The results of 27% of clinical trials on surgical techniques remain hidden according to a new study in The BMJ. Researchers from the UK searched for trials registered on the clinical trial register in 2008 and 2009 with the keyword “surgery”. They found 395 relevant trials from 39 countries on 6 continents; 314 of the trials were listed as complete. The researchers found published articles for 208 of the completed trials and results for a further 20 trials were posted on This means we still don’t know what was found in 86 or 27% of the surgery clinical trials.

When the researchers looked at the types of trials that were not published, they found that 43% of trials funded by industry were not published compared to 27% of trials not funded by industry.

The researchers also found that 81 of the 395 surgery trials were stopped early. They emailed the sponsors of those trials to ask for an explanation as to why each trial was stopped, the most common reasons were poor recruitment, lack of funding and negative results.

The researchers conclude that trials which never report results “represent a waste of research resources and raises ethical concerns regarding hidden clinical data and futile participation by patients.”

The researchers say that an ethical duty to report results should be incorporated into research funding agreements. In fact, this is just what the US medical research funding body, the National Institutes of Health (NIH), is proposing to do by only funding research which is registered and reports results. Read more about the NIH’s proposal and add your voice in support before 19th February 2015.