Time to publication for publicly funded clinical trials in Australia: an observational study

OBJECTIVE: To examine the length of time between receiving funding and publishing the protocol and main paper for randomised controlled trials. DESIGN: An observational study using survival analysis. SETTING: Publicly funded health and medical research in Australia. PARTICIPANTS: Randomised controlled trials funded by the National Health and Medical Research Council of Australia between 2008 and 2010. MAIN OUTCOME MEASURES: Time from funding to the protocol paper and main results paper. Multiple variable survival models examining whether study characteristics predicted publication times. RESULTS: We found 77 studies with a total funding of $A59 million. The median time to publication of the protocol paper was 6.4 years after funding (95% CI 4.1 to 8.1). The proportion with a published protocol paper 8 years after funding was 0.61 (95% CI 0.48 to 0.74). The median time to publication of the main results paper was 7.1 years after funding (95% CI 6.3 to 7.6). The proportion with a published main results paper 8 years after funding was 0.72 (95% CI 0.56 to 0.87). The HRs for how study characteristics might influence timing were generally close to one with narrow CIs, the notable exception was that a longer study length lengthened the time to the main paper (HR=0.62 per extra study year, 95% CI 0.43 to 0.89). CONCLUSIONS: Despite the widespread registration of clinical trials, there remain serious concerns of trial results not being published or being published with a long delay. We have found that these same concerns apply to protocol papers, which should be publishable soon after funding. Funding agencies could set a target of publishing the protocol paper within 18 months of funding.