted [ 26 ] (or even enforced in parallel by journals publishing the results). Other important aspects to increase transparency include increasing the rate of registered trials and published trials which we have assessed in the frame of the ASPIRE project [ 17 ] and published in a separate sub-study [ 19 , 27 ].…”

A meta-research study of randomized controlled trials found infrequent and delayed availability of protocols

“…Although the benefits of making protocols publicly available are well established, data quantifying their avail-ability and the timing of their availability are limited to three studies [6,24,25]. Sender et al [6] primarily focused on nonpharmacologic trials, Lucey et al [24] only included RCTs that were submitted to the Lancet, and Spence et al [25] only included RCTs whose results were only published in high-impact journals [25]. Overall, there is limited generalizability concerning these findings [6,24].…”

“…Sender et al [6] primarily focused on nonpharmacologic trials, Lucey et al [24] only included RCTs that were submitted to the Lancet, and Spence et al [25] only included RCTs whose results were only published in high-impact journals [25]. Overall, there is limited generalizability concerning these findings [6,24].…”