Background: Prior research suggests there may be a need for reviewing clinicaltrials.gov for evidence. Subsequent reporting of results from trials on clinicaltrials.gov is between 40-50% with results published in peer-reviewed journals. This raises concern for reporting biases.

Objective: To determine: 1) if review of clinicaltrials.gov will result in the same quality evidence (randomised-controlled trials (RCTs)) found as compared to conducting traditional literature reviews; and, 2) if ClinicalTrials.gov searches will populate evidence not published in peer-reviewed journals and should therefore be reviewed by guideline developers.

Methods: We focused our comparison on the third edition of the hip and groin guidelines developed by the American College of Occupational and Environmental Medicine (ACOEM) in 2013. We first replicated our original literature searches on clinicaltrials.gov for the following treatments: herbal preparations (HP), acupuncture, low-level laser therapy (LLT), and magnetic stimulation (MS). The same search terms and parameters were used as in 2013. We then reviewed trials registered on clinicaltrials.gov for each of the four treatments that were not published in a peer-reviewed journal.

Results: Our original search for ACOEM’s 3rd edition included a total of 28 RCTs for all 4 treatments (N=19 HP, N=9 acupuncture, N=0 LLT, N=0 MS). We applied the same search parameters as our original searches but were unable to locate any of these trials on clinicaltrials.gov. Replicating the searches for all four treatments on clinicaltrials.gov resulted in 26 registered trials (N=7 HP, N=15 acupuncture, N=0 LLT, N=4 MS) out of which 82.1% did not have any results published in a peer-reviewed journal.

Conclusion: None of our original evidence was found on clinicaltrials.gov. More alarmingly, we found a total of 26 registered trials on clinicaltrials.gov out of which 82.1% did not have results published in a peer-reviewed journal. Given the stark discrepancies between our traditional searches and searches on clinicaltrials.gov we believe there is a need to include clinicaltrials.gov in our search methodology.