Agreement of Primary Outcomes in Chiropractic-Related Clinical Trials Registered in clinicaltrials.gov with Corresponding Publication.

Abstract

Introduction:Previous analysis of registered clinical trials has found a disappointing number of study protocols result in publications which change what the registered a priori primary outcome measure is. Likewise, there is a disappointing rate of unpublished trials. Similar research has not been published on chiropractic-related studies. Primarily this investigation determined if reported primary outcomes in chiropractic-related clinical trials registered in clinicaltrials.gov match their published results. Secondarily, other outcome measures and publication status are assessed.Methodology:Clinicaltrials.gov was searched for chiropractic-related trials, using the search terms “chiropractic”, “chiropractor”, and having a completed status. Publication status was determined by searching PubMed (pubmed.gov), Index to Chiropractic Literature (chiroindex.org), and Google Scholar (scholar.google.com) through 29 May 2020. If the study was published, outcome measures were compared between the clinicaltrials.gov entry and the published paper to assess for consistency by two independent investigators. If there was disagreement between investigators, a third evaluated the data and decided if the published paper agreed with the clinicaltrials.gov entry.Results:Within clinicaltrials.gov 171 chiropractic-related protocols were identified. Twenty-five (25) had results posted and 102 were published. Twenty-nine of those entries produced multiple papers consisting of protocols, plot/feasibility studies, clinical trials, and poster presentations. Of the 102 studies published, 92 (90.2%) had agreement between their primary outcome and the listed entry on clinicaltrials.gov and 82 (80.4%) agreed with the secondary outcomes in the registered protocol. Entries on clinicaltrials.gov had a 59.6% (102/171) publication rate and a 14.6% (25/171) rate of displaying their results. Conclusion:A modest rate of agreement (90.2%) between clinicaltrails.gov entries and the 102 published papers (59.6% publication rate) were found. While chiropractic-related clinical trials are fewer in number compared to medical trials, chiropractic-related research has a substantially better rate of primary and secondary outcome concordance with registered protocols and a better publication rate. Investigators need to continue to upload results onto clinicaltrials.gov and seek publication regardless of the study findings. It is important to publish negative results so as not to introduce publication bias into systematic reviews and meta-analyses. Both positive and negative findings are important when evaluating treatments and determining the best care for patients.