An Analysis of the Rates of Discontinuation and Non-publication of Chronic Pain Clinical Trials

Introduction: It is well documented that aggressive disinformation marketing by the pharmaceutical industry contributed to the opioid epidemic, but another factor that is often overlooked, is the nonpublication and discontinuation of randomized clinical trials (RCTs). All publications, with or without statistical significance, yield beneficial insight and prevent research waste. The primary objective of this cross-sectional analysis is to evaluate the rate of discontinuation or nonpublication of RCTs involving patients with chronic pain.

Methods: Using ClinicalTrials.gov, a sample was derived on October 5th, 2020, which included clinical trials pertaining to chronic pain. Trials were analyzed for publication status and completion status of each trial. If information was unavailable on the trial registry database, or could not be allocated through a systematic search, the corresponding trialist was contacted and data points were gathered.

Results: In our final analysis of the 408 RCTs, we found that 281 (68.9%) were published in a peerreviewed journal and 127 (31.1%) were unpublished trials. Of 112 discontinued trials, 59 (52.7%) reached publication. In addition, 221 of 296 completed trials (74.7%) were published, and 75 (25.3%) remained unpublished after trial completion. Clinical trials funded by non-industry sponsors were more likely to reach publication than industry-funded clinical trials ((unadjusted odds ratio (uOR) 1.86 [95% CI, 1.18-2.95]; adjusted odds ratio (aOR) 3.01 [95% CI, 1.76-5.14]). Pharmaceutical intervention clinical trials were more likely to be completed and more likely to reach publication, than medical device intervention clinical trials (uOR 3.46 [95% CI, 1.74-6.87]; aOR 2.12 [95% CI, 1.05-4.33], and uOR 3.22 [95% CI, 1.62- 6.40]; aOR 2.55 [95% CI, 1.23-5.29] respectively).

Conclusion: Chronic pain clinical trials that are funded by industry sources are more likely to be completed than trials funded by all other sources; however, industry funded chronic pain clinical trials are far less likely to be published than chronic pain clinical trials funded by non-industry sources. This data is indicative of the overarching narrative of the pharmaceutical pain industry over the last two decades; namely, that this industry repeatedly suppressed information that was not conducive to their bottom line while promoting disinformation that was beneficial to them. In order to regain the trust of the public, it is imperative that the pharmaceutical pain industry increases transparency in reporting their research.