Discontinuation and nonpublication analysis of chronic pain randomized controlled trials

The primary objective of this cross-sectional analysis is to evaluate rates of discontinuation and nonpublication of Randomized controlled trials (RCTs) of therapeutic interventions to treat chronic pain.

Using ClinicalTrials.gov, a sample was obtained 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.

In our final analysis of the 408 RCTs, we found that 281 (68.9%) were published in a peer-reviewed journal and 127 (31.1%) were unpublished trials.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 In addition, 221 of 296 completed trials (74.7%) were published, and 75 (25.3%) remained unpublished after trial completion. The most common listed reason for trial discontinuation was administrative recommendations (41 of 71 trials [57.7%]), while not receiving an email reply to our standardized email from the corresponding trialist was the most common result for trial nonpublication (49 of 88 trials [55.7%]). Clinical trials funded by nonindustry sponsors were more likely to reach publication than industry-funded clinical trials (unadjusted odds ratio 1.86 [95% CI, 1.18-2.95]; adjusted odds ratio 3.01 [95% CI, 1.76-5.14]).

The rate of discontinuation of RCTs involving patients with chronic pain is concerning. Chronic pain affects many patients; thus, the importance of having quality data from clinical trials cannot be overstated. Our study indicates that chronic pain RCTs are frequently discontinued and their findings often go unpublished - all of which could provide crucial information to providers and patients regarding the treatment of chronic pain. We offer suggestions to enhance chronic pain RCT completion, thereby reducing the waste of resources in chronic pain research.