Rachel A. Kitt

Research design considerations for chronic pain prevention clinical trials: IMMPACT recommendations

Abstract Although certain risk factors can identify individuals who are most likely to develop chronic pain, few interventions to prevent chronic pain have been identified. To facilitate the identification of preventive interventions, an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain. We present general design considerations for prevention trials in populations that are at relatively high risk for developing chronic pain. Specific design considerations included subject identification, timing and duration of treatment, outcomes, timing of assessment, and adjusting for risk factors in the analyses. We provide a detailed examination of 4 models of chronic pain prevention (ie, chronic postsurgical pain, postherpetic neuralgia, chronic low back pain, and painful chemotherapy-induced peripheral neuropathy). The issues discussed can, in many instances, be extrapolated to other chronic pain conditions. These examples were selected because they are representative models of primary and secondary prevention, reflect persistent pain resulting from multiple insults (ie, surgery, viral infection, injury, and toxic or noxious element exposure), and are chronically painful conditions that are treated with a range of interventions. Improvements in the design of chronic pain prevention trials could improve assay sensitivity and thus accelerate the identification of efficacious interventions. Such interventions would have the potential to reduce the prevalence of chronic pain in the population. Additionally, standardization of outcomes in prevention clinical trials will facilitate meta-analyses and systematic reviews and improve detection of preventive strategies emerging from clinical trials.

A Comparison of the Assay Sensitivity of Average and Worst Pain Intensity in Pharmacologic Trials: An ACTTION Systematic Review and Meta-Analysis

Identifying methods to improve assay sensitivity in randomized clinical trials (RCTs) may facilitate the discovery of efficacious pain treatments. RCTs evaluating pain treatments typically use average pain intensity (API) or worst pain intensity (WPI) as the primary efficacy outcome. However, little evidence is available comparing the assay sensitivity of these 2 measures. In this systematic review and meta-analysis, we comprehensively reviewed all low back pain, osteoarthritis pain, fibromyalgia, diabetic peripheral neuropathy pain, and postherpetic neuralgia RCTs that used a parallel group design. Eligibility required: 1) primary RCT report published between 1980 and 2016, 2) comparing 1 or more active, efficacious pharmacologic pain treatment(s) with placebo, and 3) providing data on the standardized effect size (SES) for API as well as WPI for all treatment arms. Twenty-seven active versus placebo comparisons were identified in 23 eligible articles. Using a random-effects meta-analysis, API SES and WPI SES did not differ significantly (difference = -.021, 95% confidence interval = -.047 to .004, P = .12). The findings indicate that, depending on the objectives of the study, either API or WPI could be used as a primary outcome measure in clinical trials for the chronic pain conditions included in this analysis. PERSPECTIVE Understanding the comparative assay sensitivity of API and WPI may advance pain treatment research. A meta-analysis of trials of efficacious pharmacologic treatments in 5 pain conditions did not show a statistically significant difference between the assay sensitivity of API and WPI.

Research Design Characteristics of Published Pharmacologic Randomized Clinical Trials for Irritable Bowel Syndrome and Chronic Pelvic Pain Conditions: An ACTTION Systematic Review

Chronic pain conditions occurring in the lower abdomen and pelvis are common, often challenging to manage, and can negatively affect health-related quality of life. Methodological challenges in designing randomized clinical trials (RCTs) for these conditions likely contributes to the limited number of available treatments. The goal of this systematic review of RCTs of pharmacologic treatments for irritable bowel syndrome and 3 common chronic pelvic pain conditions are to: 1) summarize the primary end points and entry criteria, and 2) evaluate the clarity of reporting of important methodological details. In total, 127 RCTs were included in the analysis. The most common inclusion criteria were a minimum pain duration (81%), fulfilling an established diagnostic criteria (61%), and reporting a minimum pain intensity (42%). Primary end points were identified for only 57% of trials. These end points, summarized in this article, were highly variable. The results of this systematic review can be used to inform future research to optimize the entry criteria and outcome measures for pain conditions occurring in the lower abdomen and pelvis, to increase transparency in reporting to allow for proper interpretation of RCT results for clinical and policy applications, and to facilitate the aggregation of data in meta-analyses. PERSPECTIVE This article summarizes entry criteria and outcome measures and the clarity of reporting of these important design features in RCTs of irritable bowel syndrome and 3 common chronic pelvic pain conditions. These results can be used to improve design of future trials of these largely unaddressed pain conditions.

Reporting of design features and analysis details in randomized clinical trials of procedural treatments for cancer pain: An ACTTION systematic review

Background and Objectives The objective of this study was to assess the reporting of randomized clinical trials investigating procedural treatments (eg, nerve blocks, targeted drug delivery) for cancer pain, with a focus on aspects that are particularly challenging in these trials. Methods This article presents results from a systematic review of reporting of randomized clinical trials of procedural interventions for cancer pain. Articles were identified by searching PubMed from 1966 to June 2014. Data related to quality of reporting are presented for early (1985–2004) and late periods (2005–2014). Results A total of 35 published trials were included. Approximately two-thirds of the articles clearly indicated the level of blinding. Only 26% reported a primary outcome measure. Less than half explicitly reported the number of patients who completed the trial, and only 1 reported a method that was used to accommodate missing data. Almost one-third of articles included a responder analysis, all of which specified the definition of a responder. Conclusions The goal of highlighting these deficiencies in reporting is to promote transparent reporting of details affecting the completion and interpretation of procedural cancer pain trials so that their quality can be more easily evaluated.

Reporting of data monitoring boards in publications of randomized clinical trials is often deficient: ACTTION systematic review

OBJECTIVE To examine whether primary reports of randomized clinical trials (RCTs) in six high-impact, general medical journals reported (1) whether or not a Data Monitoring Committee/Data and Safety Monitoring Board (DMC/DSMB) was used and (2) the composition of the responsibilities of the reported DSMB/DMCs. STUDY DESIGN AND SETTING Systematic review of RCTs published in 2014 in Annals of Internal Medicine, BMJ, NEJM, JAMA, JAMA Internal Medicine, and Lancet. RESULTS Of the 294 articles identified, 174 (59%) mentioned using a DMC/DSMB. Of these 174, 126 (72%) indicated at least one responsibility of the DMC/DSMB, 26% listed the names of the DMC/DSMB members, and another 14% listed both their names and affiliations. Only one article stated that a DSMB was not used. The remaining 119 articles did not report whether or not a DMC/DSMB was used, although 59 had previously stated in a clinical trials registry entry or a published protocol that a DMC/DSMB was to be used. CONCLUSIONS Considering the major role that DMC/DSMBs play in protecting participant safety, data quality, and interim analyses in RCTs, we recommend that authors of publications of RCTs report whether a DMC/DSMB was used and the responsibilities and members of DMC/DSMBs to increase transparency regarding study conduct.

Interpretation of CIs in clinical trials with non-significant results: systematic review and recommendations

Objectives Interpretation of CIs in randomised clinical trials (RCTs) with treatment effects that are not statistically significant can distinguish between results that are ‘negative’ (the data are not consistent with a clinically meaningful treatment effect) or ‘inconclusive’ (the data remain consistent with the possibility of a clinically meaningful treatment effect). This interpretation is important to ensure that potentially beneficial treatments are not prematurely abandoned in future research or clinical practice based on invalid conclusions. Design Systematic review of RCT reports published in 2014 in Annals of Internal Medicine, New England Journal of Medicine, JAMA, JAMA Internal Medicine and The Lancet (n=247). Results 85 of 99 articles with statistically non-significant results reported CIs for the treatment effect. Only 17 of those 99 articles interpreted the CI. Of the 22 articles in which CIs indicated an inconclusive result, only four acknowledged that the study could not rule out a clinically meaningful treatment effect. Conclusions Interpretation of CIs is important but occurs infrequently in study reports of trials with treatment effects that are not statistically significant. Increased author interpretation of CIs could improve application of RCT results. Reporting recommendations are provided.